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Classification of RNA Viruses in Animals: A Detailed Overview

Explore the taxonomy, order, and classification of RNA viruses infecting animals. Learn about families like Reoviridae, Astroviridae, and Caliciviridae, their impact on human health, transmission methods, common diseases they cause, diagnosis, prevention strategies, and more.

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Classification of RNA Viruses in Animals: A Detailed Overview

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  1. RNA Viruses of Animals

  2. Viral Classification • Taxonomy • Order (-viridae) • Family (-viridae) • Subfamily (-virinae) • Genus (-virus) • Species • Group • III (ds) • IV (+ss) • V (-ss)

  3. RNA Virions • Cytoplasm: • Replication • Biosynthesis • Helical capsid • Most enveloped with spikes • NA • Double sense • Single sense (+ / -) • 2 single sense (+)

  4. Viral Entry into Cells

  5. Group III: dsRNA Reoviridae

  6. REOVIRIDAE • REO=Respiratory Enteric Orphan Virus • Non-enveloped • Icosahedral • RNA ds • Segmented • Human Diseases • Rotavirus • Coltivirus

  7. Rotavirus • World wide infection • Fecal-oral spread • Incubation: 1-3 days • Diarrhea • Children • Diagnosis • ELISA • Latex Agglutination • Prevention • Hygiene • Water sanitation

  8. Coltivirus • Colorado Tick Fever • Disease • Acute • Myalgia • Photophobia • Rash • Hemorrhage • Tick vector • Rodent reservoir

  9. RNA ss (+); (-); & retro-

  10. Group IV: +ssRNA nonenveloped • Picornavirus • Rhinovirus • Enterovirus • Hepatovirus • Calicivirus • Astrovirus • Hepevirus

  11. Hepevirus (formerly calcivirus) • +ss RNA • nonenveloped • Icosahedral • Fecal-oral • Domestic pig reservoir • Developing countries/sanitation • Hepatitis E (enteric hepatitis)

  12. ASTROVIRIDAE • Astro = Star • Nonenveloped • +ssRNA • 7 Human Serotypes • Diarrhea • Treatment • Supportive

  13. CALICIVIRIDAE • Calicus • Cup shaped • Indentations • Non-enveloped • Icosahedral • Linear ss + RNA • Human Diseases • Norwalk Virus (Norovirus)

  14. Norwalk Virus Summer diarrhea Epidemic Gastroenteritis V/D Institutions ID virus in stool 90% of viral diarrheas Calicivirus

  15. PICORNAVIRIDAE • Pico = small • Nonenveloped • Icosahedral • RNA + ss • Human Diseases • Enterovirus • Polio • Coxsackie A , B • ECHO • Rhinovirus • Hepatovirus

  16. Rhinovirus • Common cold virus: 50% • Transmission: inhalation • Incubation: 1-3 days • Symptoms • Sore throat • Mucopurulent nasal discharge • Complications • predispose to secondary bacterial infections

  17. 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

  18. Enterovirus • Disease Groups • Poliovirus • Coxsackie A, B • Echovirus • Fecal-oral • Cytolytic • GI mucosa • Lymphatic tissue

  19. Echovirus • ECHO= • Enteric • Cytopathic • Human Orphan • Fecal-oral route • Disease • Meningitis • Paralysis • URTI • Myocarditis • Fever • Rashes • Orchitis

  20. 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

  21. 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)

  22. Poliovirus Bulbar Poliomyelitis Post Polio syndrome

  23. Togavirus Flavivirus Coronavirus Group IV:+ssRNA enveloped

  24. CORONAVIRIDAE Corona = crown Enveloped Helical Linear RNA + ss Respiratory droplet Human Diseases Common cold (20%) SARS

  25. 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

  26. TOGAVIRIDAE • Toga = coat • Spiked envelope • Icosahedral • Linear ss+RNA • ~Arthropod vector • Human diseases • Encephalitis • (VEE, WEE, EEE) • Rubella

  27. Encephalitis: VEE, WEE, EEE all Rodent: VEE

  28. 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: MMR Rubivirus

  29. FLAVIVIRIDAE • Flavus = yellow • Enveloped • Helical • Linear RNA ss + • Human Diseases • Hepatitis • Encephalitis • Hemorrhagic Fever

  30. 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

  31. 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 Flaviviridae

  32. Flavivirus Encephalitis

  33. Flavivirus • West Nile Virus • Acute • Febrile • Hemorrhagic • Vector: mosquito • 3-14 days incubation • Dx: IgM, ELISA • Tx: Supportive

  34. Flavivirus: Dengue Fever • Tropical • Aedes mosquito • Disease syndromes • Breakbone fever • Rash • Myalgia • Hemorrhagic fever • Reinfection • Hyperimmune response

  35. Bunyvirus Orthomyxovirus Arenavirus Group V: -ssRNA enveloped, segmented

  36. 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

  37. Arenavirus • Hepatitis D • Delta Agent • Defective • Incomplete ss RNA • Viroid • Co-infection with HepB • Satellite virus • Enveloped • Body fluid spread

  38. BUNYAVIRIDAE • Named after location of first viral isolation • Spiked, enveloped • Helical • Circular ss-RNA • Human Disease • Arborvirus • Encephalitis • Respiratory • Hemorrhagic Fever • Rodent • Hanta Virus

  39. Bunyavirus • Hanta virus • Adult Respiratory Disease • 1-3 weeks incubation • Transmission: deer mice • Symptoms • SOB • N/V • pain • Tx: supportive • Prevention: rodent control, disinfect

  40. 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

  41. -ssRNA

  42. 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)

  43. Antigenic drift: HA/NA mutations Antigenic shift: genetic reassortment

  44. Influenza Pandemics

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