By Sylvanus Thompson
Hepatitis A is a liver disease caused by the hepatitis A virus. The disease is primarily spread when an uninfected person ingests food or water that is contaminated with the faeces of an infected person. It is therefore closely associated with unsafe water or food, inadequate sanitation and poor personal hygiene.
Hepatitis A occurs worldwide and is one of the most frequent causes of foodborne infection. In developed countries with good sanitary and hygienic conditions, infection rates are low. Disease may occur among adolescents and adults in high-risk groups, such as injecting-drug users, men who have sex with men, people travelling to areas with high rates of infection, and in isolated populations, such as closed religious communities. However, when the virus gets introduced in such communities, high levels of hygiene stops person-to-person transmission and outbreaks die out rapidly.
The hepatitis A virus is transmitted primarily by the faecal-oral route. In families, this may happen though dirty hands when an infected person prepares food for family members. Waterborne outbreaks, though infrequent, are usually associated with sewage-contaminated or inadequately treated water. The virus can also be transmitted through close physical contact with an infectious person, and sexually through anal-oral contact. Casual contact among people does not spread the virus.
Who is at risk?
Anyone who has not been vaccinated or previously infected can become ill with the hepatitis A virus. In areas where the virus is widespread, most hepatitis A infections occur during early childhood. Risk factors include:
- poor sanitation;
- lack of safe water;
- use of recreational drugs;
- living in a household with an infected person;
- being a sexual partner of someone with acute hepatitis A infection; and
- travelling to areas with high infection rates without being immunized.
Symptoms usually appear within 30 days after contact with hepatitis A, but the range can be from 15 to 50 days. The signs and symptoms of the disease range from mild to severe, and can include fever, malaise, loss of appetite, diarrhoea, nausea, abdominal discomfort, dark-coloured urine and jaundice (a yellowing of the skin and whites of the eyes). Not everyone who is infected will have all of the symptoms. The severity of disease and fatal outcomes are higher in older age groups, and adults have signs and symptoms of illness more often than children. Infected children under six years of age do not usually experience noticeable symptoms but they are still able to spread the virus to others. Among older children and adults, infection usually causes more severe symptoms, with jaundice occurring in more than 70 per cent of cases. Hepatitis A sometimes relapses and the person who just recovered may fall sick again with another acute episode. This is, however, followed by recovery. Unlike hepatitis B and C, hepatitis A does not develop into chronic hepatitis or cirrhosis and death from this infection is rare.
A person with hepatitis A can pass the virus to others for one to two weeks before they start to show symptoms. Furthermore, people can remain infectious for up to one week after they get sick.
There is no specific treatment for hepatitis A. However, supportive care such as adequate nutrition and avoiding drinking alcohol during the acute phase of illness may reduce complications. Most people recover after four to six weeks.
The viruses persist in the environment and can withstand food-production processes routinely used to inactivate and/or control bacterial pathogens. Improved sanitation, food safety and immunization are the most effective ways to combat hepatitis A. The spread of infection can be reduced by:
- adequate supplies of safe drinking water;
- proper disposal of sewage within communities;
- personal hygiene practices such as regular hand-washing with soap and warm water after using the toilet, changing a diaper, helping someone who has diarrhea, and before eating or preparing food;
- avoiding raw seafood and vegetables washed in untreated water;
- Using barrier protections, such as condom, and practice good hand hygiene to reduce the risk from fecal / oral sexual transmission.
Two doses of Hepatitis A vaccine, separated by at least six months, are needed for long-term protection. Nearly 100 per cent of people develop protective levels of antibodies to the virus within one month after injection of a single dose of vaccine. Even after exposure to the virus, a single dose of the vaccine within two weeks of contact with the virus has protective effects. However, manufacturers recommend two vaccine doses to ensure a longer-term protection of about five to eight years after vaccination. Hepatitis A vaccine is covered for free in Ontario for certain groups at higher risk of being infected. The cost may also be covered by private health insurances.
The disease can lead to significant economic and social consequences in communities. It can take weeks or months for people recovering from the illness to return to work, school, or day-to-day activities. The impact on food establishments identified with the virus, and local productivity in general, can be substantial. Hepatitis A is one of the most common vaccine-preventable illnesses in travellers. Millions of people have received injectable inactivated hepatitis A vaccine worldwide with no serious adverse events. Vaccination is therefore strongly recommended especially for high risk groups and persons travelling to endemic areas.
( Jamaica-born Sylvanus Thompson is the Associate Director/Food Safety Lead with Toronto Public Health.)