Hepatitis A

The hepatitis A virus infects at least 180,000 Americans every year and causes symptoms in about 134,000 of them. Almost 30% are children under age 15. Hepatitis A, formerly called infectious hepatitis, is always acute and never becomes chronic. The virus is excreted in feces and transmitted by contaminated food and water. Eating shellfish taken from sewage-contaminated water is a common means of contracting hepatitis A. It can also be acquired by close contact with individuals infected with the virus. It is estimated that 11 - 16% of reported cases occur among children or employees in daycare centers or among their contacts. The hepatitis A virus does not directly kill liver cells, and experts do not yet know how the virus actually injures the liver.

A fly may act as a mechanical vector of diseases such as Hepatitis A, which means the fly carries the infective organism on its feet or mouth parts and contaminates food or water which a person then consumes. A biological vector actually develops an infective organism in its body and passes it along to its host, usually through its saliva. A fly can be a biological vector, as in the transmission of leishmaniasis by the sandfly.

Vaccines for Hepatitis A

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Experts now recommend vaccinations for children and adolescents in high-risk states and communities. Indeed, a 2001 study showed that widespread vaccination of children in one county in California led to dramatic decreases in the number of outbreaks among all adults in the community at large. Others who should be vaccinated against hepatitis A include travelers to developing countries, people living in communities where outbreaks occur, people with blood-clotting disorders, sexually active homosexual men, and health care workers exposed to the virus. People with chronic liver disease, including those with hepatitis C, should also be vaccinated, particularly if they have not been exposed to hepatitis A, since the infection can cause liver failure in these patients.