The liver is located in the right upper abdomen and is protected by the rib cage. It can actually sustain a great deal of damage and continue to work by compensating for lost cells.
Hepatitis is an inflammation of the liver. It can be caused by drug and alcohol abuse or by viral infection. Chronic inflammation of the liver can lead to cirrhosis or liver disease.
Cirrhosis is a scarring of the liver in which the architecture of the organ is distorted; the scarring results from the liver's attempt to heal itself. University's Everson equates the process to a storm blowing through a house and knocking down several walls: When the walls are re-erected, they're put up crooked and the house doesn't function as well. Repeated injuries from wave after wave of alcohol or viral infection can eventually affect the structure to the point that the house is destroyed.
Without a functioning liver, death is certain.
Since scientists identified hepatitis C five years ago, they have gone on to find hepatitis D and E. They suspect a hepatitis F, but it has not yet been identified. Hepatitis D can exist only in concert with hepatitis B; it has a high mortality rate from cirrhosis and liver cancer but can be treated in the same way as hepatitis B. Hepatitis E, which is rare in the U.S. and primarily affects people in developing countries, is similar to hepatitis A in transmission; it has a 10 percent mortality rate in pregnant women but otherwise is not considered fatal.
It is hepatitis C that raises the greatest alarm. It can remain in the body without becoming active. Or it can be active and then, mysteriously, become inactive. When active--a diagnosis made by noting an increase in enzymes produced by the liver--the virus causes repeated inflammations of the liver.
Most known hepatitis C infections, 38 percent, occur from drug abuse, according to CDC statistics. Other known methods of transmission are categorized as: sexual/ household (inapparent inoculations), 13 percent; transfusions, 4 percent; and occupational (mostly medical personnel), 2 percent. That leaves about 40 percent unknown.
Blood screening has lowered the risk of transfusion infections to one-tenth of 1 percent. But a new worry is the widespread use of amateur tattooing as a gang symbol or rite of passage in some cultures.
The current thought on hepatitis C is that, compared to AIDS, it is not easily transmitted through sexual contact. The risk is "very low" for people in stable, monogamous relationships, says Everson. Adding multiple sexual partners--either heterosexual or homosexual--increases the risk.
When one person in a couple is infected, a bigger concern is "inapparent inoculations" through the use of a partner's razor or toothbrush, Everson says. But again, he adds, there has not been enough research to prove or disprove the degree of risk.
In her report on "The Detection, Transmission and Outcome of Hepatitis C Virus Infection," Dr. Miriam Alter, the CDC's top hepatitis expert, notes that no vaccine for the virus is expected in the foreseeable future. Hepatitis C mutates inside the body, she writes, making it difficult, if not impossible, to develop a vaccine to prevent infection.
"Our understanding of the risks of transmission...is limited by inadequate studies, the need for more sensitive tests for the detection of infection and our inability to quantitatively measure infectivity.
"In the absence of a vaccine, the prevention of [hepatitis C] infection will depend on a better understanding of the host and environmental factors that facilitate the transmission of this viral infection."
end of part 1