Hepatitis B and similar diseases

Hepatitis B and similar diseases: The word hepatitis refers to any disease that causes inflammation of the liver. The most common cause of hepatitis is infection of the liver by a virus.
Until the 1940s physicians thought that there was only one type of viral hepatitis. A second virus that produces hepatitis was discovered as a result of an accident. Although similar in symptoms to the previously known hepatitis infection, the new form spread by an entirely different route. Today the two types are called A and B. Increasing ability to detect differences among viruses led researchers to identify perhaps as many as ten different viral liver infections, all of which are called hepatitis. The one known as hepatitis C is very common. Hepatitis D is not a disease-causing virus by itself but makes infections with B worse. For that reason, some physicians prefer to call it "the delta factor" instead of D. Hepatitis E is more like A than it is like the others. Identification of the viruses called hepatitis F, G, H, I, and J is still tentative.

Cause The virus that causes hepatitis B, unlike the one for hepatitis A or E, is transmitted primarily by infected blood or during unprotected sex, although mothers sometimes transmit it to children shortly after birth. (Hepatitis A and E are usually spread by contaminated water or food.)
Hepatitis C is primarily spread by blood products, although it is thought that there is a slight chance of transmission by sexual contact. In the case of hepatitis D, or the delta factor, the infectious agent is more like a viroid, a plant pathogen that consists almost entirely of nucleic acid, than like a virus. The hepatitis D virus needs to use the outside coat from a hepatitis B virus to infect cells, so it is a cofactor of that disease. A person without a hepatitis B infection cannot contract hepatitis D.
Not much is known about how the tentatively identified other forms of hepatitis are transmitted.

Incidence Some estimates are that 1 out of 20 Americans will have hepatitis B at some time in their lives, but more than half of those will not notice it.
Since hepatitis B is not only transmitted by blood products but also sexually, it can infect a population that is more geographically spread out than the small groups that often develop hepatitis A from a single water source. Hepatitis B, for example, was found to be rampant in the male homosexual community during a period in which there was a great deal of promiscuity.
Since 1990, when a blood test for hepatitis C became available, physicians have learned that the C virus causes by far the most common hepatitis, with an estimated 3.5 million people infected in the United States. Although the incidence of hepatitis C is very high among poverty-stricken people tested, the virus shows up in only about 1 in 200 persons among healthy blood donors. Nevertheless, it is estimated that about 35,000 to 180,000 new cases of hepatitis C will be detected each year in the United States, leading to 8,000 to 10,000 deaths.

Symptoms you are likely to notice The earliest symptom of hepatitis for many infected is jaundice, a yellowish cast to the skin or whites of the eyes caused by poor liver function. Other symptoms include those similar to various "flus," such as nausea, loss of appetite, vomitting or diarrhea, and fatigue. Poor liver function can lead to clay-colored stools, dark urine, or pain in the region of the liver. Symptoms for hepatitis B, when they appear, tend to be stronger and longer lasting than the similar symptoms for hepatitis A or E.
Half of all infections with hepatitis B or C cause no symptoms at all. But sometimes infection with the B or C viruses can lead to serious complications later, even when not symptomatic at first.

Symptoms your physician may observe Hepatitis B can be identified by a commercial blood test. About 60% of those chronically infected with hepatitis C have enough inflammation to allow the disease to also be detected by a commercial blood test. Tests for hepatitis C carriers who do not have an inflamed liver are performed only by specialists. A commercial blood test is available for hepatitis D as well.

Treatment options Known exposure to hepatitis B virus may be treated with immune B globulin, although the blood fraction can sometimes provoke severe allergic reactions; hence treatment must be carefully monitored. For all forms of hepatitis bed rest is the main treatment if symptoms are noticeable. If dehydration becomes a problem, a patient may be put into the hospital for intravenous administration of liquids. If the liver is severely inflamed, steroids may be injected.
Since February 26, 1992, treatment of hepatitis C with genetically engineered alfa (alpha) interferon has been approved by the U.S. Food and Drug Administration. It is a long-term treatment, not a cure. Alpha interferon is also helpful in restoring liver function in patients with hepatitis B. Many patients experience flulike symptoms as a result of the treatment and may feel worse than they did before treatment started. For any liver disease alcoholic beverages are harmful, especially if combined with the common pain reliever acetaminophen (common trade name: Tylenol).

Stages and progress Infection with hepatitis B can be mild and fairly short-lived in many cases. As with most viral illnesses, after a time the immune system prevails and all symptoms go away. In other instances the disease symptoms go away, but the virus continues to infect liver cells, a condition called chronic. For hepatitis B the disease becomes chronic in 5 to 10% of all patients.
In some cases the chronic hepatitis has no further effect on the human host but the virus is able to spread to other humans. In other instances chronic hepatitis can lead to the scarring of the liver called cirrhosis. Severe cirrhosis interferes with liver function and can lead to death. Finally, hepatitis B is thought to cause liver cancer in a fairly high percentage of cases.
Sometimes liver function is badly compromised and the disease takes a sharp turn for the worse. Acute hepatitis (from any cause, including chemical poisoning as well as any of the various viral infections) is known as fulminant hepatitis fulminant means that it occurs suddenly and intensely; it may affect the brain, resulting in coma or even death.
Hepatitis B can become fulminant or occur as an acute attack. For a person with both the B and D viruses, the probability of fulmination or cirrhosis is enhanced over the chances with B only.
About 50 to 70% of those who test positive for the hepatitis C virus have no symptoms at all. Nearly everyone becomes chronically infected, however. In many cases symptoms are mild fatigue, nausea, and weight loss. Others develop cirrhosis of the liver or liver failure.

Prevention and risk factors The risk factors for hepatitis B are similar to those for AIDS, with sexual transmission, especially among homosexual men, common, as well as transmission in blood between drug users sharing needles. Hepatitis B is common among homosexual men, reaching perhaps as many as 80% of the population. Shared needles are also a principal means of transmission for hepatitis C.
Blood transfusions are no longer a risk for contracting hepatitis B or C because the blood supply is monitored for both viruses. Infected blood is still believed to be the main cause of hepatitis C, but most new cases result from drug abusers sharing needles and not from transfusions.
Vaccines have been developed for hepatitis B; the one currently used is manufactured by genetic engineering, so it cannot infect the person vaccinated. Once suggested for high-risk individuals only, the vaccine is now part of the standard series of vaccinations for infants.

History During World War II the pattern of a major outbreak of serious hepatitis quickly led to the discovery of another mode for transmission of the disease. A newly developed vaccine intended to protect American troops against yellow fever had to be withdrawn quickly when the vaccine was found to be the cause of the hepatitis outbreak. The vaccine had been made from human blood products. Research into this kind of hepatitis after the war can be counted - along with deliberate exposure to radioactive substances, experimental nontreatment of syphilis, and administration of psychedelic drugs to unsuspecting personnel - as one of the serious abuses of research in the name of science. Children with Down's syndrome and prisoners were deliberately injected with infected blood to determine the cause and progress of the newly discovered form of hepatitis.

Hepatitis C, new and drug-connected Although the existence of hepatitis C has been officially recognized since 1975, and the infection is now very common, there is evidence that hepatitis C did not exist or was at least rare only 50 years ago. Stored blood samples from World War II fail to test positive for the disease. Scientists working with hepatitis B in the 1960s found many puzzling cases of liver disease that seemed to be something different from B, and these are now assumed to be largely hepatitis C. Thus the disease came into being or became widespread in the 1950s. This period coincides with the first wave of intravenous drug use in the United States, and that may be no coincidence.