By NewsDesk  @infectiousdiseasenews

The Norwegian Institute of Public Health has reported an outbreak of hepatitis A. So far, infection has been detected in ten people living in several counties. In addition, two more people are suspected of belonging to the outbreak.

An outbreak investigation has been initiated, but so far there is no suspected source of infection.

The samples were taken in the period April to September 2021 and sequencing shows hepatitis A virus (HAV) with identical sequence (genotype 1A) in all. This suggests that they may be infected from the same source. In addition, there are two samples for which the sequencing results are not yet ready. The people are between 25 and 80 years old, the median age is 53 years and 60 percent are men. The infected live in different parts of the country: Viken (6), Oslo (1), Trøndelag (2), Vestfold and Telemark (1), Innlandet (1) and Troms and Finnmark (1).

None of the infected have traveled abroad. Based on where the infected people live, it is likely that they are infected through a food that is widely distributed, says senior adviser Heidi Lange at the Department of Infection Control and Emergency Preparedness at the National Institute of Public Health.

The Norwegian Institute of Public Health collaborates with the municipal health service and the Norwegian Food Safety Authority to map whether patients can have a common source of infection. Patients are interviewed about what they ate or drank before they became ill. The time from a person becoming infected with hepatitis A and until the disease develops (incubation period) can be from two to six weeks, usually around four weeks.

Investigation work can be complicated and time consuming, and we are not always able to find the source of infection or to clarify whether it is one common source, says Heidi Lange and adds that the long incubation period makes the work of finding the source of infection particularly complicated.

Internationally, HAV has in recent years been proven in various types of shells, lettuce, semi-dried tomatoes and dates as well as in frozen berries. In 2014, we had the last outbreak of hepatitis A in Norway. That outbreak was related to frozen berries .