Light and electron microscopic observations on the development of small merozoites of Babesia bovis in Boophilus microplus larvae.

The development of small pyriform merozoites of B. bovis in the granule-secreting cells of the salivary glands of B. microplus larvae, studied with a light microscope, showed a close resemblance to that of B. argentina described by Riek (1966) in the same tick vector. Dvelopment took place through a process of schizogony and resulted in the formation of many merozoites. A study of the ultrastructure of developing merozoites in the schizont revealed the following: a poorly defined outer membrane; a granular osmiophilic inner membrane; anterior and posterior polar rings; rhoptries; micronemes; microtubules; a nucleus; spherical bodies of varying size. The schizonts were membrane-bound but no parasitophorous vacuoles were seen.