Foodbourne Illness

Ainsley Stewart

Health and Wellness

Prof. Michael Wagstaff

Hepatitis A

What is the infectious agent (pathogen) that causes this infectious disease?

Hepatitis A virus HAV is an RNA virus classified as a picornavirus.

How is this infectious agent transmitted through food or water?

There are a number of ways that one can get the HAV and there are; person-to-person contact; through exposure to contaminated water, ice, or shellfish harvested from sewage-contaminated water; or from fruits, vegetables, or other foods that are eaten uncooked and that were contaminated during harvesting or subsequent handling. HAV is shed in the feces of infected people. The virus reaches peak levels 1–2 weeks before onset of symptoms and diminishes rapidly after liver dysfunction or symptoms appear, which is concurrent with the appearance of circulating antibodies to HAV. Infants and children, however, may shed virus for up to 6 months after infection.

What is an example of a real life outbreak of this foodborne illness in the United States?

The occurrence of hepatitis A in the United States is heterogeneous because of disease cycles with substantial variation in incidence among states and involvement of numerous behavioral risk factors. In spite of the Advisory Committee on Immunization Practices' (ACIP) 1999 recommendation for routine hepatitis A immunization in states with high rates of disease and the fact that disease rates are at a historic low, outbreaks continue to occur. A total of 256 hepatitis A outbreaks were identified from 1994 through 2004. The mean number of outbreaks was 23 per year median 25. The number of outbreaks in states with traditionally low/intermediate endemic rates of hepatitis A remained relatively constant during the study period. Outbreaks declined significantly in states with previously high rates of disease most of which have implemented hepatitis A vaccination programs.

What are the clinical symptoms, duration of the disease, and...