Medicine for Africa - Medical Information Service

EPATITIS    

Definition:

Hepatitis A is an acute viral liver disease, caused by the so-called hepatitis A virus (HAV).  The incubation period (the time between infection and the appearance of symptoms) is between two and six weeks, while the disease itself can last anywhere from a few weeks to several months.  Unlike hepatitis B or hepatitis C, it does not evolve into a chronic infection, cirrhosis of the liver, or permanent liver failure.

HAV infection is a highly contagious disease that affects the liver’s ability to function properly for its regular detoxification tasks and the production of a large variety of enzymes, proteins and other important factors for a well functioning metabolism.

HAV is a non-enveloped, single-stranded, protein shell protected RNA (ribonucleic acid) virus of the Picorna virus family.

After the virus has been ingested by mouth (in fecal infected food), it travels through the blood stream to the liver and multiplies in liver cells (hepatocytes) and liver macrophages (Kupffer cells).  Viral particles (virions) are then secreted in the bile, released into the intestinal tract and excreted in the patient’s stool, thus completing the cycle of infection.   

The hepatitis A virus is resistant to detergents, acid solutions (to pH of 1), solvents such as ether and chloroform, drying and temperatures of up to 60º C (140ºF); it can also survive in fresh and salt water for several months.

             Transmission:

HAV is most commonly transmitted from person to person by the fecal-oral route via (feces) contaminated food or drinking water.  Thus, proper hygiene and an effective sewage or latrine system is adamant to prevent the outbreak of this disease (see Prevention).  Transmission via blood or blood products can occur, but is extremely rare.

While worldwide, nearly 10 million people are affected by HAV every year, in developing countries and regions with poor hygiene standards, the incidence of HAV infection approaches 100% of the population.  Usually, the infection is contracted in early childhood, at which time it proceeds with little or no signs or symptoms (in over 90% of children), and confers lifelong immunity.  Thus, HAV is not as significant to this indigenous population, than to people of developed countries, who usually contract the disease at an older age during trips to countries with a high incidence of HAV. 

HAV can also be transmitted via sexual intercourse with an infected person, thus it could also be considered a ‘sexually transmitted disease’, and it can be transmitted via drug paraphernalia shared among infected and non-infected drug abusers.

Other potential ways of transmission include infected drinking water (see above), and raw or undercooked seafood, especially shellfish.

Overall, people who are at an increased risk of becoming infected with HAV include:

• Sexual partners of people who are infected with HAV;
• People who live in a household with HAV infected people;
• International travelers, especially if travelling to developing countries;
• Users of illicit (injected) drugs;
• People who come in contact with HAV infected people at work, dormitories, prison, or other close contact places and/or events.

In general, the liver heals completely without long-lasting damage within one or two months of a recovery phase.  Since the virus elicits a life-long lasting immunity within the patient’s body, there will be no virus left or chance of becoming infected again.

Rarely, an acute hepatitis A infection may exacerbate into a fulminant, life-threatening case of hepatitis – this risk is usually only present in people with pre-existing chronic liver disease or a previous liver transplant.

Symptoms:

Many patients, especially young children in developing countries, never express identifiable signs and symptoms of an active hepatitis A infection.

If symptoms occur, they can be very non-specific and mistaken for other illnesses, such as influenza.  These non-specific general symptoms may include:

• General fatigue and tiredness;
• Low-grade fever;
• Diffuse abdominal pain and/or discomfort;
• Nausea and vomiting – in severe cases, this can lead to dehydration;
• Loss of appetite, and loss of weight;
• Diarrhea;
• Headaches, depression and irritability;
• Jaundice and skin itching;
• Decreased frequency of urinating dark colored urine;
• Sharp pains in the right upper quadrant of the abdomen.

While the above listed symptoms usually last for about two months, in about 15% of cases, they can come and go for as long as six to nine months.

Diagnosis:

Immunoglobulin M (IgM) antibodies can be detected in the blood of patients with an acute HAV infection within about one to two weeks following the initial infection.  This test can remain positive for up to 14 weeks.

Following the identification of IgM, the presence of IgG (immunoglobulin G) antibodies indicates that the acute phase of the infection is over, and that the patient has achieved immunity to future infections.  However, the IgG antibody can also be identified in patients who have received vaccination against the hepatitis A virus.

General blood tests reveal a markedly increased level of the liver enzyme alanine transferase – ALT, due to the liver cell damage incurred by the virus, and an increased level of bilirubin.

Treatment:

There is no specific therapy available for treating a hepatitis A infection.  Fortunately, most patients do not require any treatment except to probably relieve accompanying symptoms – supportive treatments such as:

• IV fluids if dehydration is present (due to excessive vomiting) – may require hospitalization;
• Medical treatment to control nausea and vomiting;
• Pain killers for headaches, etc.

Self-care treatment at home should include:

• Ample resting;
• Drinking of plenty of clear fluids (water) to prevent dehydration;
• Abstain from taking drugs that may cause harm to the liver, e.g. acetaminophen (Tylenol®);
• Abstain from drinking alcoholic beverages and avoid any physical stress, such as vigorous or prolonged exercise.

Prevention:

There is a very effective vaccination available for preventing a HAV infection – this vaccination is recommended for all children after age 1, for international travelers to certain countries, and people who may be generally at risk of becoming infected.  The vaccines contain no live virus, and thus are very safe, without serious adverse side effects; they are given in a series of two shots, six to 18 months apart from each other.  Protection against HAV starts about two to four weeks after the first vaccination, the second is only necessary to insure long-lasting protection (for up to 20 years).

While the vaccines are only effective if administered prior to an infection, patients who have become exposed to the HAV without having received a previous vaccination, can still be given an immune globulin, ideally within two weeks of exposure to the infection.

HAV can be inactivated by chlorine treatment of drinking water, or heating food or water up to 85ºC (185ºF) which will kill the virus.  Also, formalin, peracetic acid, beta-propiolactone and ultraviolet (UV) radiation can inactivate or kill the virus.

Travelers to potentially infectious developing countries should abstain from eating fruits and vegetables unless they are cooked or peeled, and should not drink untreated water or use ice cubes in their drinks.

In general, practicing good hygiene, such as washing one’s hands often after using the toilet, or prior to preparing food or eating, is one of the best and cheapest ways to protect oneself against an infection with HAV.

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