Understanding Hepatitis -- the Basics
What Causes Hepatitis? continued...
The hepatitis A virus commonly spreads through improper handling of food, contact with household members, sharing toys at daycare centers, and eating raw shellfish taken from polluted waters. Simply eating out in a restaurant can put you at risk of Hepatitis A.
The following people have a higher risk of getting hepatitis A:
- People who travel to developing countries
- Men who have sex with men
- People who have oral-to-anal sex
- Intravenous drug users
- People who have contact with sewage
- Employees and children (particularly those in diapers) at daycare centers
- Employees and patients in institutions for the mentally disabled
- People who work with primates, such as apes and monkeys
- People who live in crowded conditions with poor sanitation
Hepatitis B can spread through sex (it is 100 times easier to spread through sex than HIV), blood transfusions (mostly before 1975), and needle sharing by intravenous drug users. The virus can pass from mother to child at birth or soon afterward; the virus can also pass between adults and children to infect whole families. Other people at risk include those with kidney failure who are undergoing hemodialysis -- a procedure that helps filter blood -- or those receiving a transplanted organ infected with the hepatitis B virus.
Most adults with hepatitis B get better, but a small percentage of them can't shake the disease and become carriers. Carriers can transmit the disease to others even when their own symptoms have disappeared. A smaller percentage of adults who cannot fight off the virus will develop chronic hepatitis B. Like carriers, those with chronic hepatitis B are able to pass the virus.
Almost 350 million people worldwide, including 800,000 to 1.4 million people in the United States, are chronic carriers of this virus. Worldwide, about 786,000 people die annually from hepatitis B. Hepatitis B is the most common cause of cirrhosis and liver cancer worldwide.
Hepatitis C is usually spread through contact with blood or contaminated needles, including tattoo needles. 3.2 million people in the US are chronically infected. Although hepatitis C may cause only mild symptoms or none at all, about 5% to 20% of those infected develop cirrhosis within 20 to 30 years. The disease can be passed on through blood transfusions, but screening, which started in 1992, has greatly reduced the number of such cases. As opposed to hepatitis B, hepatitis C is only infrequently spread through sex.
Hepatitis D happens only in people infected with hepatitis B and tends to make that disease more severe. It can be spread from mother to child and through sex. Although less common, hepatitis D is especially dangerous, because it involves two viruses working at once.
Hepatitis E happens mainly in Asia, Mexico, India, and Africa; only a few cases are reported in the United States, mostly in people who have returned from a country where the disease is widespread. Like hepatitis A, this type is usually spread through fecal contamination, and it does not lead to chronic hepatitis. This form is considered slightly more dangerous than hepatitis A. It can cause severe disease and death in pregnant women.