Hepatitis A is usually spread when the virus is taken in by mouth from contact with objects, food or drinks contaminated by the feces of an infected person. A person can get Hepatitis A through:
— Person to person contact. When an infected person does not wash his or her hands properly after going to the bathroom and touches other objects or food.
— Contaminated food or water. Hepatitis A can be spread by eating or drinking food or water contaminated with the virus. Poor sanitary conditions or poor personal hygiene exacerbate the spread.
There are two major modes of transmission of Hepatitis B virus (HBV):
— Transmission through activities that involve puncturing the skin (e.g. injection drug use that involves sharing needles).
— Mucosal contact with infectious blood or body fluids (e.g., semen, saliva), including sex with an infected partner or birth to an infected mother.
In Vietnam, between 5 and 10 percent of the population are ‘carriers’ of the disease. For nearly all Vietnamese affected, it is mucosal contact (saliva) that is the mode of transmission, occurring at an early age or at birth from an infected mother. There are usually no symptoms when the disease is acquired before puberty, but nearly all then become chronic carriers.
In distinction, Hepatitis B is acquired principally in the ‘developed’ countries as an STD resulting in severe symptoms initially but often with total immunity developed upon recovery. Chronic infection may have significant consequences for the individual (cirrhosis, liver failure, liver cancer). There are 350 million persons infected worldwide. An estimated 620,000 persons worldwide die from HBV-chronic related liver disease each year.
Perhaps the most ‘talked about’ hepatitis in the West is Hepatitis C. About 15 to 20 percent of acute infection resolves spontaneously, and the remainder go on to be chronic carriers of the disease, with consequences ranging from mild to very severe.
Current or former injection drug users are known to be at increased risk of infection. So are recipients of blood transfusions or organ transplants before July 1992, when better testing of blood donors became available.
Also known as ‘delta hepatitis’. This is a serious liver disease caused by infection with the Hepatitis D virus (HDV), which is structurally unrelated to the Hepatitis A, B, or C viruses. Hepatitis D, which can be acute or chronic, is uncommon in most of the world. HDV is an incomplete virus that requires the helper function of HBV to replicate and only occurs among people who are infected with the Hepatitis B virus (HBV).
Vaccine: Unavailable (but HDV is preventable in persons who are not already HBV-infected, through Hepatitis B vaccination)
Hepatitis E is most common in developing countries with inadequate environmental sanitation. Hepatitis E epidemics have been reported in Asia, the Middle East, Africa and Central America. Some epidemics of Hepatitis E have involved tens of thousands of people affected over a short period of time. People living in refugee camps or overcrowded temporary housing after natural disasters can be at particular risk.
The Hepatitis E virus is usually spread by the fecal-oral route. The most common source of infection is fecally-contaminated drinking water.
Dr. Brian McNaull is Medical Director at Family Medical Practice, which is located in Vietnam’s major cities. For information or assistance call (04) 3843 0748 (Hanoi), (08) 3822 7848 (Ho Chi Minh City) or (0511) 3582 699 (Danang). Alternatively, click on vietnammedicalpractice.com