Hepatitis A Virus (HAV)
Hepatitis A is a viral liver disease that can lead to mild or severe illness. Caused by the hepatitis A virus, this disease spreads when an uninfected (and unvaccinated) person ingests food or water that has been contaminated with the feces or blood of an infected person. The disease is highly associated with unsafe water, inadequate sanitation, and poor personal hygiene (U. S. National Library of Medicine, 2017a; World Health Organization [WHO], 2017a).
This virus can have significant economic and social consequences in communities since infected individuals can take weeks or months to recover and return to school, work, and their daily lives. The local economy and food establishments identified with the virus can be severely impacted as well (WHO, 2017a).
Epidemiology
Approximately 3,000 new infections occur in the United States annually while 1.4 million cases of hepatitis A occur worldwide every year (Centers for Disease Control and Prevention [CDC], 2017). Hepatitis A virus occurs sporadically as well as in epidemics and tends to occur cyclically. Hepatitis A is one of the most frequent causes of foodborne infection, and epidemics can erupt explosively. For example, in one incident in Shanghai in 1988, approximately 300,000 people were infected. Hepatitis A can also persist in the environment and can resist food-production processes routinely used to inactivate and/or control bacterial pathogens. Geographically, HAV can occur minimally or widely. Consider these findings (WHO, 2017a):
- In areas with high rates of infection, most children (90%) have been infected with HAV before the age of 10 years and have few noticeable symptoms. Epidemics are uncommon because older children and adults are usually immune.
- In areas with intermediate levels of infection (such as developing countries with transitional economies and variable sanitary conditions), children often do not get infected in childhood. However, they may get infected as adolescents or adults and larger outbreaks of HAV can occur.
- In areas with low levels of infection (such as developed countries with good sanitary and hygienic conditions) the disease is more common among adolescents and adults in high-risk groups (such as injecting drug users).