Babesia infections and other tick-borne diseases in Sweden

Babesia is a malaria-like, intraerythrocytic parasite with more than 100 different species. It is a zoonosis and some of the species are transmitted to humans by ticks and also as a possible transfusion-transmitted infection. In Sweden the disease has been well known in veterinary medicine for a long time, but only a few but severe cases have been published in humans during the last decades. Common symptoms from human Babesia infections (babesiosis) are fever, chills and myalgia and they vary from subclinical to potentially fatal among those with risk factors such as immunosuppression and splenectomy. Different methods to detect Babesia are visual detection in blood smears, PCR and antibody measurements.

One study from southern Sweden has recently revealed a seroprevalence of 16% of Babesia antibodies among Borrelia-infected persons compared to 2.5% among healthy control individuals [Svensson et al].

These results indicate that there is a need to broaden awareness of Babesia in Sweden. Both in persons exposed to tick bites but also in people receiving blood transfusions with erythrocytes.