According to the surveillance data compiled by the Taiwan Centers for Disease Control (Taiwan CDC), during October 1 and November 30, 2014, a total of 30 indigenous cases of acute viral hepatitis A were confirmed. Of the cases, 25 were hospitalized, which is a lot higher than the number reported during the same period last year (4). According to the epidemiological investigation, most patients consumed raw bivalves such as oyster and clams during the disease incubation period. Hence, Taiwan CDC urges the public to pay attention to personal dietary hygiene and consume only thoroughly cooked bivalves. If suspected symptoms develop, please seek prompt medical attention to prevent further spread of the disease.  

Bivalves such as oysters and clams concentrate the pathogens that are present in harvest waters. Hepatitis A and norovirus infection are two of the common worldwide diseases that resulted from consumption of bivalves harvested in contaminated waters. Since most bivalve farms in western Taiwan are located near estuaries, the Taiwan Food and Drug Administration (TFDA) recommends consumers to thoroughly cook bivalves harvested from the area before eating. In addition, TFDA also recommends boiling bivalves for another 3-5 minutes after shells open prior to eating them. Over the recent years, the recreational agriculture and fishery industries in Taiwan have develoedp rapidly, several agriculture- and fishery-themed tourist attractions have opened and become popular among tourists. Therefore, Taiwan CDC urges food business operators to maintain food safety, comply with food hygiene regulations, and avoid offering raw bivalves on the menu. Further, the public is advised to practice good personal and dietary hygiene, avoid consuming raw foods and drinks, and wash hands before meals in order to ensure their own health.  

Hepatitis A virus infection is usually transmitted by the fecal-oral route with an incubation period ranging from 15 to 50 days. Initial symptoms may include fever, general fatigue, loss of appetite, vomiting, and abdominal pain. Days after infection, jaundice develops. Most cases recover on their own and people who have hepatitis A infection become immune for the rest of their life. Although the mortality rate for hepatitis A is low, elderly people or chronic carriers of hepatitis B virus and hepatitis C virus are at increased risk for fulminant hepatitis, which could lead to death. As public health in Taiwan has improved in recent years, most children and young adults do not have hepatitis A antibodies. Nevertheless, hepatitis A can be effectively prevented through vaccination. People who do not have hepatitis antibodies are recommended to receive two does of self-paid vaccine to lower the risk of infection.  

If symptoms pertaining to hepatitis A infection develop, please seek immediate medical attention, and voluntarily inform the physician of relevant travel and food intake history in order to ensure prompt diagnosis and treatment. On the other hand, physicians are advised to reinforce the reporting of hepatitis A cases to facilitate timely epidemiological investigation and implementation of public health interventions by the relevant authorities, which will prevent further transmission of the disease. For more information, please visit the Taiwan CDC’s website at http://www.cdc.gov.tw or call the toll-free Communicable Disease Reporting and Consultation Hotline, 1922, or 0800-001922.