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Foodborne & Waterborne Disease Viruses

Suphachai Nuanualsuw

anDVM, MPVM,

PhD

1. Introduction

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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

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Etiology % Outbreak

Bacteria 28

Chemicals 5.6

Parasites 0.7

Viruses 1.9

Known etiology 36.6

Unknown etiology 63.7

Outbreak by etiology 1988-1997

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

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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

Estimated cases by etiology

Source : Mead, et al 1999. Food related illness and death in the United Stated Emerging

Infectious diseases 5(5) 607-625

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Foodborne and waterborne viruses

• Estimated Top 1 of food-related illness

• Higher than bacteria & parasites

combined

Suphachai DVM, MPVM, PhD

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Common properties among FB-WB viruses

• inert transmissible particles

• fecal-oral route

• human specific

• non-cytopathic effect

• non-enveloped viruses

Suphachai DVM, MPVM, PhD

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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

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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

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Icosahedral symmetry

Noroviruses Poliovirus type 1

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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

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Diameter of Hepatitis A virus ~ 28 nmDiameter of Calicivirus ~ 30 nm

diameter of < 30 nanometers (mostly)

Suphachai DVM, MPVM, PhD

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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

• fomiteSuphachai DVM, MPVM, PhD

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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 meatSuphachai DVM, MPVM, PhD

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- Common properties of FB WB disease viru

ses

4. Difficult to culture in laboratory

• hhh hh hhhhhhhh

• 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 virusesSuphachai DVM, MPVM, PhD

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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

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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

• CoronavirusSuphachai DVM, MPVM, PhD

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