Babesiosis: Recent Insights into an Ancient Disease

Ever since the discovery of parasitic inclusions in erythrocytes of cattle in Romania by Victor Babes at the end of the 19th century, newly recognised babesial pathogens continue to emerge around the world and the substantial public health impact of babesiosis on livestock and man is ongoing. Babesia are transmitted by ixodid ticks and infection of the host causes a host-mediated pathology and erythrocyte lysis, resulting in anemia, hyperbilirubinuria, hemoglobinuria, and possibly organ failure. Recently obtained molecular data, particularly for the 18S rRNA gene, has contributed significantly to a better understanding of the sometimes puzzling phylogenetic situation of the genus Babesia and new information has been added to help determine the taxonomic position of many species. Moreover, it seems that owing to higher medical awareness the number of reported cases in humans is rising steadily. Hitherto unknown zoonotic babesias are now being reported from geographical areas where babesiosis was not known to occur and the growing numbers of immunocompromised individuals suggest that the frequency of cases will continue to rise. This review covers recent insights into human babesiosis with regard to phylogeny, diagnostics and treatment in order to provide new information on well known as well as recently discovered parasites with zoonotic potential.