could most of you would name gonorrhoea, syphilis and Acquired Immunodeficiency Syndrome (AIDS).

Some would remember to add herpes, chlamydia, trichomonas, genital warts and pubic lice to their list. Health professionals may add the more exotic tropical STDs. But I dare say most lay people and some health care professionals would overlook Hepatitis B virus infection.

Hepatitis B could be considered the overlooked STD as it receives comparatively little media attention and may even be overlooked in medical settings dealing with STDs. Yet it is not a rare or exotic illness and its prevalence is steadily increasing.

Hepatitis B virus has been known for decades as one of the viral causes of serious liver disease, and infection with it can lead to chronic hepatitis, liver failure and death. Infection with this virus also increases the chance of acquiring liver cancer.

In the past Hepatitis B virus (HBV) infection was considered a disease that resulted almost entirely from exposure to contaminated blood through the sharing of needles in drug addicts or through transfusion of tainted blood products. Now that blood bank products can be reliably screened for HBV it has become increasingly obvious that the virus is spread through other means as well.

Today the principal ways of acquiring HBV infection are through sexual contact with an infected partner, through sharing needles for drug injection and through exposure in the work place. Any situation which might bring an individual in contact with another person's blood or body fluids places him at risk of contracting HBV. In an infected person the virus is present in blood, semen, vaginal secretions and wound drainage primarily. In lesser quantities it is also found in saliva. In pregnant women infected with HBV there is a risk of infecting the unborn baby. It is therefore important for pregnant women to be screened prenatally for HBV so that if they are infected their newborn baby can be immediately treated to minimise the risk of infection.

HBV is a hearty virus and can survive in a dried state on objects outside the body for more than a week. Hence it is important to guard against cuts or punctures with needles or objects which could be contaminated with the virus.

There are parts of the world where HBV is extremely prevalent. Alaska natives, Pacific Islanders, persons from East Asia, Africa and parts of South America have high rates of HBV infection. However, due to travel and immigration the incidence of HBV infection in Western countries is rising steadily.

Approximately 300,000 new cases of HBV infection occur annually in the USA and 5,000 people die each year due to chronic liver disease resulting from HBV.

While the number of Hepatitis B positive individuals in Bermuda is very small in comparison to the USA, here too the picture is one of increasing rates.

In our part of the world most people contract HBV as adolescents and young adults. The groups at highest risk for HBV are intravenous drug users, persons who have had more than one sexual partner in the past six months or who have had a recent STD, and homosexual men. Also at risk are those whose jobs involve contact with blood or body fluids, persons who travel to countries where HBV has a high prevalence, persons who live in the same household with a Hepatitis B infected individual or persons on dialysis or who must receive frequent blood products.

Of course for the vast majority of young people the greatest risk of exposure to HBV occurs through sexual contact, and it is often associated with other STDs. As with any STD the most reliable prevention is sexual abstinence or, failing that, faithful condom use and a mutually monogamous relationship with a healthy partner.

Once infected with HBV the virus incubates for 4 weeks to 6 months and no obvious illness occurs during this period. After this time symptoms of infection are variable. Most infected persons have no symptoms or very mild symptoms which include nausea, loss of appetite, fatigue, low grade fever, muscle or joint aches. In some these mild symptoms are followed by yellowing of the skin (jaundice) and tenderness in the right upper part of the abdomen where the liver is located. For most infected individuals recovery is complete after 3 to 4 months, but for 10% of individuals infected in adolescence or adulthood the acute infection is followed by a state of chronic infection with HBV. These HBV carriers may go on to infect unsuspecting sexual partners or household contacts. They are also at greater risk of developing progressive liver disease, liver failure or liver cancer.

There is fortunately one bit of good news about HBV infection which is that it is the only STD for which there is a safe and effective vaccine. The Hepatitis B vaccine has been in use in high risk groups for over a decade. It is now recommended by most experts that it be administered early in life so that eventually the HBV can be eliminated. While the exact vaccination schedule may vary between health care providers almost all agree that the Hepatitis B vaccine has broader indications than just the traditionally high risk groups.

If you would like to learn more about protecting yourself or your children from Hepatitis B virus see your doctor or telephone the Health Department's School Clinic.

Dr. Cheryl Peek-Ball Maternal Health & Family Planning Department of Health