rna viruses of animals. viral classification taxonomy order (-viridae) family (-viridae) subfamily...
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RNA Viruses
of Animals
Viral Classification
Taxonomy Order (-viridae) Family (-viridae) Subfamily (-virinae) Genus (-virus) Species
Group III (ds) IV (+ss) V (-ss)
RNA Virions Cytoplasm:
Replication Biosynthesis
Helical capsid Most enveloped
with spikes NA
Double sense Single sense (+ / -) 2 single sense (+)
Viral Entry into Cells
Group III: dsRNA Reoviridae
REOVIRIDAE
REO=Respiratory Enteric Orphan Virus
Non-enveloped Icosahedral RNA ds Segmented Human Diseases
Rotavirus Coltivirus
Rotavirus World wide infection Fecal-oral spread Incubation: 1-3 days Diarrhea Children Diagnosis
ELISA Latex Agglutination
Prevention Hygiene Water sanitation
Coltivirus Colorado Tick
Fever Disease
• Acute• Myalgia• Photophobia• Rash• Hemorrhage
Tick vector Rodent reservoir
RNA ss (+); (-); & retro-
Group IV: +ssRNA nonenveloped Picornavirus
Rhinovirus Enterovirus Hepatovirus
Calicivirus Astrovirus Hepevirus
Hepevirus (formerly calcivirus)
+ss RNA nonenveloped Icosahedral Fecal-oral Domestic pig
reservoir Developing
countries/sanitation Hepatitis E
(enteric hepatitis)
ASTROVIRIDAE Astro = Star Nonenveloped +ssRNA 7 Human Serotypes Diarrhea Treatment
Supportive
CALICIVIRIDAE
Calicus Cup shaped Indentations
Non-enveloped Icosahedral Linear ss + RNA Human Diseases
Norwalk Virus(Norovirus)
Calicivirus
Norwalk Virus Summer diarrhea Epidemic Gastroenteritis V/D Institutions ID virus in stool 90% of viral
diarrheas
PICORNAVIRIDAE Pico = small Nonenveloped Icosahedral RNA + ss Human Diseases
Enterovirus• Polio• Coxsackie A , B• ECHO
Rhinovirus Hepatovirus
Rhinovirus
Common cold virus: 50%
Transmission: inhalation Incubation: 1-3 days Symptoms
Sore throat Mucopurulent nasal
discharge Complications
predispose to secondary bacterial infections
Hepatovirus: Hepatitis A Infectious Hepatitis Milder disease than
Hepatitis B No chronic form Fecal-oral Incubation: 2-5 weeks Virus excreted in stool Resistant to
disinfection Dx: IgM
Enterovirus
Disease Groups Poliovirus Coxsackie A, B Echovirus
Fecal-oral Cytolytic
GI mucosa Lymphatic tissue
Echovirus ECHO=
Enteric Cytopathic Human Orphan
Fecal-oral route Disease
Meningitis Paralysis URTI Myocarditis Fever Rashes Orchitis
Coxsackie A and B Fecal-oral Disease
Coxsackie A• Skin Rashes• Herpangina
• Mouth• Pharynx
• Hand/Foot/Mouth• Conjunctivitis• +/- DM Type I cause
Coxsackie B• Myocarditis• Meningitis• URTI• Paralysis
Poliomyelitis 3 serotypes (Type 1 disease) Transmission: fecal-oral Throat ->LN->Ileum->Blood-> CNS Phases
Asymptomatic: 90% Minor Polio Non-paralytic Paralytic: 2-3%, causes 75% of paralysis
Dx: virus in feces, secretions Prevention: Vaccine
Salk (IPV, killed) Sabin (OPV, modified live)
Poliovirus
Post Polio syndrome
BulbarPoliomyelitis
Group IV:+ssRNA enveloped
Togavirus Flavivirus Coronavirus
CORONAVIRIDAE Corona = crown Enveloped Helical Linear RNA + ss Respiratory droplet Human Diseases
Common cold (20%)
SARS
Severe Acute Respiratory Syndrome (SARS)
Respiratory Droplet Direct Indirect
2-10 day incubation Cough->Pneumonia Stable in environment
for days Dx: PCR Tx: supportive Prevention
avoid contact disinfect
TOGAVIRIDAE Toga = coat Spiked envelope Icosahedral Linear ss+RNA ~Arthropod vector Human diseases
Encephalitis • (VEE, WEE, EEE)
Rubella
Encephalitis: VEE, WEE, EEE
Rodent: VEE
all
Togavirus: Rubella Rubella
German Measles Respiratory Droplet 2-3 week incubation Rash: 3 days
• Facial• Spreads to body• Changes hourly
Complications• Adults
• Arthritis• Encephalitis
• Congenital defects• Nervous• Heart• Blindness
Prevention: MMRRubivirus
FLAVIVIRIDAE Flavus = yellow Enveloped Helical Linear RNA ss + Human Diseases
Hepatitis Encephalitis Hemorrhagic Fever
Flavivirus Hepatitis C
• HCV• Non A non B
Endemic Parental
• Blood• Needles• Organs
6-8 week incubation Mild form Chronic
• Cancer• Liver failure
Dx:IgG, PCR Tx: Interferon
Flaviviridae Hepatitis
Yellow Fever• Liver / GI• Kidneys• Heart
Hepatitis G• Acute• Persistent• Co-infection with
Hepatitis C• Parental: blood
Encephalitis Japanese Complex Russian
spring/summer St. Louis
• Acute• Inflammatory• Vector: mosquito• 4-21 days
incubation
Flavivirus Encephalitis
Flavivirus West Nile Virus
Acute Febrile Hemorrhagic Vector: mosquito 3-14 days
incubation Dx: IgM, ELISA Tx: Supportive
Flavivirus: Dengue Fever Tropical Aedes mosquito Disease syndromes
Breakbone fever• Rash• Myalgia
Hemorrhagic fever• Reinfection• Hyperimmune
response
Group V: -ssRNA enveloped, segmented
Bunyvirus Orthomyxovirus Arenavirus
ARENAVIRIDAE Arenosus = sand (ribosomes) Enveloped Helical Segmented linear ss- RNA Rodent reservoir Human Disease
Hemorrhagic fever• Old world
• Lassa• Sabia• Junin
Lymphocytic choriomenigitis (LCM)
• New world arenavirus
Arenavirus Hepatitis D
Delta Agent Defective Incomplete ss RNA
• Viroid• Co-infection with HepB• Satellite virus
Enveloped Body fluid spread
BUNYAVIRIDAE Named after location
of first viral isolation Spiked, enveloped Helical Circular ss-RNA Human Disease
Arborvirus• Encephalitis• Respiratory• Hemorrhagic Fever
Rodent• Hanta Virus
Bunyavirus Hanta virus
Adult Respiratory Disease
1-3 weeks incubation Transmission: deer
mice Symptoms
• SOB• N/V• pain
Tx: supportive Prevention: rodent
control, disinfect
ORTHOMYXOVIRIDAE Myxo = mucus Spiked envelope
HA• hemaggluttinin• attach• Antigen number
NA• neuraminidase• through mucus• antigen number
Helical capsid 8 Segmented linear ss-
RNA Human Diseases
Influenza A Influenza B
-ssRNA
Orthomyxovirus Influenza
Range of symptoms from mild to severe
Droplet • Direct• Indirect
1-3 days incubation Reservoir: Humans Treatments
• Vaccination• Drugs
Complications• Recombinant due to
segmented RNA• Secondary bacterial
infections• Viral super infection with
Adenovirus
Influenza Treatments Inhibit Neuraminidase
Relenza (IN)Tamiflu (PO)
Antigenic drift: HA/NA mutationsAntigenic shift: genetic reassortment
Influenza Pandemics
Group V: -ssRNA enveloped, nonsegmented Paramyxovirus
Morbillivirus Parainfluenza Rubella RSV Nipahavirus
Rhabdovirus Filovirus
PARAMYXOVIRIDAE Similar to
Orthomyxoviruses Spiked Envelope
HA NA Fusion (F protein)
Helical Segmented linear ss –
RNA Human Diseases
Respiratory Epithelial
Paramyxovirus : Respiratory Parainfluenza
4 types (HPIV) Pediatric infection Symptoms
• Fever• Coryza• Barking cough
(Croup)• Airway obstruction
Droplet Tx: supportive
Paramyxovirus :Respiratory Respiratory
Syncytial Virus (RSV) Infants Pneumonia
• lower airways• Alveoli damaged
Symptoms• Cold like• Fever• Coryza• Cough• Wheeze• Dsypnea
Droplet Tx: supportive
Paramyxovirus: Epithelial Mumps
Glandular (Parotiditis) Droplet transmission 21 day incubation Inflammation Complications
• Encephalitis• Orchitis• Nephritis• Pancreatitis• Arthritis
IgM Tx: symptomatic Prevention: MMR
Rubulavirus
Mumps Pathogenesis
Paramyxovirus: Epithelial Measles (Rubeola)
Epithelial mucosal linings
• Skin -> rash• Respiratory• GI
Complications• Panencephalitis• Conjunctivitis
Droplet transmission 10-12 days incubation Desquamation Highly infectious Tx: symptomatic Prevention: MMR
Morbillivirus
RHABDOVIRIDAE Rhabdo = rod like Spiked, enveloped
Hemagglutin Helical -ssRNA Human Disease
Vesicular Stomatitis Rabies
Rhabdovirus Lyssa virus
Rabies• Encephalitis• Direct• 3-8 weeks incubation• Replication
• Local• CNS• Salivary
• Reservoir• Bats• K-9 / coyotes / foxes• Racoons• Skunks
• Clinical• Furious• Dumb
Tx: IgGPrevention: vaccination
FILOVIRIDAE Filo = filamentous Spiked, enveloped Helical Linear ss – RNA Pleomorphic shape
Filament, branched, U-shape, Circular
Gp epithelial receptors
Human Disease Acute Hemorrhagic
fevers• Marburg Virus• Ebola Virus
Marburg Fruit bat/green monkey Africa (Germany isolated Body fluid spread 3-9 day incubation Course
Rash Gi inflammation Liver failure Pancreatitis Hemorrhageshock MODSDeath
Ebola virus Africa Direct contact Acute hemorrhagic
fever 4-16 day incubation Symptoms
Fever V/D Rash Hemorrhage from all
open body cavities Death due to shock from
fluid and blood loss
RETROVIRIDAE Retro = reverse RNA dependent DNA polymerase (RT) Spiked envelope polyhedral 2 linear +ssRNA (diploid virus) Enzymes
Reverse transcriptase Protease Integrase
Human Diseases Deltaretrovirus HTLV: leukemia Lentivirus HIV: AIDS
Retroviridae Human T-Lymphocytic
Virus (HTLV-1) Adult T cell Leukemia Aggressive Tumor Latent Infiltrates
• Skin• brain
Transmission• Horizontal
• Blood• Sexual Intercourse
• Vertical• Breast milk
Retroviridae Human T-Lymphocytic
Virus (HTLV-2) B-Lymphocytes Hairy cell leukemia
• Slow growing• Middle aged men• Type of CLL
Signs• Bruising/bleeding• Swollen LN• Fatigue• Fevers
Human Immunodeficiency Virus
Ecological Groups Arboviruses
Arthropod borne viruses
Transmitted by• Insects• Mites• Ticks• Lice
Viral Families• Togavirus• Bunyaviridae• Rhabdovirus (some)• Arenavirus (some)• Reovirus (some)
Oncoviruses Cancer causing DNA related Viral Families
• Papovirus• Adenovirus• Parvovirus• Herpesvirus• Retrovirus
Zoonoses Disease that humans can acquire from
animals Viral examples
Marburg (monkeys) Pox (cow pox, pseudo-cowpox, monkey pox)
Rabies (warm blooded mammals)
Influenza A Lassa (rodents, bats) Hanta virus: pulmonary (rodents)
Viral Vaccines Live / Attenuated
Measles Mumps Rubella Polio (oral) Yellow Fever VZV
Killed / Viral Protein Hepatitis A Hepatitis B Rabies Polio (Salk)
Antiviral Chemotherapy Inhibits Viral DNA-dependent DNA polymerase
Herpes Inhibits DNA replication and transcription
Herpes Interferes with penetration or viral uncoating
Influenza A Inhibits translation of late mRNA
Smallpox Inhibits reverse transcriptase
Aids Inhibits Protein synthesis
Genital Warts
Questions?