VIRAL INFECTIONS OF THE GASTROINTESTINAL TRACT (Micro made easy pp 218)

Viruses that cause gastroenteritis (diarrhoea) are acquired via the faecal-oral route. Infants & young children are susceptible. Symptoms include: diarrhoea, nausea, vomiting, abdominal discomfort (typical symptoms). Symptoms occur within 1-2 days of infection, and last about 4-7 days. The reason for death among children is LOSS OF FLUIDS from diarrhoea. Two main viruses implicated in gastroenteritis are rotavirus & caliciviruses & Norwalk agent.

Rotavirus: The most common viral cause for acute gastroenteritis. Up to 1 million deaths p.a. Group A is the most common, Group B found in China. Viral particles found in faeces, incubation period 24hrs. Diagnosis is by EM, ELISA, latex agglutination test for viral antigens. Oral rotavirus vaccines currently being developed.

Norwalk agent: associated with contaminated shellfish + H2O. It’s a non-enveloped SRSV.

Calicivirus: similar to rotavirus. “winter vomiting disease”.

Adenovirus: > 40 serotypes, type 40/41 cause enteric disease. Symptoms last for 8-12 days (compared to usual time of 4-7 days), diagnosis is by ELISA/latex agglutination.

Coronavirus: cause respiratory infections in man, enteric infections in pigs. Diarrhoea in man as well?

Hepatitis: refer to Liver infections lecture.

Category: Microbiology Notes