1. FAMILY CALICIVIRIDAE

2. Viral Morphology Non-enveloped: 27-40 nm (+) ss RNA Some cultivable and some no Replication: cytoplasm

3. Structure

4. Noroviruses Taxonomy Caliciviridae: Genus: 1.Norovirus : Norwalk virus (1968, Norwalk OH) 2.Sapovirus : Sapporo-Like Virus 3.Lagovirus : Rabbit Hemorrhagic Disease Virus 4.Vesivirus : Vesicular Exanthem Virus 1 & 2 : human and non cultivable 3 & 4 : animal and cultivable

5. Path of Infection Wagner et al. Basic Virology. www.netlibrary.com

6. Norovirus : Norwalk virus Incubation period: 24-48 hours gastroenteritis “winter vomiting disease” Mistakenly termed- “stomach flu” Highly contagious: fewer than 100 virus particles can cause infection

7. Epidemiology and Incidence The most important cause of Epidemic Viral gastroenteritis in Adult(40-50%) Found Worldwide. 267,000,000 annual cases 612,000 hospitalizations 3,000 deaths

8. Prevention and Control Vaccine not likely. No current antiviral drugs Prevent by : 1.hand-washing 2. good hygiene 3.preparation of food

9. Asteroviruses 28-30nm +Ss-RNA Mamastoviruses ( all human viruses) Diarrheal in infant, children, elderly person and immunocompromised persons. Transmission: fecal-oral, food,water and person to person