Hepatitis A is an infection caused by a virus affecting the liver, causing inflammation of the organ and often jaundice (yellowing of skin). It can be caused and spread by poor hygiene, contaminated food and contact with an infected person.

The first case was confirmed in Viljandi this past February, and it was linked to travel abroad. However, since August 25, the number of cases has spiked dramatically: 28 cases reported across the county, 25 of these in the town of Viljandi.

Viljandi Mayor Lembit Kruuse called for the formation of a disease prevention task force, with a particular focus on preventing the spread of the disease.

Last week alone, in numerical terms, the number of those infected in Viljandi increased by 30 percent. Unfortunately, officials said, the disease has an incubation period of 50 days, meaning it will take some time to assess the impact.

The most effective action to counter hepatitis-A is a vaccine, taken in two doses at six- to 18-month intervals. According to studies, immunity generally develops within one month of the first dose. The duration of the immunity is at least 20 years.

In terms of prevention, health officials stress the importance of washing hands with soap and water after using the washroom, before food preparation, and after eating.

In Estonia, cases of hepatitis-A infections have been low in number over recent years, with the majority of those being travel-related: 10 cases in 2007, 13 in 2008, 19 in 2009 and six in 2010.

The last major outbreak was in 1993 in Sõmeru, when contaminated drinking water caused 614 people to become ill.

Andres Kahar