HA is transmitted via the fecal-oral route, which can occur from direct person-to-person contact, from contamination of the environment or objects, or through contaminated food or water. Transmission through infected blood or blood products has also been reported. Symptoms appear after an incubation period of 15 to 50 days (average 28 days). Cases are typically infectious two weeks before the onset of symptoms and remain infectious until a week after the onset of jaundice. The virus may remain infectious in the environment for several weeks. Viral shedding can be greatly prolonged in immunocompromised individuals.
Persons at increased risk of HA infection include:
- Travellers to HA endemic countries. Studies estimate that 44% to 55% of reported HA cases are linked to travel. Low-budget travellers, volunteer humanitarian workers, and Canadian-born children of new Canadians returning to their country of origin to visit friends and relatives, may be at increased risk.
- Household or close contacts of an acute HA case.
- Residents of certain institutions, such as correctional facilities and those for developmentally challenged individuals.
- Men who have sex with men (MSM).
- Illicit drug users. Increased risk is associated with low hygiene standards, contaminated drugs, and sharing of materials for oral or nasal use of drugs.
- Household or close contacts of children adopted from HA endemic countries.
- Residents in some Aboriginal communities. Higher risk may be attributed to inadequate water supplies and high housing density.
- Hemophiliacs who use plasma-derived blood products.
DIN: 021877078 or 02231056
Source : Public Health Agency of Canada