Severe babesiosis caused by Babesia divergens in a host with intact spleen, Russia, 2018

•Severe babesiosis caused by Babesia divergens in a host with an intact spleen in Russia.•There was heavy multiple invasion, of up to 14 parasites, inside the erythrocyte.•The piroplasm 18S rRNA sequence from our patient was identical B. divergens EU lineage. We report a case of severe babesiosis caused by the bovine pathogen Babesia divergens with the development of multisystem failure in a splenic host. Immunosuppression other than splenectomy can also predispose people to B. divergens. There was heavy multiple invasion of up to 14 parasites inside the erythrocyte, which had not been previously observed even in asplenic hosts. The piroplasm 18S rRNA sequence from our patient was identical B. divergens EU lineage with identity 99.5–100%.