Foodborne & Waterborne 23/04/60 Foodborne & Waterborne Disease Viruses 2. Norovirus & Rotavirus Suphachai Nuanualsuwan DVM, MPVM, PhD

Noroviruses 1. Virus particle formerly Norwalk-like viruses since first outbreak in Norwalk, Ohio, U.S.A. gastroenteritis virus one of 2 human Calicivirus genera small round, structured viruses (SRSV) ~ 30-38 nm single structural protein ssRNA(+) of 7,500 bases Suphachai DVM, MPVM, PhD

Electronmicrographs and model of Caliciviruses Norovirus Suphachai DVM, MPVM, PhD

Noroviruses 2. Disease gastroenteritis mild and self-limiting “winter vomiting disease” projectile vomiting incubation period is dose-dependent incubation period & illness duration 24-48 hr. Suphachai DVM, MPVM, PhD

Noroviruses 3. Transmission and Control major virus shedding in 1.vomitus and 2.stool infection primary infection : food or water secondary infection : infected patients aerosol droplet can shed virus on the fomite Suphachai DVM, MPVM, PhD

Suphachai DVM, MPVM, PhD

Noroviruses 4. Epidemiology person-to-person by fecal-oral is main route through food handlers institutional outbreak : the poor sanitation food & water contaminated with virus particles shellfish e.g. oyster recreational water no age specific Suphachai DVM, MPVM, PhD

Noroviruses 5. Stability in case of prevention broke need to inactivate virus in food or water nature of FB-WB disease viruses are resistant to the environment inactivation (data usually from epidemics) drying on the fomite surface pH heating Ultraviolet(UV) and chlorine Suphachai DVM, MPVM, PhD

Noroviruses 6. Food and Risk factors A safe food handler Suphachai DVM, MPVM, PhD

Shellfish bivalve mollusk found in shallow coastal, estuarine water feeding by filtration accumulate virus particles eating raw or undercooked shellfish? oyster mussel clam cockle Suphachai DVM, MPVM, PhD

Shellfish thoroughly cooking to inactivate viruses Suphachai DVM, MPVM, PhD

Relaying and Depuration not standard for viruses Shellfish Relaying and Depuration not standard for viruses Suphachai DVM, MPVM, PhD

Personal sanitation of food handlers A safe food handler Suphachai DVM, MPVM, PhD

Noroviruses formerly Norwalk-like viruses Caliciviridae family incubation and illness ~ 24-48 Hr. gastroenteritis virus distinctive symptom: vomiting virus shedding in vomitus and stool transmission: fecal-oral route diagnosis: epidemiology, symptom, RT-PCR

Rotavirus infection Suphachai DVM, MPVM, PhD

double coat protein & icosahedral symmetry diameter of 70-80 nm Rotavirus 1. Virus particles Reoviridae family double coat protein & icosahedral symmetry diameter of 70-80 nm 11 dsRNAs -> re-assortment diverse serotypes Group A rotaviruses (7 serotypes) mostly found in children < 5 years Suphachai DVM, MPVM, PhD

food and water contaminated with viruses pre-harvest and post-harvest Rotavirus 2. Implicated food Shellfish food and water contaminated with viruses pre-harvest and post-harvest Suphachai DVM, MPVM, PhD

gastroenteritis -> acute diarrhea Rotavirus 3. Disease gastroenteritis -> acute diarrhea vomiting, fever, and respiratory illness water and electrolyte loss malnutrition as aggravating factor serious in children, mild for adult incubation period ~ 1-3 days illness duration ~ 4-6 days Suphachai DVM, MPVM, PhD

shedding virus ~ 8 days after disease onset institutional outbreak Rotavirus 4. Epidemiology shedding virus ~ 8 days after disease onset institutional outbreak very low infective dose children < 5 years ~ 6-24 % diverse serotypes -> re-infection short-term IgG(<2 wk) -> re-infection non-seasonal associated with sanitation Suphachai DVM, MPVM, PhD

Rotavirus 5. Transmission/Control food & water fertilizer, sewage water treatment, supplies, distribution fomites and environmental surface relative humidity, porous surface sediment hands and fingers 63 % of transmission polyvalent vaccine

fecal-oral route <- sanitation gastroenteritis, vomiting, fever Rotavirus fecal-oral route <- sanitation gastroenteritis, vomiting, fever children < 5 years got serious illness short-term immunity 2-4 weeks Suphachai DVM, MPVM, PhD

23/04/60