An ultrastructural study of the development of Babesia occultans in the salivary glands of adult Hyalomma marginatum rufipes.

The development of Babesia occultans in the salivary glands of adult Hyalomma marginatum rufipes was studied with the electron microscope. Sporogony involved a process of multiple fission in which sporozoites formed from the periphery of a polymorphous sporont. Different stages of development were found concurrently in individual acini as well as within individual acinar cells. Mature sporozoites were found on Day 3 post-tick attachment and measures 3.0-3.5 X 1.5 micron. The apical complex consisted of a polar ring and 4-6 rhoptries. Micronemes were concentrated anteriorly and 1 or 2 spherical bodies were identified in each sporozoite. The general pattern of development was similar to that described in several other Babesia spp. but distinct morphologic differences were noted.