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Foodborne & Waterborne Disease Viruses

Suphachai Nuanualsuwan DVM, MPVM, PhD. Foodborne & Waterborne Disease Viruses. 1. Introduction. Foodborne and waterborne disease viruses Top 3 foodborne disease outbreak during 1988-1997(10 years) following bacteria and chemical Data from CDC most updated unknown etiology was ~ 64%

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Foodborne & Waterborne Disease Viruses

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  1. Suphachai Nuanualsuwan DVM, MPVM, PhD Foodborne & Waterborne Disease Viruses 1. Introduction

  2. Foodborne and waterborne disease viruses • Top 3 foodborne disease outbreak during 1988-1997(10 years) following bacteria and chemical • Data from CDC most updated • unknown etiology was ~ 64% • passive record Suphachai DVM, MPVM, PhD

  3. Outbreak by etiology 1988-1997 Etiology % Outbreak Bacteria 28 Chemicals 5.6 Parasites 0.7 Viruses 1.9 Known etiology 36.6 Unknown etiology 63.7 Source : CDC 1996 Surveillance for foodborne disease outbreaks-US 1988-1992 MMWR 45(ss-5): 1-71 CDC 2000 Surveillance for foodborne disease outbreaks-US 1993-1997 MMWR 49(ss-1): 1-62

  4. Estimated cases by etiology • Etiology % Cases • Bacteria 13.47 • Parasites 6.58 • Viruses 79.95 • Noroviruses 59.54 • Rotavirus 10.10 • Astrovirus 10.10 • Hepatitis A virus 0.22 Source : Mead, et al 1999. Food related illness and death in the United Stated Emerging Infectious diseases 5(5) 607-625

  5. Foodborne and waterborne viruses • Estimated Top 1 of food-related illness • Higher than bacteria & parasites combined Suphachai DVM, MPVM, PhD

  6. Common properties among FB-WB viruses • inert transmissible particles • fecal-oral route • human specific • non-cytopathic effect • non-enveloped viruses Suphachai DVM, MPVM, PhD

  7. Common properties of FB-WB disease viruses • 1. inert transmissible particles • viruses are not a living organism • diameter of < 30 nanometers (mostly) • icosahedral symmetry • single stranded RNA (+) (mostly) • RNA-dependent RNA polymerase(RdRp) • intracellular parasites Suphachai DVM, MPVM, PhD

  8. What is VIRUS ? A group of infectious agents characterized by their inability to reproduce outside of a living host cell. Viruses may subvert the host cells' normal functions, causing the cell to behave in a manner determined by the virus. Virion: Virus particle – Infectious (native) or noninfectious Suphachai DVM, MPVM, PhD

  9. Icosahedral symmetry Noroviruses Poliovirus type 1

  10. Nonenveloped enteric viruses in human Diameter Nucleic acid (nm) Stranded RNA DNA 25-38 single Astrovirus Parvovirus Calicivirus Coronavirus Picornavirus 70-85 double Reovirus Adenovirus Rotavirus

  11. diameter of < 30 nanometers (mostly) Diameter of Hepatitis A virus ~ 28 nm Diameter of Calicivirus ~ 30 nm Suphachai DVM, MPVM, PhD

  12. Common properties of FB-WB disease viruses • 2. Fecal oral route transmission • virus ingestion -> virus shedding • direct transmission • fecal-oral route • person-to-person route • indirect transmission • food & water • fomite Suphachai DVM, MPVM, PhD

  13. Common properties of FB-WB disease viruses • 3. Human adaptation • all FB-WB disease viruses are human specific except Hepatitis E virus(HEV) and Tick-borne encephalitis virus • associated with sanitation rather than undercooked meat Suphachai DVM, MPVM, PhD

  14. Common properties of FB-WB disease viruses • 4. Difficult to culture in laboratory • human specific • no lab host cells or no cytopathic effect(CPE) renders infectivity test difficult • RT-PCR is a leading diagnostic tool yet cannot differentiate infectious and inactivated viruses Suphachai DVM, MPVM, PhD

  15. Common properties of FB-WB disease viruses • 5. Non-enveloped viruses • all FB-WB disease viruses are non-enveloped • resistant to environmental condition e.g. pH, heating, UV Suphachai DVM, MPVM, PhD

  16. Foodborne and Waterborne Disease Viruses • 1. Noroviruses(NV)formerly Norwalk-like viruses • 2. Rotaviruses • 3. Hepatitis A virus(HAV) • 4. Hepatitis E virus(HEV) • 5. Other viruses • Astrovirus • Parvovirus • Tick-borne encephalitis virus • Enteroviruses • Adenovirus • Coronavirus Suphachai DVM, MPVM, PhD

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