Clinical Significance:
Hepatitis A virus accounts 20-25% of hepatitis in worldwide. The biochemical changes seen in hepatitis A virus infection are: Serum bilirubin levels usually 5-10 times normal, Serum AST and ALT increased to hundreds for 1 – 3 weeks. It never leads to a chronic disease. It occurs sporadically and once infected lifelong immunity is assumed. It rarely develops into fulminant hepatitis.
Characteristics:
Positive single-stranded RNA, no envelope, 27-30 nm diameter, Picornaviridae, Hepatovirus; can be cultured in cell culture
Mode of transmission:
- Person-to-person by faecal-oral route.
- Ingestion of contaminated food (i.e., shell fish) and water.
- HAV is excreted in a highly concentrated form in the feces for a short period of time, reaches peak level the week or two before onset of symptoms.
Incubation Period:
From 10-50 days, depending on dose; average 28-30 days.
Culture:
Virus cannot be cultured in vitro from clinical material.
Serology:
Anti- HAV lgM is earliest to be detected by ELISA along with the HAV total antibodies which includes the detection of all the antibodies. lgG appears in 1- 4 weeks after acute illness.
