Piroplasmida

Abstract: Publisher Summary The piroplasms are protozoa that are highly pathogenic to cattle, sheep, goats, and occasionally even to man. They comprise two genera—namely, Theileria and Babesia . The diseases they induce, known collectively as “theilerioses” and “babesioses,” cause fevers and lead to important economic losses in the tropics, subtropics, and southern Europe. This chapter highlights the differences between the life cycles of Babesia and Theileria species with respect to their morphology, studied by means of light and electron microscopy. The chapter describes the life cycle of piroplasms. They have a typical sporozoan life cycle comprising three phases: (1) Schizogony, an asexual reproduction phase in the vertebrate host. (2) Gumogony, the formation and fusion of gametes inside the intestinal cells of ixodid ticks. (3) Sporogony, an asexual reproduction in the salivary gland of the tick leading to the infectious, saliva-transmitted sporozoites. Comparative biological and morphological studies show that the economically important piroplasms comprise three groups: (1) Babesia species sensu strictu ; (2) Bubesia equi , B. microti ; and (3) Theileria species.