It is caused by a virus. The virus is found by doing a blood test. Some cases are quite mild, especially in children. Adults are usually sicker. Symptoms begin 2-6 weeks after a perons is exposed to the virus.
Some persons have no symptoms at all.
A sick person is contagious to others from two weeks before illness, to two weeks after. Drinking water with infected stool in it. Contact with the sick person's stool, such as after changing a diaper or when having sex. Eating raw seafood, such as oysters, from contaminated water. Persons sick with hepatitis A should rest and follow their doctor's advice.