J. Jill Heatley DVM MS DABVP (Avian), DACZMAssociate Professor, Zoological Medicine

College of Veterinary Medicine & Biomedical Sciences Texas A&M University, College Station

Gray... Western - Sciurus griseus Eastern – Sciuris carolinensis Arizona ...Sciurus arizonensis

Tassel-eared...Sciurus aberti Fox

Eastern Fox....Sciurus niger Apache Fox.....Sciurus apache

Tamiascirus American Red.....Tamiasciurus hudsonicus Chickaree......Tamiasciurus douglasi

Flying Squirrels – Northern Southern and Glaucomys volans

Order Rodentia Family Sciuridae

All continents Except Antarctica, Australia 50 genera, 273 species Subfamily

Cyonomys – Prairie Dogs Spermophilus – Ground squirrels Marmota – Marmots Ammospermophilus – Antelope Squirrels Tamias – Chipmunks Tamiasciurus – Chickarees Sciurus – Tree Squirrels Glaucomys – New World flying squirrels

Expanding urban communities Parks, neighborhoods

Bird feeders Nature Vacation Exotic Pets Research Rehabilitation Hunting

Bacterial Fungal Parasitic Viral Prion

Literature review

Toxoplasma gondii Intermediate not

definitive host Cryptosporidium parvum

Eastern gray squirrel Chipmunk Red squirrel California Gray squirrel

Hymenolepis nana Dwarf tapeworm of hamsters Human enteric disease

Praziquantel Mange in squirrels is

generally notoedric or demodectic and not transmissable to humans

Zoonoses Squirrel Disease

Lyme Disease Epidemic Typhus Tularemia Plague Leptospirosis Rat Bite fever

Squirrel Bite fever Streptobaccillus

moniliformis Spirillum minus

Red legged ground squirrel

Xerus erythropus Nigeria

Campylobacter spp. Salmonellosis Pasteurella multocida

Red squirrel Yersinia pseudotuberculosis

White tailed antelope squirrel Citellus lecurus

Yersinia enterocolitica Grey squirrel

Tularemia Isolated in 1912

Plague like disease of rodents Plague foci search

Bacterium tularense Francisella tularensis Tulare county of origin, CA Ground squirrels Spermophilus beecheyii

Zoonoses Sciurus carolinensis

Infant Bite Arkansas Prairie Dog (BT Cyonomys ludovicianus)

Titer positive 3 y with bite

Fox Squirrel Skinned/dressed

Magee JS et al. Tularemia trans by Squirrel Bite. Pediatric Infect Dis J.1989Feb8(2):123-5.

Avashia SB at al Emerging Infec Dis 10(3) March 2004

Kirkwood T. Tularemia from the Fox Squirrel JAMA 1931; 96(12);941-942

Leptospirosis Multiple species

Isolations - serovars Gray squirrel - ballum Fox squirrel - grippotyphosa

Zoonosis Leptospira kirschneri

Southern Flying squirrelGlaucomys volans

Exported to Japan28 29 yo males

Borrelia burgdorferi sensu latu Spirochetal bacteria

Most common tick borne disease Debilitating chronic infection Tick intermediate

Reservoirs Western Gray squirrel Eastern chipmunk

Tamias straitus – eastern & upper midwestern US Persistent infection, no clinical signs Ixodes scapularis

European reservoir potential Gray squirrel Sciurus carolinensis European tree squirrel – S. vulgaris

Bacterium Rickettsia prowazekii

Clinical Signs Fever, Headache, Muscle

pain Rash – trunk spreads to

extremities Doesn’t involve the palms or

soles (cf RMSF) Mort ~ 40% if untreated

Primary Vector Human Body Louse

Sporadic cases in Eastern US since 1970s Most cases in winter when squirrels nest in

attics All non fatal, humans faster recovery with

antibiotics Flying squirrels

Glaucomys volans Handled, squirrels nests, pets in home

Capable reservoirs Transient inapparent infection Squirrel human transmission unknown

Sucking lice (Neohematopinus sciuropteri)

Fleas transmit to squirrels in lab Direct contact, inhalation of dried

squirrel excretions bites of squirrel ectoparasites

Sucking lice Flea

Bacterium - Yersinia pestis Complex flea rodent cycle

Sylvatic reservoir Human clinical signs

Severe disease Fatality rate > 50% if untreated Rare - Dozen cases / year

Semiarid West New Mexico Arizona Colorado California

Periodic plague outbreaks Flea vector (Flea control!!!) CS: nonspecific: lethargy, depression, respiratory

distress, lymphadenopathy, anorexia Serologic testing

More susceptible rodent hosts Prairie dogs

Known reservoir Ground squirrels Fox squirrels

Human exposure occurs during outbreaks Flea bites Direct contact w nonrodent hosts

Trend of eastward expansion Epizootic fox squirrels central Texas

Dermatophytosis Sporotrichosis

Sporothrix schenckii Unknown Sciurid, not captured

Bite 1.5 months earlier in the park Severe arm lesion responded to 3 months of

antibiotic and antifungal therapy

Lymphocutaneous Sporotrichosis Associated with a Squirrel Bite: Case Report and Review PS Saravanakumar, P Eslami FA Zar Clinical Infectious Diseases, 23(3)3 Sep 1996) 647-648.

Dermatomycoses, Tinea, “Ringworm”

May accompany parapox fibromas

Systemic Phycomycosis Circular shape, scaly raised

border Patchy hair loss

Neck , head ,armpits, abdomen

Skin reddening, thin layer serous exudate, crusts, skin nodules

Hair broken off at skin surface,

Fine stubble broken hair

Lesions Etiologies

Lewis et al. JWD

Oct 1975 Urban

Gray squirrel

mycology

Trichophyton mentagrophytes Mucor Candida albicans Microsporum gypseum, Scopulaiopsis brevicaulis Microsporum cookei Systemic Phycomycosis Dermatiaceous Fungi –

pigmented Phaeoannellomyces wernecklii

Damp weather conditions Prevalence > 50%

Rule out Alopecia Sciurus carolinensis Glaucomys volans

Dietary, heritable? Congenital Alopecia Dermatophytosis Louse Bite Lesions Notoedric Mange Larval Harvest Mite Lesions

Histology Fungal organisms in superficial

skin, in and around hairs History, Lesions Direct examination Culture

Identify specific fungus Zoonotic

Young animals more commonly affected

One researcher developed lesions after handling squirrels

Use gloves, wash with soap after handling

White et al. Micro Study of Urban Gray squirrel 1975 JAVMA 167

Lymphocytic Choriomeningitis Virus Gray squirrels serologically positive UK 4/19

Snowshoe hare virus (SSHV) Arboviruses

West Nile Virus Western Equine Encephalitis

Lacross Virus Eastern Equine Encephalitis

Rabies Gray squirrel No human cases associated with squirrel bite

Monkeypox Virus Encephalomyocarditis virus

Alphaviruses, Togaviridae WEE rare disease in people

Lacrosse Virus, EEE (mort 50%), VEE rare serious disease Mosquito vector

Hosts (Black tailed jack rabbit, White footed mouse?, ?) Lacrosse Encephalitis –

Tree squirrels and chipmunks primary amplifying hosts WEE Viremia –

Gray squirrels (Sciurus carolinensis), California ground squirrels, San Joachin antelope ground squirrels, Aggressive, bite people, Usu fatal, may survive overwinter

Richardson’s ground squirrels (Spermophilus richardsonii) contaminated urine, cannibalism Experimental Infection

Weak, depressed, ataxic, limb paralysis prior to death Some became hyperexcitable Brain, brainstem Necrosis & edema

EEE - Gray squirrels Peripheral inoculation: Encephalitis & death

VEE – Significant viremia, > 50% mort Mexican ground squirrel - Spermophilus mexicanus Gray squirrel

Bunyaviridae Variant of the La Crosse virus Encephalitis occasional - NY, Eastern Canada

Antibodies Experimental infection ground squirrels

Symptomless viremia Artic ground squirrels

Spermophilus parryii Golden mantled ground squirrels

Spermophilus lateralis Yellow-pine chipmunks

Eutamias amoenus Red squirrels

Encephalitis virus Fox squirrel (Sciurus niger)

Seroconversion late summer early fall None in urine, fleas Exp: feces and oral cavity

Experimental infection suggests amplifying host High seroprevalence

Western gray squirrel (S. griseus) Eastern gray squirrel (S. carolinensis)

3/36 live neurologic tree squirrels viremia similar to WNV-infected birds. Most squirrels no virus in serum S. carolinensis

not amplifying hosts low viremias, lack of mortality Low seroprevalence 2% Useful as sentinels High seroprevalence

Tick borne encephalitis flavivirus complex 1956 epidemic of people and monkeys

Fever, hypotension hepatomegaly,

hemorrhage/neuro/bronchopneumonia recovery/late fever

Southern india - 2500 m radius Striped palm squirrels

Funambulus tristriatus Antibodies Viremic infective for Ticks

Orthopox virus Broad primate host range includes humans

Fever rash resembles small pox Low mortality high morbidity

Infection via direct contact Main host African tree squirrels

Tree squirrels Heliosciurus rufobrachium H. gambianus

Rope Squirrels Funisciuris anerythrus F. lemniscatus

Prairie dogs Poorly competent host Effective transmitters for veterinary staff

Diseases Infectious Monkey Pox

Humans 1-10% mortality Contact, respiratory droplets CS: fever, cough, conjunctivitis,

lymphadenopathy, nodular rash No treatment Strict biosecurity, humane

euthanasia CDC website

www.cdc.gov/ncidod/monkeypox Final rule prohibits

capture, offers to capture, transport, sale, barter, exchange, distribution, or release of a listed animal into the environment. Prairie dogs (Cynomys sp.) African Tree squirrels (Heliosciurus

sp.), Rope squirrels (Funisciurus sp.), Gambian giant pouched rats

Cricetomys sp.

Squirrel brains Creutzfeldt-Jakob disease (CJD)

“burgoo” Squirrel brain stew

5 patients 56-78y Unrelated, Different towns

Rural Kentucky Don’t eat brain unless you want

be a zombie

Summary Squirrels are harbor a plethora of zoonoses

Sentinel Is it the cute factor? Thanks for your attention

Field Manual of Wildlife Diseases in the Southeastern United States, 3rd ed Davidson, WR

Zoo & Wild Animal Medicine 5th edSainsbury, Rodent Chapter

Infectious Diseases of Wild Mammals ES Wiliams, IK Barker

Smithsonian Museum of Natural History North American Mammals http://www.mnh.si.edu/mna/main.cfm

Clostridium botulinum Saravanakuma PS Eslami P Zar FA Lymphocutaneous sporotrichosis associated with

a squirrel bite: case report and review. Clin Infect Dise 1996 sep 23(3) 647-8

Squirrel Fibroma AKA Squirrel Pox

Squirrel Pox Virus 1953

Leporipoxvirus Related to Shope’s Fibroma of rabbits

Range Range: Maryland, New York, Virginia,

Michigan, North Carolina, Ontario Host

Gray squirrel Fox Squirrel Red squirrel

Significant cause of decline Experimental infections

Woodchucks, rabbits

Squirrel Fibroma Lesions

Limited to skin Metastasis to the lungs, liver, kidney, and lymph nodes has

been reported. Secondary infection Vision obstruction

Raised flattened nodules Light colored, little fur 1/16- 1 inch diameter Single or wide dissemination Epizootic

Lesions on the eyelid Swelling, discoloration, necrosis of leg or foot

Clinical Signs Most infections self limiting, spontaneously regress Debilitation, emaciation, death Rare epizootics

Morbidity, mortality many squirrels Florida

www.michigan.gov/dnr

Parasite-mediated competition Parapoxvirus: Grey

& Red Squirrels Mosquito

spread