Public health officials are currently looking into an outbreak of listeria infections that has affected nine people between May and June this year. Listeria bacteria can cause the disease listeriosis, which is generally caused by eating food contaminated with the microbe.
According to the Finnish Institute for Health and Welfare THL, the average age of the affected persons is 77 and they are from different parts of the country.
"What is remarkable in this cluster is that several [cases of] infections have appeared in a short time in different parts of Finland," THL epidemiological veterinarian Ruska Rimhanen-Finne said.
Altogether 64 people have fallen ill from the bacterial infection in four separate clusters since 2016. This year so far, 36 people came down with the infection between January and July.
"Sixteen of them are part of the fourth cluster being studied," Rimhanen-Finne added.
Every year between 40 and 90 listeria infections are diagnosed in Finland.
"We are now detecting more cases of listeriosis than before because we are now using a new classification method. It was introduced in 2015 and it recognises clusters more readily. This is partly due to the fact that we are analysing more clusters than before," the epidemiologist added.
Listeria bacteria can be widely found in soil and water. The incubation period for listeriosis can be as long as several weeks.
Seniors more prone to disease
In a statement issued on Thursday, the THL said that many people who have fallen ill have reported consuming risk foods. Such items include cured and cold-smoked fish, herring, fish roe and unpasteurised milk as well as cheese made from unpasteurised milk.
With respect to listeriosis, risk foods also include products that have a long shelf life. For example listeria bacteria are regularly identified in aspics or jellied meats in Finland.
"We have stepped up listeria monitoring to be able to connect cases with sources of infection as soon as possible. If it involves a food product that is on the market, we try to have it recalled," Rimhanen-Finne noted.
Listeriosis generally affects the elderly as well as people with impaired immune systems. Pregnant women are also more vulnerable to the disease.
For these groups, even a small amount of the bacteria could result in serious illness, such as a severe generalised infection or even meningitis. Roughly one in four people with a severe case of listeriosis dies from the disease.
