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Foodborne & Waterborne Disease Viruses

Suphachai Nuanualsuwan DVM, MPVM, PhD. Foodborne & Waterborne Disease Viruses. 3. Hepatitis viruses. Hepatitis-causing viruses. Suphachai DVM, MPVM, PhD. Type Nucleic acid Alias Transmission HAV (+)ssRNA Infectious hepatitis Fecal-oral

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Foodborne & Waterborne Disease Viruses

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  1. Suphachai Nuanualsuwan DVM, MPVM, PhD Foodborne & Waterborne Disease Viruses 3. Hepatitis viruses

  2. Hepatitis-causing viruses Suphachai DVM, MPVM, PhD

  3. Type Nucleic acid Alias Transmission HAV (+)ssRNA Infectious hepatitis Fecal-oral HBV dsRNA Serum hepatitis Parental HCV (+)ssRNA Non-A Non-B Parental HDV (-)ssRNA Hepatitis delta Parental HEV (+)ssRNA Non-A Non-B Fecal-oral Hepatitis-causing viruses Suphachai DVM, MPVM, PhD

  4. Hepatitis A virus(HAV) • 1. Virus particle • hepatovirus, picornaviridae • single serotype • 28 nm • (+)ssRNA Suphachai DVM, MPVM, PhD

  5. Hepatitis A virus(HAV) • 2. Implicated food • shellfish • water • strawberry, lettuce Suphachai DVM, MPVM, PhD

  6. Hepatitis A virus(HAV) • 3. Disease pattern • asymptomatic : kid < 5 yr. • acute hepatitis : adult > 14 yr. • mild gastrointestinal illness • incubation period ~ 28 days(4 weeks) virus from GI -> liver -> immune response • liver inflammation(hepatitis) -> jaundice -> liver enzyme(ALT) increase Suphachai DVM, MPVM, PhD

  7. Hepatitis virus migrating to liver intestine

  8. Hepatitis virus shedding to intestine Suphachai DVM, MPVM, PhD

  9. Hepatitis A virus(HAV) • 3. Disease pattern Suphachai DVM, MPVM, PhD

  10. Hepatitis A virus(HAV) • 3. Disease pattern • HAV shedding in stool before onset of illness • Immunoglobulin M rises as ALT enzyme rises • IgM falls while IgG rises • IgM represents recent infection • IgG represents previous infection(permanent) • HAV shedding ~ 2 weeks after onset of illness

  11. Hepatitis A virus(HAV) 3. Disease pattern Suphachai DVM, MPVM, PhD

  12. Hepatitis A virus(HAV) • 4. Transmission/Control • fecal-oral • indirect transmission associated with sanitation • food(shellfish) and water • fomite • secondary infection : household • food handlers Suphachai DVM, MPVM, PhD

  13. Discharge untreated sewage straight into the sea

  14. Hepatitis A virus(HAV) • 5. Epidemiology • Worldwide epidemic

  15. Hepatitis A virus(HAV) • 5. Epidemiology • > 90% got infected < 6 years • children are carrier & asymptomatic • Shanghai China outbreak associated with raw sewage contaminated shellfish in the coastal water -> 300,000 cases over months • homosexual, drug users • sanitation, institutional • visit endemic area should get vaccinated

  16. Sewage discharge Beach Estuarine Seashore Suphachai DVM, MPVM, PhD

  17. Hepatitis A virus(HAV) • Foodborne and waterborne disease virus • shellfish and sanitation • children < 5 yr are carrier and asymptomatic • incubation period ~ 48 days(long) • virus shedding in stool before onset of illness Suphachai DVM, MPVM, PhD

  18. Hepatitis E virus(HEV) • 1. Virus particle • enterically Non-A Non-B(ENANB) hepatitis virus • enterically transmitted Non-A Non-B(ET-NANB) • similar to Calicivirus • diameter 32 nm • (+)ssRNA 7,200 bases Suphachai DVM, MPVM, PhD

  19. Hepatitis E virus(HEV) • 2. Implicated food • mostly drinking water Suphachai DVM, MPVM, PhD

  20. Hepatitis E virus(HEV) • 3. Disease pattern • liver inflammation -> icterus, Hepatomegaly • cannot distinguish from other viral Hepatitis • GI illness: diarrhea, nausea, vomiting + headache, fever • incubation period ~ 40 days (longer than that of HAV) • illness duration ~ 4 weeks • illness of middle aged adults (14-40 yr.) Suphachai DVM, MPVM, PhD

  21. Clinical illness ALT IgG anti-HEV IgM anti-HEV Virus in stool Titer Week after exposure Hepatitis E virus(HEV) 3. Disease Pattern Suphachai DVM, MPVM, PhD

  22. Hepatitis E virus(HEV) • 3. Disease pattern • HAV shedding in stool before onset of illness • IgM rises as ALT rises • IgG rises just soon after IgM • IgM represents recent infection • IgG represents previous infection last 2-14 yr. • HAV shedding ~ 2 weeks after onset of illness

  23. Hepatitis E virus(HEV) • 4. Transmission/ Control • Fecal-oral route • water supplies • sanitation Suphachai DVM, MPVM, PhD

  24. Hepatitis E virus(HEV) • 5. Epidemiology • mortality rate 0.1-1.0% • mortality rate up to 20% in pregnant • swine HEV and human HEV are closely related • endemic in southeast Asia(SEA), middle Asia, middle east, northern Africa, and Mexico Suphachai DVM, MPVM, PhD

  25. Phylogenetic relationships between HEV isolates

  26. Geographic distribution of Hepatitis E

  27. Hepatitis E virus(HEV) • fecal-oral route • longer incubation period than that of HAV • illness of adult with hepatomegaly • serious in pregnant women • temporary immunity Suphachai DVM, MPVM, PhD

  28. Foodborne and Waterborne Disease Viruses • Noroviruses is most prevalent • Rotaviruses in kid & HAV, HEV in adult • Fecal oral route • Food: shellfish & Water: sanitation • preventing virus transmission • Preventing contamination • Inactivation e.g. heat, chlorine, UV Suphachai DVM, MPVM, PhD

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