The piroplasms: “A long story in short” or “Robert Koch has seen it”

The piroplasms (named because of their pear-shaped intraerythrocytic stages) are protozoa that are mainly highly pathogenic to ruminants such as cattle, camels, sheep, goats, and deer. Furthermore, some species may infect horses, dogs, cats, pigs, and even humans. The diseases they induce, known collectively as theileriosis or babesiosis, cause fevers as main leading symptoms and bring about important economic losses due to their high mortality rates in the tropics and subtropics or even in the more temperate regions of America, Europe, Asia, or Australia. All piroplasms have at least one stage which is situated in the red blood cells of their hosts and are transmitted by the sucking process of ixodid ticks. In general the relation vector-parasite is very close and thus transmission mainly occurs by species specific vectors. Most of the stages recognized today as belonging to the life cycle of Babesia and Theileria species were already known at the beginning of the century.