Hepatitis

Hepatitis is a disease characterized by inflammation of the liver, usually producing swelling and, in many cases, permanent damage to liver tissues. A number of different agents can cause hepatitis, including infectious diseases, chemical poisons, drugs and alcohol. Viral hepatitis refers to a set of at least six viruses that are known to cause hepatitis: hepatitis A (HAV), hepatitis B (HBV), hepatitis C (HCV), hepatitis D (HDV), hepatitis E (HEV), and hepatitis G(HGV). Recent scientific evidence also suggests the existence of other, as yet unidentified hepatitis viruses.

The most common types of viral hepatitis are hepatitis A, B, and hepatitis C. Both hepatitis B and C can lead to serious, permanent liver damage, and in many cases, death.

There are two primary types of viral hepatitis, food-borne and blood-borne hepatitis. The former, which is spread through contaminated food and water, does not cause chronic liver disease. By contrast, bloodborne viral hepatitis may lead to long-term, persistent infections and chronic liver disease that has lethal consequences many years after infection.

Food Borne Hepatitis

Hepatitis A
Hepatitis A is usually transmitted by drinking water or eating food that has been contaminated with fecal matter containing the virus. Thus, the risk of contracting hepatitis A generally depends on the hygenic and sanitary conditions in a given area. The Centers for Disease Control estimates that 150,000 people in the United States are infected each year by hepatitis A, a low rate compared to the underdeveloped countries. There are two approved vaccines available in the U.S. for protection against hepatitis A.

As is common with the other forms of viral hepatitis, the infected person may not have any symptoms. When they do occur, symptoms resembling the flu normally appear during the first four weeks of infection. These include fatigue, nausea, vomiting, pain in the liver area, dark urine or light colored stools and fever. Liver function tests are elevated, with many adults developing jaundice. Most people recover from the hepatitis A virus within six months without any serious health problems.

Fecal matter from an infected person has a high concentration of the virus. The virus can survive in fecal matter on a person's hand or other surfaces for three to four hours at normal room temperatures. Eating utensils are a frequent source of infection, as are contaminated shellfish and I.V. drug use. Intimate contact of any kind with an infected person can also transmit the virus.

A very small percentage of people, frequently those having pre-existing liver disorders, risk serious complications from hepatitis A. Federal mortality statistics for 1992 listed hepatitis A as the primary cause of death for 82 people in the United States.

Hepatitis E
Hepatitis E, whose symptoms and methods of transmission resemble hepatitis A, is caused by a virus commonly found in the Indian Ocean region, Africa, and in underdeveloped countries. Testing for hepatitis E is being developed but is not yet available commercially. The symptoms of hepatitis E are like those of hepatitis A, although the period of illness may be as long as several months. Hepatitis E is rarely, if ever, responsible for causes of chronic hepatitis.

Adequate sanitation and good personal hygiene reduces the risk of hepatitis A and E. Water should be boiled prior to its use if any question of safety exists. Similarly, in areas where sanitation is questionable, food should be cooked well and fruits peeled. Those planning to travel to areas where hepatitis A or E is widespread are advised to take immune globulin before leaving.

Blood Borne Hepatitis

Hepatitis B Virus
Hepatitis B virus (HBV), formerly called serum hepatitis, is much more prevalent than HIV ( the virus that causes AIDS). An estimated 1.2 million Americans are currently chronic carriers of HBV, with more than 300 million carriers in the world. Hepatitis B may develop into a chronic disease (lasting more than 6 months) in up to 10% of the newly infected people each year. If left untreated, the risk of developing cirrhosis (scarring of the liver) and liver cancer is greatly increased.

This disease is much more infectious than HIV. It is transmitted through infected blood and other body fluids (seminal fluid, vaginal secretions, breast milk, tears, saliva and open sores). In the U.S., hepatitis B is spread predominantly through sexual contact. Other risk groups include health care workers, prison inmates and personnel, IV drug users, and recipients of blood transfusions prior to 1975. In families, it appears that the virus can be casually spread from adults to children.

The onset of hepatitis B is gradual. As with other forms of hepatitis, most people who get hepatitis B have no recognizable signs or symptoms. But some people do experience flu-like symptoms, such as loss of appetite, nausea and vomiting, fever, weakness, tiredness, as well as mild abdominal pain. Less common symptoms are dark urine and yellowing of the skin and eyes (jaundice). The only way these diseases can be positively identified is through blood tests. However, over 90 to 95 percent of adult patients recover within six months, while 5 to 10 percent develop chronic hepatitis or become carriers. Severe manifestations of chronic HBV infection include development of scarring of the liver (cirrhosis), and liver cancer which usually occurs decades later.

An HBV carrier is someone who has had hepatitis B in their blood for more than six months. A carrier usually has no signs or symptoms of HBV but remains infected with the virus for years or for a lifetime and is capable of passing the disease on to others. Two types of vaccine are available to prevent hepatitis B.

Hepatitis D Virus
Infection with hepatitis D (HDV) occurs only in patients already infected with hepatitis B. Hepatitis D is spread mainly by contaminated needles and blood. I.V. drug users have a high incidence. The simultaneous infection with HBV and HDV produces more severe illness, and higher rates of long term liver failure, than HBV alone. The disease is usually self-limited, and due to its co-dependence on HBV, hepatitis D is effectively prevented via the HBV vaccine.

Hepatitis G
A newly identified strain of hepatitis, hepatitis G is currently under study. The first major study of virus has reported that those infected by means other than blood transfusions did not develop chronic liver disease, although for most the virus remained in their blood for several years. It is not clear at this time how widespread hepatitis G is, what the means of transmission are, or what its precise effects are on infected patients.

Other Hepatitis Viruses
There is accumulating evidence that other hepatitis viruses exist - in part due to the fact that the known viruses (A through G) do not explain all cases of hepatitis that are believed to be caused by viruses. Detailed studies are currently underway. However, the clinical significance and public health impact of other hepatitis viruses remains unknown.

Prospects for treatment
There is no vaccine for hepatitis C at present, and it may be a long time before one becomes available. The great variation in genotypes with hepatitis C, as well as its frequent mutation, makes the development of treatments and vaccines extremely difficult. Liver transplantation may be life-saving in end-stage liver disease, but is costly and involves continuing health care following the procedure. This treatment option is further complicated by a shortage of liver donors. For HCV-positive patients under going transplantation, re- infection is almost universal.

There are a number of drug treatments becoming available for hepatitis C. Infected individuals should consult with their physician to see about the availability and effectiveness of these treatments, as well as the possibility of participating in experimental drug trials.