Babesia microti: morphology, distribution and host relationship in Germany.

A short review has been given about recent studies on Babesia microti in natural animal host's near Munich (Southern Germany). An infected area has been studied in order to elucidate the outdoor relationship between the local strains and their preferred hosts, the European field vole Microtus agrestis. The seasonal variation of the parasites prevalence in voles shows a rise in the early summertime (71% of the catches infected). Roundish forms predominate in the erythrocytes. Multiplication never takes place by binary fission, but in "Maltese cross" form or budding-like. Normally the parasite is enveloped with a simple elementary membrane only, as shown by electron microscopy. The arthropod host is still not identified, infections of human beings not observed. This is the first finding and full description of B. microti in Germany.