MiceDNA Viral Infections

Non-envelopedAdenovirus DDX:

Mouse Adenovirus-1 Murine adenovirus A Polyomavirus, cytomegalovirus

Mouse Adenovirus-2 Murine adenovirus B Enterotropic runting Intestinal epithelial are unique to Madv-2

EnvelopedHerpesvirusBetaherpes

Mouse Cytomegalovirus Murid Herpesviris -1 salivary glands

Mouse Thymic Virus (MTLV) Murid Herpesvirus -3 INIB Thymus Thymic necrosis, granuloma DDX: Coronavirus or stressPolyomaviridae

Murine Polyomavirus INIB Multifocal necrosis and inflammation

K-Virus liver, lung, brain, spleen

Parvoviridae

Mice Minute Virus (MVM) Kidney, intestine, lymphoid tissue, liver

Mouse Parvovirus 1

Poxviridae

Ectromelia Ectromelia virus (ECTV)

MousePox

RNA Virus

Arenavirus zoonotic

Arterivirus

Coronavirus Murine Hepatitis Virus (MHV)

Paramyxoviridae

Replicate in nucelus; INIB

Macrophage, endothelial cells, adrenal cortex, renal tubule, thymus

Hemorrhagic encephalitis in susceptible mice; Hemorrhagic enteritis, fatty liver,

wasting disease

thymic involution, necrosis of liver and spleen

Replicate in nucleus and

cause cytomegalic

inclusions with INIB and ICIB

Does not cross the placenta, may cause fetal death and resorption, delayed birth,

runts

Eosinophilic INIB, ICIB, in salivary

glands, ;lymphoplasmacytic infiltration of the interstitium,

focal necrosis

DDX for sialoadenitis w/ Inclusions: Polyomavirus, (no inclusions=Reovirus 3, Mouse thymic virus, Mammary

tumor virus)

Salivary gland tumors, kidneys, 40 other cell types

Tumors of mammary gland, salivary gland, thymus, skin

tumors, renal sarcoma, osteosarcoma,

hemangiosarcoma, fibrosarcoma

DDX: Mouse hepatitis, Pneumocystis, Sendai, Pneumonia virus of mice, adneovirus, cytomegalovirus

Murine pneumotropic virus (MPtV

INIB in vascular endothelium

replicates in intestinal capillary endothelium

pulmonary vascular edema and hemorrhage

DDX: Polyoma virus of mouse, adenovirus, cytomegalovirus

INIB in spleen mononuclear

cells

hemorrhage, hematopoietic involution, renal papillary infarction

more pathogenic for hemopoietic tissue than MPV; Targets outer granular layer of

cerebellum

similar to MVM, but infects mice of all ages

related- vaccinia, variola, monkeypox, cowpox

INIB, basophilic to eosinophilic

especially hepatocytes

Direct contact through cutaneous trauma; readily infects placenta and

fetus

spleen, liver, kidney, lung, intestine; amputating lesions, intestinal

hemorrhage, necrosis

necrosis of spleen, liver, lymph node, peyer's patches,

thymus

DDX: Hepatitis, MHV, Tyzzers, Salmonella, bite wounds, alopecia, hypersensitivity, gangrene

Lymphocytic Choriomeningitis Virus

runts, wasting, vasculitis,

glomerulonephritis, lymphocytic infiltration in brain , liver,

adrenal, kidney, lung

necrotizing hepatitis, lymphocytic meningitis

DDX: Lymphoproliferative disorders, amyloidosis, glomerulonephritis, Chronic renal disease

Lactate Dehydrogenase-Elevating Virus Infection

(LDV)

Necrosis of T cell in lymhpoid

tissue, generalized

splenomegaly, lymphadenomeg

aly

Scattered neuronolysis with apoptosis and perivasculitis, non-suppurative leptomeningitis, myelitis, radiculitis

DDX: Mouse encephalomyelitis virus (MEV), MHV, or retrovirus

hepatic nodular hyperplasia with

parenchymal collapse and

fibrosis, splenic necrosis,

Neurologic, vestibular, paresis in

immunodeficient mice

necrosis and syncytia of parenchyma and endothelial cells- liver spleen, red

and white pulp, GALT, thymys and bone marrow

enterotropic MHV- depends on age- neonates have villous attenuation,

syncytia, and mucosal necrosis

Residual brain lesions- perivascular cuffing of

lymphocytes and vacuolation/ granulomatous serositis in IFN

deficient mice

DDX: adults- Salmonella, Tyzzers, Mousepox; Neonates- Reovirus, Cytomegalovirus, adenovirus; Enteritis- epizootic

diarrhea, salmonella, Tyzzers, Reovirus; Demyelinating- Mouse encephalomyelitis virus, LDV, Polyoma virus in

immunodeficient mice

Murine pneumovirus (MPV)

Sendai Virus Sendai Virus (SeV)

Picornaviridae

Reoviridae

mouse reovirus neonatal disease

Rotavirus-A (RV-A)

Caliciviridae

Norovirus Murine norovirus (MNV-1)

Retroviridae

general info

MMTV- tropism for mammary tissue

MuSV-sarcomavirus

MuLV Exogenous and endogenous

MMTV

Bacterial Infections

Enteric Infections

Pneumonia virus of mice (PVM)

Mild necrotizing rhinitis,

necrotizing bronchiolitis,

non-suppurative interstitial

pneumonia with neutrophils,

lymphocytes and macrophages

Alveolar septae are thickened with edema and macrophages and

leukocytes, and alveolar spaces are collapsed and filled with fibrin, blood and

macrophages and large polygonal mononuclear cells (detached Type II

pneumocytes)

DDX: Pulmonary disease and wasting- Sendai and Pneumocystis murinus (immunodeficient) PVM tends not

to induce bronchiolar hypertrophy like Sendai virus

Infects respiratory

epithelium and Type II

pneumocytes

CD-8 Triggered apoptosis of infected cells

Segmental necrotizing airways with inflammation as well as foci of interstitial

pneumonia

neutrophils, macrophages, lymphocytes, fibrin in alveoli,

atelectasis; Bronchiolar epithelium may be

hyppertrophic and hyperplastic prior to apoptosis

DDX: Mycoplasma, Corynebacterium kutscheri. Mild lesions can look like PVM or MHV. Immunodeficient mice

can look like PVM or Pneumocystis murina

Mouse encephalomyelitis virusMEV or Theilovirus (ThV);

Mouse poliovirus or Theiler's virus

Viral encephalitis and

demyelination

attacks neurons and glia; neuronolysis, neuronophagia, microgliosis, non-

suppurative meningitis and perivasculitis

SCID mice have marked vacuolation and enlargement of affected neurons, in the brain stem and ventral horn of a spinal

cord.

DDX: neurological disease- trauma, neoplasia, otitis, MHV, LDV; In immunodeficient mice polyoma virus

Mammalian orhtoreovirus (MRV)

enters through Peyer's patches

Runted, jaundiced, steatorrhea, dorsal alopecia

Diffuse encephalitis with vascular distribution;

Necrotizing myocarditis, necrosis of lymphoid tissue, necrotizing hepatitis, portal

hepatitis, acinar pancreatitis, and sialodacryoadenitis

DDX: Neonatal disease with steatorrhea- mouse hepatitis virus, EDIM virus, Salmonella

Epizootic Diarrhea of Infant Mice (EDIM)

Infects terminally differentiated enterocytes of

villi of small and large intestine

Loose mustard colored feces staining the perineum

Hydropic change and vacuolation of enterocytes at the tips of villi

DDX: Enterotropic MHV, MAdV, reovirus, Salmonellosis, Tyzzer's disease

Non-pathogenic, tropism for

macrophages and dendritic

cells, replicate in lung liver, and

lymphoid organs in macrophages

Alveolitis, pulmonary edema, coagulation necrosis in liver, minimal inflammation, necrotizing splenitis,

endothelial hypertrophy in STAT1 null mice

Multiofcal mononuclear hepatitis, interstitial pneumonia, pleuritis,

peritonitis

retroelements make up 37% of the mouse genome, most considered genetic parasites. These require transcription

from RNA to DNA- gag, pro, pol, env genes flanked by LTR's

MuLV and MMTV's encode their own reverse transcriptase and are incorporated into the genome

(provirus)

Most are methylated and transcriptionally silent due to mutation

Other autonomous retroelement flanked by LTR's are: Intracisternal A particles

(IAP's), MusD elements, VL30 elements, glutathione tRNA primer binding sites

(GLN's), and murine endogenous retroelements (MuERV's- include

MuERVC, MuRRS, MuRVY's) These are mi

LINE's are long interspersed nucleotide sequences and

make up 20% of the genome- these lack LTR's

Non-autonomous retroelements must borrow reverse transriptase- they encode no proteins but are flanked by

LTR's (early transposons (Etns), Short interspersed nuclear elements (SINES); Also there are numerous LTR's

with no internal reading frame

Exogenous retroviruses are transmitted horizontally as conventional viruses

Endogenous retroelements are mostly defective, they do represent mobile DNA that can re-integrate in other

regions of the genome during cell division withour virion assembly and re-infectionLTR's encode superantigen

gene (sag)

LTR's include enhancers, promotors, which dictate transcriptional acitivty and tissue

specificity

incorporate a host cell proto-oncogene that directly alters

cell division

Once in the viral genome they are

called viral oncogenes and may be mutated to increase their pathogenicity,

but also may be defective

Acute transforming retroviruses have such v-onc genes and are capable of transforming a cell quickly instead of

relying on random insertional mutagenesis

transmitted through milk,

semen, saliva, etc

Re-integration into the somatic genome results in random insertional

mutagenesis and neoplasia follows integration near host proto-oncogenes

Mouse lymphoma - B cell and arise in spleen.

Mammary gland neoplasia, lymphocytotropic

insertional mutagenesis transforms

lymphocytes

can be endogenous or exogenous and transmitted in milk

Citrobacter rodentium

Escherichia coli Coliform typhlocolitis perineal fecal staining DDX: C rodentium, Helicobacter, Enterotropic MHV

Clostridium piliforme Tyzzer's Disease

Helicobacter hepaticus DDX: Salmonella, Proteus, Tyzzers, MHV, ectromelia

Salmonella Typhimuriumintracellular, in macrophages histiocytic granuloma

Enteritidis

Chlamydiae obligate intracellular

Klebsiella

Leptospira

interrogans ser copenhageni interstitial nephritis and tubular damage

Mycoplasma M pulmonis Mitogenic for B cells

M neurolyitcum Rolling disease exotoxin conjunctivitis

Transmissible murine colonic hyperplasia (TMCH)

hyperplastic, catarrhal colitis;

Induce dissolution of brush border, actin filament

rearrangement, pedestal

formation similar to attaching and effacing E coli

(EPEC and EHEC)

non-flagellated, species specific, requires direct contact, colonizes cecum

and colon, attachment mediated by bacterial intimin and Type III proteins including translocated intimin receptor

(Tir)

bacterial colonization elicits intense mucosal epithelial hyperplasia/ cryptal

cysts that fill with mucin; rectal prolapse; contracted thickended colon, erosion,

multifocal hepatitis and splenitis

Acquired immune response is necessary for clearance but is also a major factor in disease

severity

DDX: hyperplastic colitis, E coli, Helicobacter, enterotropic MHV

Large intestinal hyperplastic

lesions, thickended colon

mucosa, mucosal

hyperplasia

red mucosa, inflammation,

necrosis in mucosa and muscularis

multifocal liver necrosis with neutrophils, myocyte degneration, myocarditis,

intracellular bacteria

DDX: MHV, mousepox, salmonellosis, pseudomoniasis, corynebacterium, Helicobacter spp, clostridial enteropathy

Hyperplastic typhlocolitis and hepatitis

4mm white foci in liver, hypertrophy and hyperplasia of ito cells and

oval cells

bile duct hyperplasia, fibrosis, helical microorganisms

mucosal crypt hyperplasia, organisms in crypt lumen

Hepatocellular tumors, typhlocolitis (IBD)

fibriae to M cells-->

phagocytosis by enterocytes-->

diarrhea, conjunctivitis, splenomegaly, pale liver foci, fibrinous peritonitis,

venous thrombosis,

DDX: Tyzzer's, coronaviral hepatitis, mousepox, Helicobacter, pseudomoniasis

pulmonary perivascular and peribronchiolar

lymphocyte infiltration and

non-suppurative interstitial

pneumonia

organisms grow within bronchiolar epithelium, type 1 alveolar cells,

macrophages,, intracytoplasmic vesicles containing inclusions

Cilia-Associated Respiratory Bacillus

Chronic suppurative cranioventral

bronchopneumonia with marked peribronchiolar infiltration with

lymphocytes and plasma cells

Warthin starry shows long filamentous bacteria along cilia

associated with viruses like Sendai and PVM

K oxytoca- suppurative female repro tract lesions

old mice with suppurative endometritis,

cystic endometrial hyperplasia, salpingitis,

perioophoritis/ peritonitis

(abscesses and adhesions)

interrogans ser icterohemorrhagiae

pulmonary fibrinoid vasculitis, thrombosis, hemorrhage

renal tubular necrosis and

interstitial nephritis

Lethal disease, discohesion of hepatic cords, hyperplasia

of Kupffer cells and macrophages,

focal hepatic necrosis,

respiratory and genital tract disease ans sometimes

arthritis

colonizes the apical cell

membranes or respiratory epithelium,

exacerbated by viral infections

and Pasteurella

mucopurulent exudate, vestibular signs, bronchiolectasiss, abscessation,

suppurative rhinitis, hyperplasia of mucosal glands

flat epithelium, syncytia, peribronchiolar and

perivascular lymphocytes, metaplasia of respiratory

epithelium

DDX: CAR bacillus, Sendai, Streptobacillus and Corynebacterium (Pneumonia and arthritis)

M Coccoides severe anemia and death

M hemomuris typically infects rats

Lawsonia intracellularis

Pasteurella pneumotropica

Proteus mirabilis Suppurative pyelonephritis Fibrinous peritonitis septic thrombi in vessels

Pseudomonas aeruginosa DDX: Corynebacterium kutscheri, Enterobacter cloacae

Burkholderia gladioli

Coxiella burnetti

Streptobacillus monoliformis Rat Bite Fever- potentially fatal zoonotic

Clostridium perfringens necrotizing and hyperplastic changes

Clostridium difficile C diff toxin A and B

Corynebacterium kutscheri hematogenous DDX: Staph, Strep, Mycoplasma (arthritis)

Corynebacterium bovis Hyperkeratosis DDX: Low humidity, some other bacterial dermaitis

Corynebacterium spp Conjunctivitis

Staphylococci Staphylococci Conjunctivitis

Necrotizing dermatitis

Lymphadenitis

Streptococci Streptococcus Lancefield groups A, B, C, G

Strep agalactiae Group B

Strep equisimilis Group C

transmitted by Polyplax serrata- louse

attahced to erythrocytes and

free in plamsa

Proloferative enteritis, typhlitis or colitis

rats hamsters, guinea pigs and

rabits

Respiratory, enteric and genital tracts

Conjunctivitis, panophthalmitis, dacryoadenitis,

periorbital abscressation, rhinitis, otitis,

cervical lymphadenitis

Necrotizing dermatitis, mastitis, metritis, UTI, abortions

ddx: fighting injuries, M pulmonis, pneumocystis, Sendai virus

splenomegaly, multifocal hepatic lesions in SCID

mice

Conjunctivitis, nasal discharge

subcutaenous edema and

sudden death

ulcerative lymphangitis, vasculitis, thrombosis, necrosis, hemorrhage

Mice that received bovine xenografts

necrotizing hepatitis, with

Kupffer cell and Ito cell

hyperplasia, and basophilic

cytoplasmic inclusions

Commensal of respiratory tract

Cervical lymphadenitis

Suppurative embolic nephritis, polyarthritis, osteomyelitis

DDX: pseudomoniasis, corynebacterial, staphylococcal, streptococcal infections, (mycoplasma and

corynebacterium for arthritis)

Non-Type A, type B and Type D

large or small intestine

generalized lymphoid apoptosis and renal tubular vacuolation

DDX: Tyzzer's disease, (and hyperplasia- citrobacter, Helicobacter, E coli)

Pneumonia, caseous necrosis

liver, kidney, lungs, lymph

nodes

conjunctivitis, thrombosis, gram positive bacilli

lipophilic and grows in keratin

Marked epidermal hyperplasia, orthokeratotic hyperkeratosis ans mononuclear and PMN cells in the

dermis

DDX: Ectromelia virus, Pasteurella pneumotropica, Staphylococcus, Foreign bodies, genetic factors (entropion

etc

hemolysins, nucleases, proteases,

lipases, hyaluronidase,

collagenase

exfoliative exotoxins, leukocidin, Enterotoxins and Toxic shock syndrome

toxin-1

superficial colonization with underlying burn like lesions

B6 mice prone to trichotillomania causing

ulcerative dermatitis followed by colonization with staph and

then necrotizing dermatitis

DDX: other bacterial abscesses, Streptococcal necrotizing dermatitis, amputation of the tail (mousepox)

Gram pos bacteria

surrounded by splendore

hoeppli material (botryomycosis)

Chronic disease can cause multisystemic amyloidosis and

splenomegaly

Group A- bacteremia,

cervical lymphadenitis

Group B- Meningoencephalitis, ependymitits, periventriculitis, (from nose), pyelonephritis, septicemia

DBA/2 mice with pyelonephritis

and subsequent bacteriemia with

disseminated lesions to the

heart, kidneys, spleen, liver, uterus, thorax

subcutaneous, hepatic, and abdominal abscesses

Group G

Enterotoccus Lancefield group D enterococcus durans and faecalis

Mycobacteria

M. avium intracellulare

Mycotic Infections

Dermatophytosis

Trichophyton mentagrophytes

Microsporum canis

Systemic and Pulmonary Cryptococcus neoformans B6.129S6-Cybb mice Chronic granulomatous disease

Candida tropicalis B6-p47 Null mice Trichosporon beigelii

ActinomycesGastric

Candida pintolopesii

Canida albicans normal inhabitant

Pneumocytsis murina

Parasitic diseaseEctoparasites

Acariasis fur mites

Myobia musculi hypersensitivity

Follicle Mites Demodex musculiPsorergates rare

Ornithonyssus bacoti tropical rat mite blood sucking intense pruritis

Pediculosis Louse

Polyplax serrata

Eimeria

Cryptosporidium muris

Cryptosporidium parvum

Giardia muris lumen of duodenum

Spironucleus muris (formerly hexamita)

Toxoplasma gondii rare in lab mice

Sarcocystis muris rare in lab mice

Klossiella muris renal coccidiosis

Necrotizing dermatitis with vasculitis and

thrombosis

with Pseudomonas

can cause bacteremia in

SCID mice

asymptomatic with subpleural granulomas

DDX: M pulmonis, Corynebacterium kutscheri, Freunds adjuvant lesions

Cuplike crusts on head ears, face, tail, extremities

epithelial debris, exudate,

mycelia, masses of arthrospores, with underlying

dermatitis

Defective NADPH oxidase

Paecilomyces, Aspergillus, Rhizopus, Candida

Defective NADPH oxidase

yeast of the surface mucosa of the glandular stomach

Pseudomemrane formation with

epithelial hyperplasia and hyperkeratosis and leukocytes

Pseudohyphae in the

kersatinized layer

Non-filamentous yeast-like trophic forms

adhere to type 1 pneumocytes

Asci (cysts) are also present and

contain 8 ascospores

carriers are asymptomatic and disease presents in immunosuppressed mice

causing pneumonia

Interstitial pneumonia with proteinaceous exudate in the alveolar lumina,

thickening of alveolar septa

3-5 um cysts, irregularly flattened

DDX: viral pneumonia, Sendai virus, PVM, Congestive heart failure

Myobia, Radfordia, Mycoptes, Tichoecius

epidermal hyperplasia and hyperkeratosis

DDX: Pediculosis, trauma, bacterial dermatitis, dermatophytosis, hair chewing, muzzle alopecia

(mechanical)

do not feed on blood but secretions; cause pruritis and self trauma leading to

hair loss and secondary infections

heavy infestations can result in anemia

Protozoal endoparasites

vermiformis, falciformis, papillata, ferrisi

gastric mucosa, relatively non-pathogenic

small intestine, marginally pathogenic

enteritis secondary to

viral infections

cholangiohepatitis with focal hepatic necrosis, peribiliary fibrosis

poor hair coat, distention

commensal inghabitant of

intestine

crypts and intervillous spaces are distended, lymphocytes and plasma

cells

cats definitive hosts

cats definitive hosts

Encephalitozoon cuniculi

Helminths

Oxyuriasis (pinworms)

Tapeworms Rodentolepis nana all use arthropods as intermediate hosts

Hymenolepis diminuta

Rodentolepis microstoma

adults live in cats

Amyloidosis 2 types AA inflammatory response spleen liver intestine and kidney

AapoAII produced by liver

nasal mucosa

Soft Tissue Calcification

BALB/c

C3H

DBA mice

DBA, C3H, BALB

AMP B6, 129

Hyalinosis part of the syndrome

Reye's like Syndrome

Male aggression DBA, Swiss, BALB/c

Stereotypy repetitive funtionless behavior

Barbering tritrichotillomania females> males B6 and A2G self or conspecific can initiate ulcerative dermatitisPenis self mutilation B6

microsporidiosis (more like fungi)

granulomatous hepatitis, interstitial nephritis,

meningoencephalitis

spores are gram positive

rectal prolapse, intussusception, fecal impaction, diarrhea

nana also capable of superinfections via direct ife cycles

cysticerci in lamina propria and threadlike adults adults in

lumen

larger and intermediate forms do not appear in the mucosa

as large as diminuta and often exist in bile ducts or pancreatic ducts inciting

pancreatitis and cholangitis

Taenia taeniaformis (cysticercus fasciolaris)

mice ar intermediate host

larval form in stobilocercus (cysticercus fasciolaris)

scolex and segments within a cyst found in the liver (may resemble adult tapeworm)

Nutritional and Metabolic

serum precursor apoSAA

precursors are degraded by macrophages to AA fibrils

DDX: glomerular hyalinosis (agre related), glomerulonephritis, hydronephrosis, spontaneous cardiac

atrial thrombosis

Primary or Senile Amyloid

Adrenals, intestine, heart, lungs, thyroid, parathyroid, ovaries, testes

some say it is not amyloid since it does not stain with Congo red and is trichrome

positive

Epicardial mineralization with fibrosis of the RV free wall

foci of degeneration and mineralization throughout LV

myocardium and IVS

Skeletal myofiber mineralization

epicardial and myocardial mineralization

dystophic mineralization in the aorta, testes, tongue, muscle, cornea, kidney, stomach, small intestine, ovary

in the tongue can form inflammatory polyps

Dystrophic mineralization of the superficial corneal stroma

Acidophilic Macrophage Pneumonia/ Epithelial

hyalinosis

focal to diffuse accumulation of acidophilic crystals within

macrophages, alveolar spaces, and airways

cytoplasm packed with needle to rhomboid shaped crystals

Any disease that impairs normal pulmonary clearance can predispose to

AMP

olfactory, nasal respiratory, middle ear,

trachea, lung, stomach, gall

bladder, bile duct and pancreatic duct epithelium

In the cytoplasm of epithelial cells, with blebbing and filling of glands

hepatoencephalopathy and fatty degeneration of the

viscera

anticedent viral infections and aspirin therapy are

participating factors in humans

mitochondrial swelling with hepatocyte

dysfunction in the primary

lesion

livers are swollen greasy and pale, kidneys are swollen

hepatic lipidosis, Alzheimers type II astrocytes, intestinal lesions associated

with MHV are variable

DDX: BALB/c hepatic fatty degeneration (lesser degree of change)

Behavioral Disorders

The presence of males will synchronize estrus (Witten

effect)

diffuse wounds or centered

around the tail and external

genitalia

Bar-mouthing, jumping, circling, somersaulting,

routetracing

HusbandryMechanical muzzle alopecia

Ringtail low humidity

Cotton Sloughing

Spinal fracture cage lid closure

Dehydration check for hydrocephalus

Hypo-Hyperthermia

Frostbite gangrene nude mice proneEar gangrene and Notching Albino Swiss and C3H

Alopecia areata C3H mice

Alopecia of B6 mice behavioral disorder Myobia hypersensitivity

Clown Mouse syndrome weaning age mice runted and general alopecia associated with MHV

Siezures DBA/2, SJL, LP audiogenic siezures

Hypocallosity aplasia of corpus callosum

Hydrocephalus C57Bl

Vacuolation of White Matter fixation artifact

thalamus of old mice

Cochlear degeneration

Spontaneous corneal opacity

Blepharitis and Conjunctivitis suppurative conjunctivitis

C57BL females>males assymetric

Retinal degeneration Homozygous rd-1 allele

Malocclusion B6 hereditaryForeign Body periodonittis

Celft lip palate

Megaesophagus

Gastric mucosal hyperplasia etiology unknownIleus in lactating mice abdominal distention

Liver Problems- incidentalCytomegaly of hepatocytes

Fatty change BALB- normal

age related

Bile duct proliferation

Polyarteritis small to medium sized arteries usually incidental

Vestibular syndrome manifestation of polyarteritis Head tilt, circling

annular constrictions of the tail and feet

necrosis and sloughing of digits due to cotton fibers

require large volumes of drinking water

Massive thymic apoptosis

mice are inefficiaently homeothermic

Massive thymic apoptosis

Aging Degenerative and Miscellaneous

irregular diffuse alopecia of the dorsal and ventral trunk

hairloss increases with

age

dense anagen follicles with dystrophic hair follicles, melanin incontinence, interfollicular epidermal thickening,

perifollicular mononuclear leukocyte infiltrates

predispose to necrotizing dermatitis

hyperkeratosis and glabrous

skin

neuronal necrosis of

cortex, hippocampus,

thalamus, generalized

gliosis

centrilobular coagulation necrosis of liverejaculation with retention of urethral

plugs resulting on obstructive uropathy

domes, runted and dehydrated

reduced neuronal

proliferation, defects in

ependyma, lamination of

cortex, microencephaly

Multilaminated mineralized concretions

acute to chronic inflammatory changes

vascularization, mineralization of corneal basement

membranes

abscessation of meibomian glands

corynebacterium, staph,

pasteurella pneumotropica

Microphthalmia and Anophthalmia

absence or degeneration of rods, outer nuclear layer,

outer plexiform layer,

smooth muscle I nthe abdominal segment

aplasia of the myenteric plexus with fibrosis

Eosinophilic cytoplasmic inclusions

intranucelar cytoplasmic invaginations

polyploidy, karyomegaly, anisokaryoiss, polykarya

Biliary epithelial hyalinosis and crystals

fibrinoid degeneration and necrosis of tunica media

neutrophilic or mononuclear

left side usually

Pulmonary histiocytosis lipid laden macrophages

Alveolar lipoproteinosis

Alveolar hemorrhage

Aspiration pneumonia

Murine Urologic Syndrome obstructive uropathy

Amyloidosis

LCMV and retroviruses

Hydronephrosis usually incidentsl

renal InfarctionPolycystic disesae BALB/c

Renal tubular hyaline bodies

Inclusion body nephritis

Chloroform Toxicity Renal tubular necrosis mineralization DBA and C3H mice

NSAID nephropathy

Mucometra/hydrometra BALB/c, B6, DBA abdominal distension

Cystic endometrial hyperplasia aged female mice

Adenomyosis oftne extends to serosa DDX- neoplasia

Mammary Hyperplasia virgin female FVB/N

Bulbourethral glands cysts Small pear shaped

sternebrae, vertebrae, femurs aged female B6C3F1 DDX- histiocytic sarcoma, osteosarcoma

NeoplasmsMammary Tumors C3H/HeTesticular Tumorsa 129/Sv

Multicentric lymphoma BALB/c

Atrial thrombosis and heart failure

thrombosis of the auricle leading to heart failure

precipitated by multisystemic amyloidosis

Perivascular lymphoid infiltrates

mild to severe in the adventitia of pulmonary vessels

antecedent to lymphoproliferative disorders

cholesterol or hemoglobin crystals

progressive intraalveolar accumulation of granular pale

eosinophilic phospholipid (surfactant)

hypertrophy and vacuolation of Type II pneumocytes

may overlap with acidophilic

macrophage pneumonia

extravasation of blood into alveolar spaces is common

agonal finding

Freunds adjuvant pulmonary granulomata

cellulitis, paraphimosis, hydronephrosis

prostatitis, cystitis, urethritis, balanoposthitis

DDX- agonal release of coagulum from accessory sex glands

Chronic Glomerulonephritis/ Glomerulopathy

Membranoproliferative glomerulonephritis

chronic progressive nephropathy (resembles the

disease in Rats)

non-specific basement membrane thickening (glomerular hyalinosis)

glomerular sclerosis, tubular degeneration, regeneration,

interstitial inflammation, dilated tubules with protein

rich fluid

DDX- renal papillary necrosis due to amyloidosis

Hyaline eosinophilic bodies in cytoplasm of tubules

association with histiocytic sarcomas

Homogenous intranuclear eosinophilic inclusions

adjacent interstitial infiltrates of lymphocytes

negative for Polyoma virus, K virus, adenovirus

Males > Females; castration eliminates sensitivity

Tubular degeneration with mineralization

may progress to chronic nephropathy

Pale kidneys with irregular outlines,

tubular degeneration and atrophy in

cortex and medulla

one or both uterine horns

dilated

some have congenital imperforate vagina

DDX- Pyometra, retained fetuses, neoplasia

may be associated with secondary bacterial

pyometras

glandular invasion of the myometrium

at the base of penis and embedded in skeletal muscle

secretions are part of

copulatory plug

Cystic glands present as unilateral or bilateral swellings of the perineum

may be suppurative- Staph aureus, Pasteurella pneumotropica

Seminal Vesicular Dilatation and atrophy

Pseudocanalization and Megalokaryocytosis of male

reproductive epithelium

Fibro-osseus lesions in Aged mice

bone marrow replaced by

fibroblast like cells and

osteoblasts embedded in an

eosinophilic matrix

can extend into the periosteum; Non malignant

Thymic lymphoma AKRHepatocellular neoplasia DBA

Lymhphoid neoplasms B cell Precursor B cell

Mature B cell small cell

multifocal in spleen

Follicular B cell

Resemble follicular lymphomas spleen, LN, mediastimum can be histiocyte associated

Plasma cell PlasmacytomaExtraosseus plasmacytomaanaplastic plasmacytoma

T cell Precursor T cell enlarged thymuses

Mature T cell Small cell

Non-Lymphoid neoplasms

With maturationWithout maturation

Erythroid leukemiasMegakaryocytic leukemia

Biphenotypic leukemiahematopoeitic sarcoma

Granulocytic

Histiocytic sarcoma

Mast cellMyeloid dysplasia

Myelodysplastic syndrome

Genetic myeloproliferationMyeloproliferative disease

Mammary tumorsGlandular composed of glands

Acinar

Cribriform

Papillary

Solid

Lymhpoid and NonLymphoid Hematopoeitic Neoplasia

multisystemic, lung , kidney, often with leukemic phase

spleninc marginal zone

arise in marginal zones and extend into both red and white pulp

spleens are enlarged; cells have abundant cytoplasm

Most common; spleen, Peyer's patches, Mesenteric lymph nodes

arise from follicles; typicallyu low grade and resemble germinal centers with

large cells

Diffuse large B cell

arise from centroblasts in the splenic white pulp, medium sized with scant cytoplasm

Burkitt-lymphoma

Burkitt-like lymphoma

Lymphoblastic . Not Herpes virus associated

B natural killer cell

Cd4-/ Cd8-, CD3+

medium sized and uniform with scant cytoplasm

Splenomegaly, lymphadenomegaly, not Thymic associated

T-natural Killer cell

Large cell anaplastic

Myeloid (granulocytic) Leukemias

originates in the spleen, can go to BM, liver, lung,

adrenal. Kidneys

sparing of splenic follicles/ splenomegalylarge vesicular nuclei, round, indented or

ring shaped

Myeloproliferative disease-like myeloid leukemia

enlarged spleen, multifocal

nodules in lungs, liver, ovaries,

uterus, kidney, bone marrow, lymph nodes

large nuclei and multinucleated giant cells

erythrophagocytosis espiecially in the liver

Cytopenia with increased blasts

Non-reactive Myeloid proliferation

glandular structures with small lumina (MMTV)

MMTV's are either exogenous or endogenous (low grade)

multicentric and multinodular, well

circumscribed, pulmonary

metastasis is common

Sheets or nests forming lumina with round punched out

spaces

fingerlike projections of epithelium covering a central

vascular core

solid sheets of epithelium with little or no glandular

differentiation

Squamous

Fibroadenoma

Adenomyoepithelioma myoepithelium and glands

Adenosquamous

NOS

Pulmonary Tumors

Primary pulmonary Adenoma DDX- focal alveoalr epithelial cell hyperplasia (older mice)

columnar cells

PapillomaSquamous cell carcinoma

Adenosquamous carcinomaneuroendocrine carcinomaHepatocellular neoplasia

Aged males > females A and DBA strains Helicobacter spp

Hepatoblastoma or forming rows and rosettes

CholangiomaCholangiocarcinoma

hemangiomahemangiosarcomaHistiocytic sarcomaIto cell tumors (rare)

Harderian gland tumors

Adenocarcinomas

Myoepitheliomas BALB/c and BALB/cBy Females > Males

Reproductive NeoplasmsFemale

Papillary cystadenomasovarian tubular adenomas

Dysgerminomas rarehemangiomas/sarcomas urterus

adenocarcinomasLeiomyosarcomas

Histiocytic sarcomasMale

Teratomas of the testisExtragonadla teratoma perigenital region

Rhabdomyosarcomas

Mesenchymal tumors

Soft tissue sarcomas Trp53Multicentric osteomas OF-1 mouse

Primary Osteosarcomas present with posterior paralysis

Endocrine Neoplasms

Pituitary Gland Adenomas B6 and Swiss mice, FVB/N prolactin producing Females > Males

Adrenocortical adenomasPheochromocytomas

Squamous cells with or without differentiation, no

glandular pattern

Myxoid and fibrous stroma and glands

glandular and squamous elements

Does not resemble any of the above

A strain is highly susceptible due to a mutated K-ras allele

enhanced with viral infections such as Sendai

originate from Type II

pneumocytes or its precursor

common to Clara cells

closely packed cuboidal to lining remnants of alveolar septa with sparse

collagenous stroma

Cells are non ciliated and may have mucinous differentiation

Primary pulmonary adenocarcinoma

Sub-pleural masses +/- invasion and seeding of visceral and parietal pleura

Hepatocellular adenomas and carcinomas

Antecedent: cell alteration, clear cell foci, basophilic foci, eosinophilic cell foci

grey to tan nodules, trabecular and solid types,

well circumscribed, unencapsulated,

anisokaryosis, karyomegaly, cytomegaly

organoid structures arranged around vascular channels

papillary cystadenomas or solid adenomas

slow growing, appear late in life

protrusion of the eye with porphyrin staining

lobulated resilient, light tan to white mass in the retroorbital

space

well differentiated epithelial cells with vacuolated cytoplasm

highly invasive with infiltration of bone and othe rstructures of

the head

Arise from submaxillary and parotid salivary

glands

may also be associated with mammary, preputial, and Harderian glands

Cystic chambers containing serous fluid (necrosis)/ large pleiomorphic spindle cells with epithelial and mesenchymal

features

metastasis to lungs, myeloid hyperplasia of bone marrow

and spleen

granulosa cell and thecal tumors

Uterine endometrial stromal tumors

Sebaceosquamous adenomas and carcinomas

pregutial glands of both males and females

Mesenchymal and Bone Neoplasms

arise from skeletal muscle in BALB/cj, and BALB/cByJ

can be induced by carcinogens and viruses

Moloney Murine Sarcoma Virus

from spinal vertebrae, sternebrae and long bones

metastasis to lung, liver, spleen, kidney

lumbosacral region

Solid, sinusoidal, cystic, compress overlying brain

Pancreatic Islet tumorsThyroid Follicular cell

Adenomas

RatsDNA Viral Infections

Non-envelopedAdenovirus DDX:

Mouse Adenovirus MAdV-2

EnvelopedHerpesvirus

Rat Cytomegalovirus

Polyomaviridae

Parvoviridae

Group 1 Kilhams rat virus (RV)

H-3X-14RV-Y

HER virusGroup 2 Toolan's H1

HT

Group 3 Rat Parvovirus (RPV)

Poxviridae

interstitial pneumonia may be cowpox virus

RNA Virus

Coronavirus

Bunyaviridae Hantavirus genus

no disease

HPS

Rat Respiratory Virus

Rats have a serologically related virus but do not have

disease

Intranuclear inclusions in enterocytes

antigenically distinct from CMV

Salivary and Lacrimal glands

cytomegaly with INIB and ICIB

Non-suppurative interstitial inflammation

Serologically distinct from polyoma and K

virus of mice

Pneumonia and sialoadenitis

INIB in ductal epithelium

euthymic rats did not develop disease

scrotal hemorrhage with peritesticular

fibrinous exudation, necrosis and infarction

due to thrombosis

Splenomegaly, liver necrosis,

encephalomalacia

INIB in hepatocytes, endothelial cells and bile duct epithelium

cerebrallar hyoplasia, hepatitis, and jaundice

in neonates

may have reproductive disorders

DDX- pseudomoniasis septicemia, Mycoplasma

pulmonis, trauma

Turkmenia rodent Poxvirus

related to cowpox, distinct from ectromelia

dermal pox and tail amputation

Sialodacryoadenitis Virus (SDAV)

also produce pulmonary disease in

young rats

excessive lacrimation with crusts

parotid and submandibular

salivary glands are swollen

coagulation necrosis of ductal structures

nonkeratinizing squamous metaplasia

of ducts

ddx: Mycoplasma, Sendai, Pneumonia virus of mice

(pneumonia), Pseudomonas (edema), stress events, ammonia

in environment

Parkers Rat Coronavirus

rhinitis, tracheitis, interstitial pneumonia

salivary and lacrimal gland lesions

Necrotixing tracheitis, flattening of

epithelium, loss of cilia

Athymic nude rats develop chronic

wasting

aerosol and contact spread

Hantaan virus (HFRS)

Humans- thrombocytopenia,

myalgia,

Humans- pulmonary capillary leakage

Perivascular lymphohistiocytic

interstitial alveolitis

some neutrophils and type II pneumocyte

hyperplasia

DDX: Sendai, and Pneumonia virus of Mice

Paramyxoviridae

Pneumonia virus of Mice

Sendai Virus Parainfluenza 1 Mice, rat, hamster DDX: PVM, RRV, Rat corona,

Picornaviridae

Rat CardiovirusesMHG neurologicRCaV

Rotavirus

Eosinophilic ICIB DDX: E coli

Reovirus

Bacteria

GRAM (-) Enteric

Campylobacter

Lawsonia Intracellularis

Clostridium piliforme Tyzzer's disease

Helicobacter gastritis

Salmonella focal liver necrosis

GRAM (-) Respiratory

uncommon Suppurative Rhinitis

use Warthin Starry stain

Haemophilus

mice, rats, hamsters, guinea pigs, gerbils

Non-suppurative vasculitis and

interstitial alveolitis with necrosis

Perivascular infiltrates, hyperplasia of BALT,

perivasculitis

DDX: Sendai, Rat Respiratory virus, Rat coronavirus

respiratory epithelial necrosis

rhinitis, neutrophils, plasma cells, lymphocytes

hyperplastic to suppurative bronchitis and bronchiolitis with

perivascular and peribronchial cuffing

additive effect of Mycoplasma infections

Infectious Diarrhea of Infant Rats (IDIR)

villus attenuation, necrosis of

enterocytes, epithelial syncytia

Rats do not have disesae, but seroconvert

Young rats with diarrhea

filamentous weak gram negative, spore

forming obligate intracellular

Necrotizing and hemorrhagic ileitis

Enterocyte necrosis, hepatocyte necrosis , myocardial necrosis with neutrophils and mononuclear cells

Dilation of SI with flaccid dialatation

Proliferative and ulcerative typhlitis, colitis, and proctitis

enteritidis and typhimurium

Thickening of gut wall, crypt epithelial hyperplasia,

inflammation, focal ulceration

septicemia, bacterial emboli with fibrin and

exudate

Spleen- focal granulomas, fibrinous exudation and focal

necrosis

DDX- Pseudomoniasis, rotaviral enteritis, cryptosporidiosis,

management issues and Tyzzers

Bordatella bronchispetica

important in guinea pigs and Rabbits

Bronchopneumonia with peribronchial

lymphoid hyperplasia

Maybe concurrent infection with Rat

coronavirus, Mycoplasma

Cilia-Associated Respiratory Bacillus

filamentous argyrophilic bacillus

similar to primary mycoplasma

infections

Chronic suppurative bronchitis and bronchiolitis

Peribronchial cuffing with lymphocytes and

plasma cells

DDX- Mycoplasma , bacterial pneumonia, complications to

Sendai, PVM, RRV, Rat Coronavirus

M pulmonis multifocal abscesses

Intestine

GRAM (+) Respiratory

Fibrinous pleuritis

Staphylococcus Ulcerative Dermatitis bacteria in crust

Botryomycosis heads

abdominal distention

Erysipelas

Klebsiella pneumonia Opportunistic

Leptospira

Lung spleen, kidneys

Rat Bite Fever

cystitis, proctatitis

Murine Respiratory Mycoplasmosis

Catarrhal and suppurative

bronchopneumonia

dark plum colored and tan

peribronchial cuffing with lymphocytes, metaplasia and hyperplasia of

respiratory epithelium

genital tract lesions and otitis media

DDX: Corynebacterium kutscheri, CAR bacillus, Pasteurella

pneumotropica metritis

Pasteurella pneumotropica

Rhinitis, sinusitis, conjunctivitis, otitis media, suppurative bronchopneumonia, chronic necrotizing mastitis, pyometra

Corynebacterium kutscheri

Multifocal suppurative /granulomatous

necrotizing pneumonia

(pseudotuberculosis)

Multifocal nephritis and hepatitis

coagulation and caseous necrosis, hematogenous,

interstitial pneumonia,

perivascular cuffing

rib cage, submandibular, neck, ears, head, with hair

loss

hyperplasia of epidermis,

Streptococcus pneumoniae

Fibrinopurulent polyserositis and

meningitis

Suppurative bronchopneumonia

DDX: Corynebacterium, Salmonella, Pseudomonas,

Pasteurellosis

Enterococcus faeciumdurans-2

Enteropathy in Infant Rats

gram postiive bacteria on villus tips of small

intestine

Fibrinopurulent polyarthritis, myocarditis, endocarditis

Mycoplasma haemomuris

formerly hemobartonella muris

transmitted by Polyplax spinulosa

Natural infections are inapparent

abscesses in cervical, inguinal, mesenteric

lymph nodes and kidney

subclinical with no lesions

Pseudomonas aeruginosa

Septicemia, pulmonary edema,

splenomegaly, visceral ecchymoses

Endocarditis, vasculitis with thrombosis

DDX: Corynebacterium kutscheri, Pasteurella pneumotropica, Salmonellosis, Mycoplasma

Streptobacillus moniliformis

Zoonotic, maculopapular rash,

fever, headache, polyarthritis

Bacterial Pyelonephritis/ Nephritis

E. coli, Klebsiella, Pseudomonas,

Corynebacterium, Streptococcus, Enterococcus,

Proteus

Brown Norway Rats

Mycotic Infections

Dermatophytosis

Parasitic Diseases

Lice Polyplax spinulosa pruritis, anemia

Holopleura pacificaFleas Xenopsylla

LeptopsyllaNosopsyllus

Mites

Demodex spp

Notoedres muris disfigurment of the ear

Cryptosporidium

Tryanosomiasis Trypanosoma lewisi

Giardia muris small intestine

Spironucleus muris

Helminths

Syphacia obvelata cecum and colon

Syphacia muris

Aspiculuris tetraptera

Other nematodes

urinary tract

Tapeworms

Rodentolepis nana

Pulmonary Lesions of Unknown Etiology

Eosinophilic Granulomatous

Pneumonia

Multifocal pale tan to grey to red foci

Eosinophils, epithelioid macrophages, and

MNGC

Aspergillus fumigatus or niger

rhinitis with epithelial hyperplasia and

squamous metaplasia

fungus found on epithelial surfaces

Trichophyton mentagrophytes

lesions on the neck back and base of tail

Hyperkeratosis, epidermal hyperplasia, folliculitis, arthrospores

in hair shafts,

Pneumocystis carinii/ wakefieldii

alveoli contain foamy pink material with

honeycomb appearance

Numerous black trophozoites and

yeastlike cysts 3-5um in the alveoli

Type II pneumocyte proliferation and interstitial fibrosis

vector for Mycoplasma haemomuris

Radfordia ensifera (myobia ratti)

diarrhea and high mortality

Hyperplastic mucosa and blunted villi with

fusion

infected by ingestioin of fleas or flea feces

giemsa stained blood films

Catarrhal enteritis with weight loss

Pinworms (nematode): Oxyuris

eggs deposited in colon and perianal

area, embryonate and become infectious

rectal prolapse, impactions, diarrhea,

intussusceptions

Trichosomoides crassicauda

found in lumen and bladder mucosa and

renal pelvis

Rodentolepis and Hymenolepis

arthropod intermediate host

R. Microstoma

Taenia taeniaformis

Males> females

Nephrocalcinosis various dietary factors

Hydronephrosis

S-D: highly heritable

Urinary Calculi

SPF SD rats M>F

Polyarteritis Aging rats M>F

Hymenolepis diminuta

Cysticercus fasciolaris is the

larval stage

eggs ingested--> migrate through

bowel--> encyst in liver of mice

(cysticercosis)

Cat eats mouse and becomes Taenia

taeniaformis

Sarcomas may develop around the

cysticerci

Aging and Degenerative

Disorders

Chronic Progressive Nephropathy/ Nephrosis

pitted and irregular with pallor

chronic glomerulopathy/

glomerulosclerosis/ interstitial fibrosis

proteinuria/casts/ PAS positive hyaline

droplets

secondary changes: Hyperparathyroidism,

mineralization

Nephrotic syndrome- hypercholesterolemia,

hypoproteinemia, BUN/CT

Brown Norway Rat- autosomal

polygenetic disorder

Gunn Rat_ autosomal dominant

may be due to urethral obstruction by sperma

DDX: pyrelonephritis, polycystic kidneys,

renal papillary necrosis

don’t confuse with agonal copulatory

plugs

Hematuria/ renal Papillary Hyperplasia

associated with hydronephrosis

renal papilla have focal proliferation with

necrosis and hemorrhage

Myocardial Degeneration and

Necrosis

ventricular hypertrophy and pale streaks

vacuolation of the cytoplasm.

Fragmentation of sarcoplasm, loss of

cross striations, mono-nuclear cell

inflammation

interstitial fibrosis with proliferation of fibrous

tissue

Mesenteric vessels, tortuous and thickened

microscopic lesions not in lung

fibrinoid degeneration and thickening of the

media of affected arteries with smudging

of the normal architecture

mononuclear cells with few neutrophils,

thrombosis

Alveolar histiocytosis/ Alveolar proteinosis

dull pale yellow foci, subpleural

Intra-alveolar macrophages with

needle shaped crystals and

vacuolated or homogenous

eosinophilic material

Degenerative nervous system changes

Wallerian degeneration in focal

areas of the spinal cord

Segmental demyelination of the peripheral nervous

sytem

Spontaneous radiculoneuropathy-

spinal root degeneration with

muslce atrophy of the lumbar region and hind

limbs

Liver changes

Malocclusion spontaneous/genetic

Ringtail

Dehydration

Retinal Degeneration

Corneal lesions

Bedding

Chloral Hydrate Ileus

Auricular Chondritis SD/ Wistar Rats

Neopalsia

anemia and icterus

Lymphoma/ Leukemia

Polyploidy, megalokarya,

binuclear hepatocytes, intranuclear cytoplasmic

invaginations

Focal sinusoidal dilatation and peliosis, either spontaneous or

drug induced

Bile ductular proliferation, lined by atrophic epithelium,

surrounded by collagenous tissue

Miscellaneous Disorders

secondry to poor alignment of upper and lower incisor

teeth

cellultis and salivation are sequela

Annular constrictions of the skin of the tail

leading to dry gangrene

attributed to low environmental

humidity

genetic factors, low environmental temps, degree of hydration, and nutrition may be

involved

Epidermal hyperplasia with

orthokeratotic and parakeratotis

hyperkeratosis

Dilated and thrombosed vessels, necross,

hemorrhage

accompanied by porphyrin staining

around the eyes (sign of stress)

albino rats are predisposed due to unpigmented uveal

tracts

progressive reduction of photoreceptor

nuclei in the outer nuclear layer of the

central retina

Advanced disease has marked depletion and alteration of the retinal

layers with cataract formation

this muct be distinguished from peripheral retinal

degeneration (inherited disorder)

Conjunctivitis- Pasteurella,

environmental factors

Lacrimal gland dysfunction- following rat coronavirus- virus

damages the harderian gland (KCS)

dusty bedding predisposes to

aspiration pneumonia

Multinodular, granulomatous

inflammatory foci with chondrolysis and

invasion by mesenchymal cells

Large Granular Lymphocytic Leukemia

Splenomegaly with erythrophagocytosis

DDX- Lymphoma and histiocytic sarcoma

Splenomegaly, enlarged lymph

nodes, hepatomegaly

Cutaneous Lymphoma (mycosis fungoides)

circumscribed erythematous

plaques pregressing to ulceration

epitheliotropic/ medium to large size,

T cell lymphocytes and dissociated

adjacent epidermal cells

Histiocytic Sarcoma SD/ Wistar Rats

Mammary Tumors

Fibroadenoma

Carcinoima rare variety of patterns

Pituitary gland tumors

Chromophobe adenoma pars distalis

Testicular Tumors

Interstitial cell tumor F344 older males lobulated light yellow`

Mesothelioma F344

Zymbals Gland Tumors

Other

Liver, LN, Lung, Spleen, Mediastinum,

Retropertoneum

Vesicular nuclei, ample cytoplasm, MNGC

morphology varies from sheets to pallisading and

streaming fusiform cells

SD females; recurrence is likely

retroviruses not involved

circumscribed moveable firm lobular

mass

interlobular and intralobular

connective tissue

may consist of primarily connective tissue, or

epithelial cells predominate

majority/ SD/ Wistar rats

IHC required for positive identification

Prolactin secreting tumors most common;

may contribute to mammary tumors

polyhedral to elongated cells with granular

vacuolated cytoplasm

also have smaller cells with

hyperchromatic nuclei and scant

cytoplasm

concurrent hypercalcemia

Tunica vaginalis of testis

Holocrine gland at the base of the ear

circumscribed and ulcerated

sheets of epithelial cells with abundant

vacuolated cytoplasm, with necrosis and

leukocytes

adenoma or adenoacarcinoma

Polyhedral cells and acinar structures

containing keratinized material and debris

HamstersDNA Viral Infections

Non-envelopedAdenovirus

General Ileal enterocytes

EnvelopedHerpesvirus

Cytomegalovirus Acinar epithelium cytomegaly with INIB and ICIB

Parvoviridae

Missing incisor teeth

Polyomavirus

Transmissible Lymphoma Hamster Polyoma Virus can be papilloma like

Lymphoma liver, kidney, thymus

RNA Virus

Arenaviral infection

Paramyxovirus unknown significance

Sendai virus

Bacteria

Large amphophilic intranuclear inclusions,rarely

in crypts, asymptomatic

Salivary and Lacrimal glands

H-1: necrosis and inflammation of dental pulp with mononuclear leukocytic

infiltration of the dental lamina and osteoclasiss of

alveolar bone

New Strain: enamel hypoplasia,

periodontitis, suppuration and mineralization,

hemorrhage in dental pulp

Multifocal cerebellar and cerebral hemorrhage and thrombosis with

transmural hemorrhage

keratinizing skin tumors of hair follicle origin

Non glabrous skin- keratinizing follicular structures reminiscent of

trichoepitheliomas

Abdominal masses, large lymph nodes

usually lymphoid but erythroblastic, reticulosarcomatous, and myeloid types

have been described, sometimes plasmacytoid features

Lymphocytic Choriomeningitis (LCM)

chronic wasting, lymphocytic infiltration into the liver, lung, spleen, meninges, and brain

vasculitis and glomerulitis with Ag/Ab complexes in glomeruli

Zoonotic (mild influenza like to meningitis)

Pneumonia virus of Mice (PVM)

Interstitial pneumonia with consolidation

Segmental rhinitis --> necrotizing tracheitis and

bronchoalveolitis

antigen in respiratory epithelium

hyperplasia of epithelium follows infection plus peribronchiolar

lymphocytes

GRAM (-) Enteric

Campylobacter jejuni Zoonotic

Lawsonia intracellularis soiling of perineum

Tyzzer's Clostridium Piliforme intracellular

E coil

Helicobacter

Salmonella Embolic glomerulonpehritis

Gram (+) Enteric

Clostridium difficile

Non-Antibiotic-associated Clostridium difficile high fat diet

Gram (+) Respiratory

Corynebacterium kutscheri oral cavity, lymph nodes

Streptococcus pseumoniaeS. agalactia

Gram (-)

co infection with Lawsonia

Runted and emaciated hamsters

Segmentally thickened ileum with prominent serosal nodules and fibrinous peritoneal

attachments

marked crypt and villus epithelial hyperplasia, villus elongation

varying necrosis and hemorrhage, crypt abscesses, granulomatous

inflammation

Hepatic necrosis, Ileum , cecum, colon

focal granulomatous myocarditis with conspicuous bulging nodules

DDX: Salmonella, Coliform enteritis, Antibiotic associated C difficile,

Campylobacter

yellow to dark red fluid, blunting and fusion of villi,

lined by cuboidal epithelium

neutrophilic inflammation

focal necrosis fo liver, with neutrophils

DDX: Clostridium, Lawsonia, Salmonella

Gastric antrum and pyloric duodenal

junction

Gastric mucosal hyperplasia to dysplasia

may progress to carcinoma

Proliferative and dysplastic typhlocolitis

mucosal thickening and sibmucosal edema,

hypertrophy of enterocytes

Cholangiofibrosis (H Cholecystis)

Liver: Pinpoint necrosis, with thrombosis

Lung: hemorrhage, interstitial pneumonia, and thrombophlebitis

Spleen: focal necrosis and splenitis

Antibiotic -associated Enterocolitis

Lincomycin, clindamycin, ampicillin, vancomycin,

erythromycin, cephalosporins, gentamicin,

penicillin

cecum is distended with gas and tan to red

fluid contents

mild pseudomembranous typhlitis. Effacement of epithelium, edema

of LP, mucosal hyperplasia

DDX: Salmonella, Enteropathogenic E Coli, Tyzzer's dz

Necrotizing to hemorrhagic typhlitis

Cecal mucosal hypertrophy of Unknown etiology

ceca ar congested contracted and opaque

increased mitotic activity and hyperplasia of enterocytes

lining the crypts

local granulomatous and suppurative lesions

Francisella tularensis

Leptospira ballum

Yersinia pseudotuberculosis

Mycoplasma pulmonis

Mastitis

StrepP pneumotropica

E coli

Actinomyces bovisStaphylococcus aureus

StreptococcusPasteurella pneumotropica

Parasites

Ectopic Mites (Acariasis)

Demodex cricetiaurati

Notoedres notoedres

Notoedres cati

Myiasis

Wohlfahrtia vigilSarcophaga haemorrhoidalis

Musca domestica

Endoparasites

Spironucleus muris intestinal flagellate incidental findingCryptosporidium

Giardia misocricetus

Giardia muris mostly asymptomatic

Microscporidia

ruffled fur, lungs had mottled hemorrhage,

livers pale and seollen, spleens enlarged

Lymphoid necrosis and focal hemorrhages and bacteria

hemolysis, jaundice, nephritis, hepatitis

Chronic emaciation with intermittent diarrhea

Caseous nodules in intestine, mesenteric lymph nodes, liver, spleen, and lungs

Pasteurella pseumotropica and others

URI, Otitis, Bronchopneumonia

Cutaneous and cervical abscess

burrows in stratum corneum

Ornithonyssus bacoti and sylvarium

chronic lesions- thickening of SI cecum and colon

Encephalitozoon cuniculi

NematodesPinworms Syphacia criceti

S mesocricetiS obvelata more common

S murisTrichosomoides nasalis

TapewormsCysticercus fasciolaris (Taenia taeniaformis) dogs and cats

Rodentolepis microstoma Lower small intestineNana Lower small intestine

Hymenolepis diminuta upper small intestine

Stillborn or weak Vitamin E related/ deficiency

Diabetes Mellitus

DDX: trauma and cannibalism

Malocclusion

Periodontal Disease

Pugilism Females are aggressive Chinese hamsters

Cannibalism

Hibernation and Estivation

Nutritional and Metabolic Disorders

Spontaneous Hemorrhagic Necrosis (SHN) of the CNS of

fetal hamsters

Prosencephalon: Symmetrical, subependymal, vascular degeneration, with

edema and hemorrhage

intraventricular hemorrhage

strain related variations to susceptibility

Recessive in Chinese hamsters

Weight loss, glucose intolerance, hyperglycemia,

polyuria, polydypsia, hypoinsulinemia, ketonuria

Environmental Genetic and

Other Disorders

Bedding-associated Dermatitis

Wood shavings- footpads

degeneration and atrophy of the digits, with granulomatous

inflammation

necrosis and ulceration with foreign

body dermatitis

Congenital/ Hereditary Hydrocephalus

No obvious changes in behavior

doming of the calvaria was absent

stenosis of cerebral aqueduct

Inconsistent and permissive

Low temps, short days, solitude, nesting material,

inadequate food stores

high temps, low water may stimulate

estivation

Age related disorders

Amyloidosis (older animals) Females > Males

Atrial Thrombosis Left auricle and atrium

Alveolar Histiocytosis

Neoplasia

Lymphoma

epidermotropic

Adrenocortical adenomas

Hamster Glomerulopathy (arteriolar Nephrosclerosis)-

young animals

Gross: Pale granular with irregular cortical

depressions; radiating cortical scarring

Histo: Thickening of BM with eosinophilic material

may be concurrent amyloid in advanced

lesions

variable degeneration of tubules and minimal inflammatory

response, proteinaceous casts, fibrinoid change in vessels

Hamster female protein similar to Amyloid P

Gross: pale, irregular granular capsule, livers are swollen

Histo: Amyloid in glomeruli, tubular BM, portal triads, intestine

often associated with amyloidosis

bilateral ventricle hypertrophy is

common

focla to diffuse myocardial degeneration; medial

degeneration and calcification of coronary arteries

Polycystic Disease (polycystic Liver Disease)

Multiple Hepatic cysts in older hamsters

epididymis, seminal vesicles, pancreas, endometrium

Cysts are thin walled containing clear straw colored fluid lined by flattened to cuboidal

epothelium

pressure atrophy of hepatic cords, hemosiderin, proliferation of bile

ducts, periportal lymphocytic infiltration

Bile Ductular Hyperplasia/ Hepatic cirrhosis

spontaneous, uniform nodularity, periportal

fibrosis, bile duct proliferation

nodular hepatocellular degeneration, necrosis, and mixed leukocyte infiltration

Fibrinoid degeneration of arterioles

Polyoma virus or spontaneous

spontaneous tumors are Multicentric, thymus, lymph

nodes, spleen, liver

Cutaneous Lymphoma resmbling mycosis fungioides

GerbilsVirus

Reovirus type 3

Bacterial Infections

Tyzzer's Disease Clostridium piliforme

Clostridium difficile

Citrobacter rodentium goblet cell hyperplasia

Salmonella typhimurium diarrhea, dehydration high mortality

Group D

Staphylococcal dermatitis Staph aureus

Nasal Dermatitis S Aureus and S xylosus dermatitis and alopecia may become ulcerative

Bordetella bronchiseptica

asymptomatic

Leptospirosis not natural infection

Helicobacter pylori

Parasitic DiseasesDemodexGiardia Upper small intestine

degenerative lesions in pancreas and focal

necrotic lesions in the CNS

Multifocal periportal necrosis in liver with neutrophils and macrophages/ Focal fibrosis

Ileum and cecum, necrosis and

sloughing, blunting, edema, neutrophils and macrophages,

focal Peyer's patch necrosis, lymph node mecrosis, myocardial necrosis with myofiber collapse,

and leukocyte infiltration

diffuse suppurative encephalitis

DDX: Cl. Difficile, salmonella

Antibiotic associated enterocolitis

following Amoxycillin and Metronidazole

bloody diarrhea, thickening of the colon and rectum

testicular enlargement, focal hepatitis, splenic necrosis,

suppurative orchitis, interstitial pneumonia

pyogranulomatous leptomeningitis

gross- moist dermatitis of face, nose, feet, legs, ventral

abdomen

Histo- suppurative dermatitis with acanthosis and hyperkeratosis

porphyrin containing lacrymal secretions

have been an important contributing

factor

older animals are resistant, younger animals can have severe mortality

Ciliary Associated Respiratory Bacillus

Acute didsease- hemolytic anemia,

icterus, centrilobular liver necrosis, necrosis

of renal tubules

Chronic- Renal interstitial fibrosis, inflammation, cysts,

chronic gastritis, gastric ulcers, gastrointestinal

metaplasia, gastric adenocarcinoma

Pinworms no clinical problems

Tapeworms Rodentolepis nanaGenetic Disease

Epilepsy

MalocclusionBehavioral disease

Streptomycin Toxicity

Lead Toxicity

Amyloidosis filariid worm liver, spleen, lymph nodes

Obesity and diabetes

only bred animala

Age related disease

necrosis and fibrosis

Dentostomella translucida

no histopathologic lesions

twitching of vibrissae and pinnae, motor arrest,

myoclonic jerks, clonic-tonic siezures, vestibular

alterations

Periodontal disease and dental caries

Toxic and Metabolic Disorders

Direct neuromuscular blocking by inhibition of acetylcholine release

Chronic progressive nephropathy with acid

fast intrnuclear inclusions in renal proximal tubular

epithelium

Lipofuscin pigment granules in hepatocytes and Kupffer

cells

microcytic hypochromic anemia

with basophilic stippling

DDX: Age related glomerulonephropathy, and

erythrocytic basophilic stippling

reduced glucose tolerance, elevated

insulin, and hyperplastic or degenerative changes in the

endocrine pancreas

Hyperadrenocorticism/Cardiovascular disease

plaquesof intimal and medial ground substance with

mineralization of the aorta and mesenteric, renal, and

peripheral arteries

elevated serum triglycerides, enlarged pancreatic islets. Fatty

livers, thymic involution,

pheochromocytoma

focal myocardial necrosis and fibrosis

Focal myocardial degeneration

Chronic glomerulopathy

Aural cholesteatoma

Cystic ovaries

Ocular proptosis

NeoplasmsMongolian gerbils Ovarian

Adrenocorticalcutaneous

Granulosa cell tumorsDysgerminoma

luteal cell tumorsleiomyomas

thecal cell carcinoma

males, ventral marking glands

Other species

thymoma

Hodgkin-like lymphoma

adrenocortical tumorsprimary ovarian tumors

Helicobacter pylori Gastric carcinoma

glomerular hypercellularity,

thickening of glomerular basement membranes, tubular degeneration

with dilatation and cast formation, mononuclear

cell interstitial inflammation

Keratinized epithelium arising from outer

tympanic membrane and external auditoryt

canal

displaces tympanum into moddle ear with compression and secondary inflammation resulting on destruction of

temporal bone and iner ear

head tilt and keratin plugs in external ear

canal

ovulation and corpus luteum formation

continue

protrusion of the nictitating membrane and conjunctiva with

bulbar proptosis

Marking gland adenocarcinoma

Squamous cell carcinoma

Uterine adenocarcinoma

Guinea Pigs

Kurloff cells NK counterpart

normal

normal

Osseous metaplasia in lungs not significant

Thymus

DNA Viral InfectionsNon-enveloped

Adenovirus

Adenoviral Pneumonia

EnvelopedHerpesvirus

Cytomegalovirus CMV group

kidney cell cultures

Guniea Pig X virus (GPXV) isolated from leukocytes

RetrovirusCavian Leukemia Retrovirus Type C

RNA Viral Infections

finely granular cytoplasmic inclusions

found in spleen and bone marrow and

thymus

Pulmonary arterial medial thickening

Adventitial lymphocytes in pulmonary vesels

lamellar bone with varying degrees of calcification

degenerate thymocytes near Hassals corpuscles

Cardiac glycogenosis (Rhabdomyomatosis)

incidental degenerative condition and

congenital tissue malformation with

blastemoid features

pale pink poorly delineated foci or streaks mostly in left

ventricle

Low morbidity and mortality

consolidation of cranial lung lobes and hilus

necrotizing bronchitis and bronchiolitis with

desquamation of lingin epithelial cells and

leukocytic inflammation with fibrin

Intramuclear round basophilic 7-15 um

inclusions

DDX: Parainfluenza, cytomegalovirus,

bacteria (bordatella)

humans, primates, mice, rats, guinea pigs

Karyomegaly and intranuclear and intracytoplasmic

inclusions

Ductal epithelial cells, salivary glands, kidneys,

liver, lung

Guinea pig herpes-like virus (GPHLV)

focal hepatic necrosis and mortality

Arenavirus

Coronavirus-like Infection

Parainfluenza-3 (PI-3)

Paramyxovirus

Sendai virus

Picornavirus

Murine Poliovirus LamenessBacterial Infections

Enteric Infection

Clostridial disease Clostridium difficile enterotoxin recovered

necrosis of epithelium

Clostridium piliformeC difficile

Tyzzer's Disease Clostridium piliforme organisms in enterocytes

Lawsonia intracellularis

Salmonella typhimurium

enteritidis

Pseudotuberculosis

Lymphocytic Choriomeningitis (LCM)

lymphocytic infiltrates in the meninges, choroid plexi,

ependyma, and liver, adrenals, lungs,

Typical lesions and disease

interstitial pneumonia and alveolitis with

pulmonary congestion and hemorrhage, relative sparing of

airways

Pneumonia virus of mice

Murine Encephalomyelitis Virus

strain GDVII

Antibiotic Associated Dysbacteriosis (antibiotic

toxicity)

cecum atonic and dilated with fluid and gas,

mucosa is hemorrhagic and edematous

hyperplasia of the mucosa with

mononuclear cell infiltration on the LP

Spontaneous Clostridial Enterotyphlitis

Clostridium perfringens Type A

necrotizing ileitis and typhlitis, frequently

transmural

Adenomatous Intestinal Hyperplasia

intracellular bacteria in enterocytes

multifocal pale foci in liver and spleen

necrotizing fibrinous enteritis, colitis

granulomatous hepatitis, splenitis, lymphadenitis

Yersinia pseudotuberculosis

acute form: miliary cream-colored nodules in the

intestine wall in ileum and cecum

subacute to chronic: miliary caseous

nodules in mesenteric lymph nodes and

spleen, liver and lung

Respiratory Infection

Bordetella bronchiseptica

Citrobacter fruendii

Klebsiella

Pseudomonas aeruginosa sulfur granules

Streptobacillus moniliformis

Staphylococcus

Staphylococcus dermatitis

Streptococcus zooepidemicus group C suppurative lymphadenitis

S. pneumoniae

Bacterial SyndromesOtitis media S pneumonia

S zooepidemicusBordetella

PseudomonasBacterial Mastitis E coli

Klebsiella

mucopurulent or catarrhal exudate in

nares, nasal passages, and trachea

pleuritis, typanitis, chronic suppurative

bronchopneumonia, heterophilic, obliteration of

normal architecture

Guinea pig Inclusion Conjunctivitis

Chlamydophila caviae (formerly Chlamydia

psittaci)

red conjunctiva, purulent exudate, sloughed

epithelium, intracytoplasmic inclusioins and bacteria

pneumonia, pleuritis, enteritis

septicemia, necrotizing bronchopneumonia, pleuritis, pericarditis,

peritonitis, splenic hyperplasia

Pulmonary botryomycosis

cervical lymphadenitis, pyogranulomatous bronchopneumonia

Ulcerative pododermatitis (bumblefoot)

secondary to trauma, poor sanitation

plantar surface is swollen and painful

with necrosis

amyolid in the spleen, liver, adrenals and islets

in rare cases

erythema, hairloss, scabs, ventral abdomen

and extrematies

epidermal cleavage, parakeratosis

abrasions in oral mucosa

cervical lymph nodes, retrobulbar abscess, otitis

media, bronchopneumonia,

pericarditis

Diplococcal (pneumococcal) infection

no toxins, just resistant to phagocytosis

fibrinopurulent pleuritis, pericarditis,

peritonitis

bronchopneumonia with fibrin

ddx: Strep, Bordetella,

Strep zooepidemicusBacterial Conjunctivitis Chlamydia

Strep zooepidemicusStaph aureus

Pasteurella multocidaMycotic infections

Dermatophytosis

Microsporum canisParasitic Diseases

Ectoparasites

Acariasis Trixacarus caviae Sarcoptic mange

Demodex caviae

Pediculosis (lice) Gliricola porcelli Large biting lice

Gyropus ovalisEndoparasite

Protozoa Cryptosporidium wrairi juveniles

Eimeria caviae

Klossiella cobayae renal coccidiosis

Trichophyton mentagrophytes

scaly pruritic, alopecia, hyperkeratosis, epidermal

hyperplasia, pustules, folliculitis, arthrospores

inner thighs, neck , shoulders, abdomen

ortho and parakeratosis, heterophils, eosinophils,

flaccid paralysis, epidermal hyperplasia,

stratum corneum contains mites and eggs

pruritis, rough hair coat, alopecia

thin, potbellied, fecal staining, jejunum,

ileum, cecum

hyperplasia of crypt epithelium, edema of

lamina propria, necrosis and sloughing of

enterocytes, villous atrophy

intestine contains fluid, mucosa is congested,

edematous, with petechia

colonic hyperplasia, sloughing of

enterocytes, PMNS and mononuclear cells

micro and macrogametocytes

ddx: Crypto, clostridium,

dysbacteriosis

schizogony in endothelium of

glomerular capillaries--> rupture -->

schgizogony repeated in tubular epithelium

Gametogeny occurs in epithelium of Loops of Henle--> sporulated

occysts are released in urine

oocysts are ingested and invade intestinal capillaries--> kidneys

Toxoplasma asymptomatic

Helminth Baylisascaris procyonis

Paraspidodera uncinata asymptomatic

Scurvey Hypovitaminosis C

Encephalitozoon cuniculi

(microsporidiosis)

granulomatous encephalitis, interstitial nephritis

hepatitis, pneumonia, myocardial cysts, CNS

cysts

larval migrans- cerebral malacia, eosinophilic

granulomatous inflammation with nematode larvae

cecal worms up to 25 mm in length, also located in colonic

mucosa

Nutritional, Metabolic and others

deficient in L-gulonolactone oxidase (converts L-

gulonolacotne to L-ascorbic acid)

primates, guinea pigs, indian fruit bat, some birds, some fish, and

cetaceans

required for formation of hydroxyproline and

hydroxylysine in collagen molecules

deficient in interstitial and osteoid production

C is required for cholesterol to bile acid

formation

Lesions: Persistent primary spongiosa

(retained cartilage cores), and reduced osteoid production. Calcified

cartilgae is susceptible to microfractures

increased capillary fragility

enlargemnet of costochondral junction with hemorrhage;

proliferation of poorly differentiated fusiform mesencgymal cells in periosteal regions and

medullary cavity;; aggregates of eosinphilic mateiral

interspersed between the mesenchymal cells; dental anomalies- fibrosis of pulp

and derangement of odontoblasts

periarticular hemorrhage

widening of intercellular spaces between

endothelial cells, vacuolar degeneration and

depletion of subendothelial

collagenous tissue// Increased pro-thrombin

time

Necrotizing myopathy

Nutritional muscular dystrophy Vit E/ Se deficiency

Metastatic Calcification > 1 year old

end of pregnancy

Diabetes Mellitus

Alopecia back and rump

Malocclusion molar and premolars genetics and fluorosis

Gastric dilatation and vovlulus

hemosiderin laden macrophages in lamina propria of

intestine

increased susceptibility to streptococcus

pneumoniae (impaired macrophage migration

and heterophil phagocytosis)

idiopathic necrosis with leukocyte infiltration,

loss of cross striations, and mononuclear cell

infiltrate

DDX: nutritonal muscular dystrophy, spontaneous

muscular mineralization with degeneration

pallor of affected muscles, coagulative necrosis and hyalinization of myofibers,

fragmentation of sarcoplasm, increased basophilia of

sarcoplasm, rowing of nuclei, and regeneration

multinucleated muscle fibers may be present

in regenerating myofibers,

mineralization is not an important feature

testicular degeneration is a later development

Myocardial and Skeletal Muscle Degeneration with

mineralization

may be incidental finding

soft tissues around the elbows and ribs

lung, trachea, heart, aorta, liver, kidney, stomach, uterus,

sclera

low magnesium and high phosphorus(high Ca and P diets interfere with Mg

absorption)

Pregnancy Toxemia (Hepatic lipidosis with ketosis)

Fasting or Metabolic Form

acidosis, ketosis, proteinuria, ketonuria, low urine pH

(acidosis)

lowblood glucose, ketosis, hyperlipidemia

Circulatory or Toxic form (preecclampsia)

uteroplacental ischemia due to

compression of the aorta

placental necrosis, hemorrhage, ketosis, and

death, periportal liver necrosis, leukocyte,

nephrosis,

infectious agent unidentified

vacuolation of and degranulation of islet Beta cells with fatty infiltration of

the exocrine cells

advanced pregnancy and lactation

ddx: barbering, pediculosis,

dermatophyte

Cecal torsionIntestinal hemosiderosis lamina propriaFocal Hepatic necrosis Subcapsular considered terminal ddx: Tyzzer's

Liver contusions traumatic fractures

Behavior

Diseases of Aging

Segmental Nephrosclerosis interstitial lymhpocytes

Cystitis and urolithiasis

Ovarian cysts

Fatty infiltration of pancreas

Neoplasia'

Kurloff cells act as NK cellsHematopoietic

Cavian Leukemia

Chronic Idiopathic Cholangiofibrosis

Periportal fibrosis, hepatocyte

degeneration and interstitial fibrosis,

proliferation of cholangioles

Foreign body pneumonia (Pneumoconiosis)

aspirated food or bedding

granulomatous bronchiolitis, or pneumonia

Adjuvant associated pulmonary granulomas

Subcutaneous injections with Freunds

adjuvant

Lung: multifocal granulomatous inflammation

ddx: perivascular lymphoid nodules,

pneumoconiosis, focal pneumonia

ear chewing and hair pulling

irregular pitted granular cortices

pale linear streaks extend down into the cortex

interstitial fibrosis, tubular dilatation

Fecal contaminants such as E coli

thick bladder mucosa, congestion intraluminal

hemorrhage, mononuclear leukocytes, fibroblast

proliferation, urinary calculi

rete ovarii- large fluid filled cysts on the surface (cysts are

continous with follicles and mesovarium)

cystic endometrial hyperplasia, mucometra,

endometritis, fibroleiomyomas

large areas of adipose tissue between normal

panreatic acini

serum factor (Asparaginase) has anti tumor effects

gross- lymph node enlargement (cervical, axillary, mesenteric,

inguinal), Splenomegaly, Hepatomegaly,

Lymphoblastic cells in spleen. Liver, BM, interstitium of lung, thymus, alimentary tract, and lymphoid tissue, heart, eyes,

and adrenals

Reproductive tractOvary Ovarian teratoma

Granulosa cell tumorsUterus (benign) Uterine leiomyoma

Uterine fibromaUterus (malignant) Uterine myxosarcoma

Mammary

AdenomaRespiratory tract

Benign Papillary Adenoma bronchogenic originNasal Adenocarcinoma

Tumors of the skinTrichoepithelioms

PapillomasSebaceous adenoma

Penile papillomasLipoma

FibrosarcomaFibroma

Carcinoma

adrenocrotical adenomaInsulinoma neurologic signs

Rhabdomyomatosis

Other tumorsbile duct tumors

undifferentiated carcinomaLipoma

fibrosarcomahistiocytic lymphosarcoma

Uterine leiomyosarcoma

adenocarcinoma, ductal origin

Malignant mixed mammary tumor

Endocrine and Cardiovascular

Benign mixed tumors (myxoma) of the

Cardiovascular system

well differentiated mesenchymal

components like bone cartilage and fat

congenital condition characterized by

vacuolation of myofibers and glycogen

deposition

Rabbits

Order Lagomorpha induced ovulators

Appendix is the tip of the cecum

DNA Viral InfectionsNon-enveloped

Adenovirus

Adenoviral enteritis

EnvelopedPapillomavirus

2 rows of upper incisors, one right behind the other in the

upper jaw

Lab Rabbits descended from the

European Orytolagus cuniculus

Birthing is called Kindling

Cecotrophy- re ingestion of mucous coated "night feces"- high in protein and Vitamin B

complex

Erythrocytes 6.5-7.5 um, heterophils (9-15 um) with acidophilic

granules

Sacculus rotundus- spherical thickwalled enlargement at

the ileocecal junction

the adjacent cecum has around patch of

lymhpoid tissue called the cecal tonsil

(lymphocytes and macrophages in the lamina propria and

submucosa

the length of the duodenum has

Brunners glands

Urine contains Calcium carbonate crystals and triple

Phosphate crystals

Calcium is absorbed in proportion to diet and is

excreted in the urine rather than bile

Urine may be pigmented due to dietary porphyrins,

elevated urobilin (all non-pathologic)

Hematuria may be caused by

adenocarcinoma, uterine polyps,

episodic bleeding from endometrial venous

aneurysms, cystitis, or polyps

Hemoendothelial placentation, receiving antibodies through

placenta

duplex uterus with 2 hors and 2 cervixes

Bones are fragile, and light comared to muscle mass

Right chambers of heart are thin walled and may

contain post mortem clots with no contraction

associated with significant increases in

E coli

Virus was isolated form the intestinal wall and GI

contents, spleen, kidney, and lung

Rabbit (Shope) Papillomatosis frequently on eyes and ears

Oral Papillomatosis

Poxvirus

Myxomatosis (Leporipox)

Rabbit Pox

Polyoma virus

Parvovirus

Lapine Parvovirus

Herpesvirus

Benign in cottontails (Sylvilagus), but causes

Papillomas with progression to Squamous cell Carcinoma in

Oryctolagus rabbits (but no infectious virus is

produced)

Rabbit oral papilloma virus

pedunculated masses on the ventral aspect of the tongue and regress spontaneously

Basophilic intranuclear inclusions

Leporipoxvirus (indistinguishable from

vaccinia)

Proliferation of large stellate mesenchymal cells (myxoma cells) interspersed within a

homogenous matrix of mucoid material

hypertrophy and proliferation of

endothelial cells , and epithelium becomes

hyperplastic or degenerative

intracytoplasmic inclusions in the affected epidermis only (not

mesenchyme) and conjunctiva; Insect transmitted

South american type and Californian type

that causes lethal disease of

myxomatosis in European rabbit

(Orytolagus)

Rabbit (Shope) fibromatosis (leporipox)

related to Myxomaytosis and Hare

and Squirrel Fibroma viruses

benign self limiting disease in wildlife

transmissibel to European Rabbits (Orytolagus) and

cottontails

??Inclusions in the epithelium and mesenchyme??

Papules on skin with necrosis and hemorrhage,

oropharynx, respiratory tract, spleen, liver

Pockless form, hepatic necrosis, pleuritis,

splenomegaly, lymphoid necrosis

Rabbit kidney vacuolating virus

intranuclear inclusions in the renal tubular

epithelium

Legs and feet- Visceral metastasis in young animals,

fibroblast proliferation with mononuclear and PMN

infiltration

transient depression and anorexia with no

mortality

Epstein Barr virus analog

Herpes Simplex

Herpes-like viral infections

RNA Viral InfectionsCalicivirus

Rabbit Hemorrhagic Disease Fatal to Orytolagus, not Sylvilagus

Coronavirus

Coronaviral enteritis

Not a natural pathogen

Rotavirus

Rotaviral enteritis

Miscellaneous

Sendai virus

Rabies racoon variant rabiesBacterial Infections

Leporid Herpesvirus 1 (Herpes Sylvilagus)

Lymphoproliferative disease, lymphoid

hyperplasia to lymphosarcoma

Experimental model for herpes simplex

encephalitis

Non-suppurative meningoencephalitis with necrosis of neurons and

prominent intrnuclear inclusion bodies in neurons

and astroglial cells

Hemorrhage, hydropericardium

necrosis in spleen, dermis, lungs, adrenald, Intranculear eosinophilic to amphophilic

inclusions

DIC thought to play arole

bloody nasal discharge, pulmonary hemorrhage and

edema, hepatomegaly, splenomegaly, perirenal

hemorrhage, serosal ecchymoses

necrosis of hepatocytes with

hepatic dissociation, crypt necrosis,

pulmonary edema, hemorrhage, necrosis

of lymphocytes, erythrophagocytosis in

spleen

small and large intesitne, enterocyte

necrosis, villous blunting, mucosal

edema, inflammation

Pleural effusion disease and Cardiomyopathy

lymphoid depletion of spleninc follicles, focal

degenerative changes in the thymus, and lymph nodes,

proliferative changes in glomerular tufts and uveitis

myocardial degeneration and

necrosis

similar lesions to coronavirus

Upper respiratory tract following intestinal

innoculation

Bordatella bronchiseptica

Asymptomatic usually lymphoid hyperplasia

Enteritis Complex5-12 week old rabbits Multi-factorial

RotavirusCoronavirus

Clostridium perfringens Type E Iota toxin

difficile

spiroforme most common

E coli

Respiratory Bacterial Infections

Pasteurella multocida Serotype A and sometimes D

Snuffles, atrophic rhinitis, otitis media,

conjunctivitis, bronchopneumonia, abscessation, genital infections, abortions,

chronic rhinitis- catarrhal to mucopurulent exudate,

turbinate atrophy

Suppurative otitis media, with squamous metaplasia of tympanic

bulla lining

Bronchopneumonia- cranioventral to acute necrotizing fibrinopurulent

bronchopneumonia; chronic bronchitis with peribronchial lymphocytic inflammation, alveolitis with heterophils

predominating, multinucleated giant cells, pleuritis

pyometra, salpingitis, perioophoritis,

necrotizing metritis// Acute septicemia,

meningoencephalitis

suppurative bronchopneumonia and interstitial pneumonia

peribronchial and perivascular cuffing

Cilia-Associated Respiratry Bacillus

typical findings for all: submucosal edema,

hemorrhage, ulceration and

fibrinous exudate- necrotizing typhlitis

disruption of normal gut flora predisposes

damage to enterocytes, profuse diarrhea, dehydration and death

Enteropathogenic strains (attaching and

effacing)

serosal ecchymoses, edema of the walls of the cecum and colon, edematous mesenteric

lymph nodes, prominent lymphoid tissues in Peyer's

patches and sacculus rotundus

Small and large intestine: Rods and

cocci lining the villi, villi often blunted, lamina propria is edematous

and infiltrated by heterophils

o153, o145

Lawsonia

SalmonellaVibrio

Coccidia

DDX: listeriosis and staph (liver)

Klossiella pneumoniae hemorrhagic enterotyphlitis

Salmonella

Vibrio

Mucoid enteropathy

Other Bacteria

Listeriosis

Staphylococcus aureus

Acute septicemic form

Enterohemorrhagic Strains (EHEC)

cecal and colonic edema, serosal

hemorrhage

sloughing of enterocytes, vasculitis, edema, heterophils- Hemolytic uremic syndrome-

fibrinous vasculitis in interlobular blood vessels, swelling of

glomerular tufts with leukocytic infiltration, glomeruli had swelling and fibrin deposition in capillaries

Proloiferative enteritis/ histiocytic enteritis

Suppurative and erosive to proliferative with hyperplasia of enterocytes lining crypts and villi with mononuclear

infiltration

histiocytes with abundant granular

cytoplasm and MNGC. PAS positive granular

material (degrading bacteria)

Silver and PAS stains show apically located epithelial bacteria

Clostridium piliforme (Tyzzer's Disease)

serosa- fibrin on cecum and colon

thickened and edematous, multifocal necrosis in liver

and myocardium, transmural necrosis in cecum and colon

intracytoplasmic bacteria

rarely associated with disease, normal

inhabitant

S typhimurium and enteritidis

Synonyms: mucoid enteritis, bloat,

hypoamylasemia

teeth grinding, cecal impaction, gelatinous mucus

in colon

Stomach distended with fluid and gas.

acute fatal disease, focal hepatitis, ascites, enlarged mesenteric

lymph nodes

death typically is in advanced pregnancy

Newborns may develop systemic

listeriosis, stunting, meningoencephalitis

straw colored fluid in the abdominal cavity. Miliary pale foci

of suppurative hepatitis in liver. Placenta is thickened with friable

surface

Chronic suppurative lesions

skin, mammary gland, genital tract, conjunctiva, footpads, upper and lower respiratory

tract.

ddx: Pasteurella, Listeria, and Tyzzers

suckling kits, multifocal suppurative lesions in the skin, lung, kidney, spleen,

heart, liver

Mastitis swollen, red

Respiratory

Pododermatitis sore hocks

Treponema paraluiscuniculi Venereal spirotrichosis

Helicobacter unknown significance

Yersinia pseudotuberculosis

Necrobacillosis Schmorls Disease

Streptococcal septicemia young rabbitsDiplococcal

Mycotic Infections

Dermatophytosis

Aspergillus

ddx: Staph, Pasteurella, Streptococci

mucopurulent rhinitis and localized bronchopneumonia

and abscesses

vulva, prepuce, anal, muzzle, periorbital

edema, erythema, papules at

mucocutaneous junctions

Syphilitic lesions progress to ulceration and crusting;

Microscopically- hyperplasia of epidermis, necrosis of epithelium,

erosions, ulcerations, plasma cells, macrophages, heterophils,

focal caseation necrosis of liver spleen, cecum, LN and reproductive

tract

dermatitis secondary to moist skin, in dewlaps, excessive

environmental moisture, malocclusion, panting

lesions are suppurative with

erosion and ulceration

Corynebacterium pyogenes cause

ulcerative skin lesions

Trichophyton metagrophytes

head and ears, paws, alopecia, crusting raised

hyperkeratosis, epidermal hyperplasia,

folliculitis, mononuclear and

polymorphonuclear cells

DDX: idiopathic molts during nest building, Barbering

pulmonary granulomas, well circumscribed, central coagulation

necrosis

Pneumocystis carinii

Parasitic Diseases

Coccidia Intestinal

Heaptic Eimeria steidae

Encephalitozoon cuniculi

Cryptosporidium cuniculus usually asymptomatic occasional bluning of villi

Toxoplasma gondii clinical disease is rare

Pinworm Passalurus ambiguus adults in cecum

Pulmonary edema, congestion of alveolar

vessels, thickening and hypercellularity of

septaw, mononuclear and PMNS

Eimeria intestinalis, Eimeria flavescens,

Ingested sporulated oocysts release

sporozoites invade enterocytes and

multiply (Shizonts) --> Gametogeny -->

Oocysts

Sexual life cycle causes destruction of enterocytes and

cells of the lamina propria. Cecotrophy does not infect because the oocyst require sporulation at room temp

overnight

Sporozoites invade duodenal mucosa and spread systemically, migrate to liver via

mononuclear cells and invade bile duct

epitheliium where schizogony begins-->

gametogeny--> oocysts released in to

bile ducts

Liver: raised linear bosselated areas, yellow to grey

circumcsribed areas, gall bladder thickened and contains flocculent

material

Histo: Periportal fibrosis, dilation of bile ducts, mixed

inflammation, hyperplasia of bile

epithelium with papillary projections

lined by reactive epithelial cells

overlying collagenous tissue stroma

Obligate intracellular microsporidian parasite

"infectious motor paralysis" can infect mice, guinea pig, ssquirrel monkey, cat, dog

Usually subclinical in rabbits, and renal

lesions are incidental findings

Spores shed in urine, transplacental infection can occur, oral or respiratory transmission is

common. Spores travel via monocytes hematogenously, targets are lung, liver, kidney

Kidney: Focal irregular depressed areas- Granulomatous

nephritis

Lung, liver, CNS also granulomatous lesipons

1.5 x 2-5 um spores in epithelial cells,

macrophages, or free in the interstitium

In chronic renal lesions there is fibrosis and collapse of the

parenchyma

Phacoclastic uveitis and cataracts

may have multiple foci of necrosis and granulomatous

inflammation in lung, liver and spleen

Bylisascaris procyonis cerebrospinal disease

NematodirusTrichostrongylus

Psoroptes cuniclui

Cheyletiella parasitovorax

Sarcoptes scabei

Notoedres catiListrophorus gibbus

Aging and Miscellaneous

Hair Chewing (Barbering)

Hatch Burn

Physical injury

Ulcerative Pododermatitis

torticoolis, ataxia, circling, opisthotonus

Gross- Raised white nodules in

subepicardial and subendocardial

locations and liver serosa

Histo: Pyogranulomas/ eosinophilic granulomas; In CNS lesions are in the grey and white matter. Mostly in the brain stem

and cerebellum. Malacia, astrogliosis, gitter cells

Nematode larvae have excretory

columns and lateral alae

Taenia pisiformis (Cysticercus)

Multiple or single white noduels, necrotic

centers with inflammation and

fibrosis

Obligate non burrowing mites

Proliferative and hyperkeratotic otitis externa with euxdation mostly oily

Dorsal trunk, scapula, ventral abdomen

Burrowing mites in the superficial epidermis

(Parakeratotic) hyperkeratosis, seborrhea

and hair loss, face, nose, lips, feet, abdomen, external

genitalia

pruritis and self mutilation is common

patchy alopecia on face and back, young group

housed rabbits

Boredom and low roughage diets have been implicated

Urine scalding of the perineum- hyperemic and excoriated with

serous exudate

Exfoliative Dermatosis and Sebaceous adenitis

non-pruritic scaling dermatitis with patchy coalescing alopecia

histo- Hyperkeratosis, interface dermatitis and

folliculitis, reduced sebaceous glands and

perifollicular fibrosis

One case was associated with a

thymoma

circumscribed ulcerative area covered by

granulation tissues

Poor sanitation, trauma, and wire cages are implicated

staphylococcus is most frequently

implicated

Prolapse of the deep gland of the third eyelid

may be due to laxity in the supporting

connective tissues

Vertebral fracture

incidental findings

Gastic Pyloric Hypertrophy

Intestinal Plasmacytosis

Chronic Renal Failure

Renal Amyloidosis sparing of the gloeruli

Vitamin E deficiency

Hypervitaminosis D

Hypo or Hyper Vitaminosis A

Pregnancy toxemia

can lead to incontinence

Site is usually lumbosacral L7 with hemorrhage around the

psoas muscles

Tracheal injury following intubation

Erosive to ulcerative tracheitis

Gastric Trichobezoar (Hairball)

predisposing factors include excessive grooming and hair

chewing due to boredom

Insufficient dietary roughage, poor gastric motility, and sedentary

lifestyle are more important

Marked muscular hypertrophy with

interference with gastric emptying

Marked plasma cell infiltration in the intestinal tract

usually asymptomatic, frequently in animals used for

antibody production and cholesterol studies

Cardiomyopathy associated with Ketamine/Xylazine/

detomidine

Multifocal myocardial degeneration with interstitial fibrosis

Attributed to ischemia secondary to vasoconstriction with reduced coronary blood

flow

Metastatic mineralization of the

aorta

Nutritional muscular dystrophy

neonatal mortality and infertility

pale mineralized streaks in muscle

Calcium and Vitamin D deficiency

Osteomalacia, overgrowth

Medial degeneration and mineralization of

major arteries, glomerular tufts, tubular

BM

In long bones there is depostion of basophilic

material (osteoblasts) on the periosteal and endosteal

surfaces

Poor ceonception, congenital

abnormalities, fetal reabsorbtions

Microencephaly, hydrocephalus, cleft palate

Mobilization of fat deposits leads to

metabolic acidosis and ketosis with fatty liver

Obesity, hereditary, imparied blood flow, pituitary

dysfunction all predisposing factores

Lead Toxicosis

Hereditary Disorders

Malocclusion

Neoplasms

Uterine Adenocarcinoma

Lymphosarcoma

Thymoma

Anemia, tremors, and posterior ataxia

Myocardial degeneration, hepatic necrosis, renal tubular degeneration,

hemoglobin casts

Congenital Glaucoma (Buphthalmia)

New Zealand White Rabbits

Enlargement of 1 or both eyes with corneal opacity

Autosomal recessive, Absence or

underdevelopment of the outflow channels

with incomplete cleavage of the

iridocorneal angles

Autosomal recessive, the mandible is long in relation to the maxilla

overgrowth of premolar and molar teeth also occur (seen in animals with diet deficient

in calcium and vitamin D)

Endometrial Venous Aneurysms

Persistent urogenital bleeding, clotted blood

in uterus

Blood filled endometrial varices consisting of dilated

thin walled veins

Most common spontaneous neoplasm

in Oryctolagus cuniculus

Nodular frequently multicentric enlargements of

one or both uterine horns

Cauliflower like surface and central

ulcerations

Serosal implantation and metastasis to the lung and liver

Leukemia only occasionally occurs

In cottontail has been associated with Herpesvirus

sylvilagus

Kidney and gastric mucosa most common sites, confined to renal

cortex

Liver is enlarged, pale, and swollen, spleen is large and lymph

nodes large

Stomach wall is thick with irregular plaques

and mucosal ulceration

Aside from thymic involvement there may be variable lymphocytic infiltrates in the other

organs like, lymph nodes, liver, heart, and

lungs

1 case of hypercalceima and exfoliative dermatitis

Prolactin-producing Pituitary Adenomass with Associated

Mammary Dysplasia

Swelling of 1 or more mammary glands with

enlargement and discoloration of the teats, thinning of

haircoat

Dilated cystic ducts lined by flattened cuboidal epithelium

with papillary projections

Common Mice StrainsCommon Diseases

C57BL/6 (B6) Hydrocephalus

Hippocampal neurodegeneration

Microphthalmia

Anophthalmia

cochlear degeneration- age related

malocclusion

Pulmonary proteinosis- aged

epithelial hyalinosis

amyloidosis- late onset

lymphoma

hemangiosarcoma

pituitary adenoma

BALB/ c or cBy Dystrophic epicardial mineralization

myocardial degeneration

auricular thrombosis

corneal opacities

conjunctivitis and blepharitis

periorbital abscesses

resistant to amyloidosis

normal hepatic lipidosis

lung adenomas

lymphoma

Harderian gland tumors

adrenal adenomas

C3H/ He corneal opacities

Hearing loss

myocardial degeneration

alopecia areata (HeJ)

Back ground strain, longevity

Melanism- coat color, heart valves, splenic capsule ,

meninges

barbering- with alopecia and Staph dermatitis

Albino,Pugilistic males

Hypocallosity (aplasia of corpus callosum)

Myoepitheliomas of salivary, preputial, and other exocrine glands

Agouti, Blind (rd1 mutation)

focal myocardial and skeletal muscle mineralization

hepatocellular tumors

129 mice

Pulmonary proteinosis

epithelial hyalinosis

Megaesophagus

conjunctivitis and blepharitis

lung tumors

Harderian gland tumors

Ovarian tumors

hemangiosarcoma

FVB/ N Siezures

persistent mammary hyperplasia

lung tumors

pituitary adenoma

Harderian gland tumors

Liver tumors

lymphoma

pheochromocytoma

amyloidosis- late onset

retinal degeneration

lymphoma

Pulmonary adenoma

Liver tumors

pituitary adenoma

hemangiosarcoma

Murine Mammary tumor virus- induced mammary tumors

Embryonic stem cells; variation in coat color and

behavior

Hypocallosity (aplasia of corpus callosum)

Testicular teratomas (embryonal carcinomas)

Swiss Mice, blind (rd1)

adenoma of prolactin secreting cells of anterior pituitary

Outbred Swiss Mice