Babesiosis is an emerging tick borne zoonotic disease caused by intraerythrocytic parasites of the genus Babesia. Babesiosis is one of the most common infections of free-living animals worldwide but is perhaps most prevalent in rodents, carnivores, and cattle. This fact increases the concern about the emerging zoonosis. Like the malaria agent Plasmodium, the parasite Babesia attacks and damages the host’s red cells. Babesia microti and Babesia divergens cause human infections. In the USA, an endemic region of this infection, most human cases are due to Babesia microti. In Europe, babesiosis is considerably rare and is caused by Babesia divergens, with splenectomized patients being at highest risk. The spectrum of disease is broad, ranging from an apparently silent infection to a fulminant, malaria-like disease. Symptoms include fever, chills and icterus. The treatment of choice is clindamycin and quinine. The laboratory diagnosis is based on direct detection of the parasite from blood smears. Due to increasing international travel, even relatively uncommon parasitic infections can be found in the Czech Republic and babesiosis is just one of them.

        Key words: human babesiosis – Babesia divergens – Babesia microti.