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Biology 103
2002 First Paper
On Serendip

The Letter B

Catherine Rhy

When a person is asked about hepatitis B, how much does he know about this disease? "I knew absolutely nothing about hepatitis at this point." "I believe that most people know nothing about hepatitis I know I didn't." (5). says one woman who tested positive for the infection. When it comes to hepatitis, there is simply not enough awareness and outreach, unlike for other sexually transmitted life threatening diseases, such as Acquired Immunodeficiency Syndrome.

In the United States alone, an estimated 12.5 million people currently carry the hepatitis B virus, while another 200,000 to 300,000 people are infected each year (that is one out of every twenty people who will get hepatitis B some time during their lives). 11,000 of the newly diagnosed are hospitalized, and 20,000 remain chronically infected. 4,000 to 5,000 sufferers pass away each year from hepatitis B-related chronic liver disease or liver cancer. Hepatitis B is one hundred times more infectious than Human Immunodeficiency Virus. The sudden thrust of facts and figures makes one feel more susceptible, no?

The newly acquired information makes one wonder, what exactly is hepatitis B Virus? HBV is a forty-two nanometer, double-stranded Deoxyribonucleic Acid (genome has four genes: pol, env, pre-core and X, that respectively encode viral DNA-polymerase, envelope protein, pre-core protein, and protein X) containing hepadnavirus, which can exist on almost any surface for up to one month. Its key components are hepatitis B surface antigen (HBsAg), hepatitis B core antigen, and hepatitis B e antigen (HBeAg). It causes acute and chronic hepatitis, and can damage liver cells, which can cause inflammation and impaired function of the liver. The virus is found in high concentrations in blood, serum, semen, and vaginal secretions of infected people, and low intensity can be found in saliva.

Hepatitis B Virus is transmitted in many different ways, the most general categories beginning with horizontal and vertical transmission. It is spread horizontally by blood and blood products and sexual transmission (body fluids), while vertically from mother to infant in the perinatal period. Contact with even small amounts of infected blood can cause infection. It is not possible to get HBV from sneezing, coughing, or holding hands, nor is HBV found in sweat, tears, urine, and respiratory secretions.

Although exposure to the virus can occur in all age, social, and ethnic groups, some are more at risk than others. In the United States, the majority of infections occur in adults with behaviors or occupations that put them at risk. Those in the higher risk category include people who: a) live with someone who has hepatitis B, b) have hemodialysis, c) practice "unsafe" sex, d) use injection drugs, e) have body piercings or tattoos, f) have contact with open sores, g) share toothbrushes, razors, nail clippers, or washcloths, h) receive human bites, i) are in healthcare, dental, emergency care professions, j) are sexually active adults and teens, k) are in adoptive families, l) are children born to mothers who are carriers, m) travel to high-risk countries, n) are immigrants or refugees from areas of high HBV endemicity, or children of such o) are recipients of certain blood products, p) are clients or staff of institutions for the developmentally disabled, q) are inmates in long-term correctional facilities, r) are homosexual or bisexual men, which makes them ten to fifteen times more likely to acquire HBV than the general population, especially if they are promiscuous (up to seventy percent of gay and bisexual men have already been infected with the virus). In addition, children sometimes transmit the disease to one another, but it is unknown as to how that is precisely achieved. High risk also pertains to newborns of infected women, who can give the virus to their babies during the delivery process. For pregnant women who are infected with HBV, it depends on when the illness occurs. If it is early in the pregnancy, chances are less than ten percent that the baby will receive her virus; later, the odds soar to eighty or ninety percent.

So, if the chances are so favorable that one will contract hepatitis B, why is the majority of world population not dying out from this virus? The answer supplied is simple at the shell, yet complex at the core. As aforementioned, there are two types of viral hepatitis, type B: acute and chronic. Acute hepatitis B is the short and early infection, which manifests itself about one to six months (incubation period of forty-five to one hundred and sixty days, average of ninety days) from the time of infection. Initial symptoms include nausea, vomiting, fever, abdominal pain, loss of appetite, fatigue, muscle and joint aches, followed by jaundice, dark urine, and light stools. Most people are able to make the bug subside after two to three weeks, return the liver to normal in sixteen weeks, and dispose of it within six months. Still, acute hepatitis B ranges from sublicinal disease only detectable by liver function test to fulminant acute hepatic necrosis in about one to two percent of the cases. Patients may suddenly collapse with fatigue and develop symptoms. Acute fulminant hepatitis can be life-threatening due to liver damage, particularly if not treated immediately, because it could lead to liver failure; sometimes this may require a liver transplant, if one is available. Roughly ninety to ninety-five percent of acutely infected people will develop antibodies and totally clear the virus from their bodies. While they may experience some symptoms, they will recover without complications. The remaining five to ten percent will become chronically infected.

Chronic Hepatitis B symptoms appear within two to six weeks after contact, and the virus stays in the blood beyond six months, usually life-long. It induces many symptoms, which only about half of the infected population experiences. Some include fatigue, malaise, joint aches (arthralgias), low grade fever, nausea, vomiting, loss of appetite, abdominal pain (anorexia abdominal discomfort), bloated and tender belly, which progress often to jaundice, and dark urine due to increased bilirubin. Chronic HBV's broad range of effects includes creating clinically insignificant or minimal liver disease in people, who never develop complications, and clinically apparent chronic hepatitis, some of which will go on to develop cirrhosis. Many patients from the first category never develop symptoms or abnormalities, but the evidence of hepatitis will be apparent on liver biopsy, and they are still potentially infectious to others. The condition is commonly referred to as chronic carrier state. Patients are referred to as just "carriers." "These people may switch from "non-replicative to "replicative" infection states and vice versa," (5). which will bring them from carrier states to dangerous states, and reverse. Sometimes, HBV carriers will spontaneously clear the infection from their bodies, but this is rare.

Individuals who have had hepatitis B virus infection have a higher incidence of hepatocellular carcinoma (primary liver cancer) compared to the general population. But chronic carriers, especially those with cirrhosis (chronic hepatitis B heightens chances of this scarring of the liver, a permanent liver damage), are at an even greater risk of developing the cancer because the virus steadily attacks the liver; it is reasonable for such individuals to undergo periodic screening. Death from chronic liver disease occurs in fifteen to twenty-five percent of chronic hepatitis B patients.
The risk of chronic infection is inversely related to a person's age at initial HBV infection. More than ninety percent of newborns, about fifty percent of children, and five to ten percent of adults infected with hepatitis B develop the chronic type. As many as twenty-five percent of infected babies will develop liver failure or liver cancer later. The Centers for Disease Control and Prevention (CDC) estimates that one third of all chronic infections in the Untied States come from infected infants and young children. This is why in the year 1991, routine infant hepatitis B vaccination became law, and the same appeared for adolescents in 1995 (the infant vaccine plan is ninety-five percent effective in protecting babies from becoming chronic carriers).
The best prevention method for hepatitis B infection is the hepatitis B vaccine, which has been available since 1982. Many people do not know when or how they acquired hepatitis B; studies demonstrate that "30 to 40 percent of people who have it are unable to recognize risk factors for the disease." (5). More than one half of acute hepatitis B cases alone may have been prevented through routine immunization and correctional health programs. Alpha-interferon and laminvudine, the two legal vaccines in the United States, are effective in up to forty percent of hepatitis B patients (although they cannot cure the disease), and in ninety to ninety-five percent of all healthy recipients. In chronic infection with liver disease in adults, interferon alpha has been demonstrated to induce a long-term remission in twenty-five to forty percent of treated patients, although it is less effective for chronic infections acquired during early childhood.

Many Americans do not realize the gravity of contracting hepatitis B. We do not want another incidence such as the "1942 outbreak of hepatitis B in military personnel," (5). in which 28,585 people contracted the virus. More than twenty million adults and adolescents and sixteen million infants and children have received the vaccine in the United States, and this country contains one of the low hepatitis-infected citizen numbers. The United States' strategy to eliminate hepatitis B virus transmission is comprised of these components: 1) preventing perinatal transmission, 2) routine infant vaccination, 3) catch-up vaccination of children in high-risk groups at any age, 4) catch-up vaccination of all children at eleven to twelve years of age, 5) vaccination of adolescents and adults in high-risk groups. If we stick to this plan and spread the awareness, perhaps there will be no concern at all for this viral hepatitis, type B.

References

1) Health Library at MerckSource

2) The Official Patient's Sourcebook on Hepatitis B

3) Hepatitis B Vaccine Lawsuit News

4) Hepatitis B

5) Immunization Action Coalition

6) Hepatitis B Foundation

7) Hepatitis B: The Facts

8) The New England Journal of Medicine

9) The Journal of Infectious Diseases

10) Childhood Hepatitis B Virus Infections in the United States Before Hepatitis B Immunization

11) Progress Toward Elimination of Hepatitis B Virus Transmission in the United States

12) Impact of Hepatitis B Virus Infection On Women and Children

13) Centers for Disease Control and Prevention

14) Hepatitis B and the Vaccine

15) Medical Library: Hepatitis B

16) Medical Library: Red Book

17) Medical Library: Hepatitis B Virus

18) Medical Library: Viral Hepatitis, Type B




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