Hepatitis A is most widespread in parts of the world where standards of sanitation and food hygiene are generally poor, such as parts of Africa, the Indian subcontinent, the Far East, the Middle East, and Central and South America.
The hepatitis A virus, which causes the infection, usually is spread when a person ingests even tiny amounts of contaminated fecal matter. The hepatitis A virus infects liver cells and causes inflammation. The inflammation can impair liver function and cause other signs and symptoms of hepatitis A.
Hepatitis A virus can be transmitted several ways, such as:
1) Eating food handled by someone with the virus who doesn't thoroughly wash his or her hands after using the toilet
2) Drinking contaminated water
3) Eating raw shellfish from water polluted with sewage
4) Being in close contact with a person who's infected — even if that person has no signs or symptoms
5) Having sex with someone who has the virus
Someone with hepatitis A is most infectious from around two weeks before their symptoms appear until about a week after the symptoms first develop.