What is Hepatitis A Virus (HAV)? Transmission, Symptoms, Vaccine
The hepatitis A virus or HAV is one of the five types of hepatitis viruses that infects the liver and causes inflammation. It is a highly infectious virus belonging to the picornavirus group of enteroviruses. Although hepatitis A is seen as the one of the least dangerous of the hepatitis viruses, it should not be ignored as it can lead to acute liver failure in rare cases. However, HAV does not lead to chronic hepatitis.
Transmission of Hepatitis A
How is hepatitis A transmitted?
The hepatitis A virus (HAV) is transmitted by ingesting food or water contaminated with the virus. This is as a result of fecal contamination as the virus is present in the feces of a person infected with HAV. Transmission is therefore by the fecal-oral route. It may also be transmitted via saliva and sexual intercourse. Other methods of transmission are via blood but this is uncommon.
It is important to note that an infected adult is often asymptomatic in the early stages but passes out the virus in the feces. This can continue for up to 2 weeks after the onset of symptoms. Children, usually under the age of 6 years, may show no symptoms yet the virus is present in the feces. With HAV however, a person is not a chronic carrier.
Hepatitis Causes and Risk
What causes hepatitis A?
The hepatitis A virus (HAV) is present throughout the world, however, it is more frequently seen in areas of poor sanitation and hygiene. These endemic areas may include high risk countries where substandard practices and a lack of regulation can place any person at risk, even the city-dwelling traveler. It is also seen in developed countries in areas of overcrowding, especially if there are outbreaks particularly during times of natural disasters.
What are the risk factors for contacting HAV?
There is a risk of contracting HAV if you :
- drink contaminated water, especially from untreated sources like rivers and lakes
- eat food prepared by an infected person who does not practice proper hygiene
- have sex with a person who is infected
- have regular close contact with a person who is infected
- receive a blood transfusion with contaminated blood (rare)
Hepatitis A Symptoms
What are the signs and symptoms of hepatitis A?
Hepatitis A is usually asymptomatic or may cause mild symptoms in adults. The incubation period is 2 to 4 weeks, during which time an infected person, often shows no symptoms. Non-specific symptoms indicative of acute infection include headache, muscle pain, joint pains, nausea, fever and loss of appetite. If present, it is often mistaken for the seasonal flu (influenza) or common cold.
Symptoms such as vomiting and diarrhea tend to present later and is then followed by typical symptoms of liver dysfunction like jaundice, pale stools and dark urine. Abdominal discomfort, pain or tenderness (refer to liver pain) is also usually present at this stage.
Read more on hepatitis symptoms.
Hepatitis A Diagnosis
How is hepatitis A diagnosed?
A blood test will detect antibodies to the HAV antigen (anti-HAV). These are specific IgM antibodies that indicate acute infection. IgG antibodies may indicate previous HAV infection.
Hepatitis A Treatment
How is hepatitis A treated?
Hepatitis A infection does not require any specific treatment. A person will recover with proper bed rest, good nutrition and fluid intake. Patients who are immunocompromised, like in HIV infection, require careful monitoring and supportive treatment for the symptoms, especially for dehydration from vomiting and diarrhea.
Hepatitis A Vaccine
What is the hepatitis A vaccine?
The hepatitis A vaccine prevents HAV infection and should be considered in a person who is at risk. This includes frequent travelers to endemic areas, health care workers and those who receive regular blood transfusions. There are single-antigen and combination vaccines available for HAV immunization. Two shots are administered – a first shot followed by a booster shot 6 to 12 months later. It is recommended that children are vaccinated at 1 year of age, especially if they live in endemic areas.
Hepatitis A Prevention
How is hepatitis A prevented?
Vaccination is an important part in preventing HAV. Previous infection earlier in life offers natural protection against the virus. However, practicing good hygiene and undertaking sensible precautions also play an integral role in preventing HAV infection. This may include :
- Drinking water from only reputable sources when traveling abroad (bottled water is often the easiest).
- Do not eat food from outlets with questionable sanitary practices like street vendors, especially in endemic countries.
- Always cook food, especially shellfish, thoroughly.
- Wash your hands after using the toilet and regularly during the course of the day.
- Practice safe sex and do not have sex with multiple partners