Methods of immunoprophylaxis against bovine anaplasmosis with emphasis on use of the attenuated Anaplasma marginale vaccine.

One of the major obstacles to the development of methods for immunoprophy-laxis against hemotropic diseases has been the lack of techniques for in vitro propagation of the causative agents (Anaplasma, Babesia), or the availability of similar systems for laboratory production of arthropod-associated “prototype” antigens (trypanosomes). A recent accomplishment in this direction has been the development of cell culture methods for Theileria parva, the causative agent of East Coast fever. While this step is considered an important breakthrough providing incentive for more optimistic future endeavors in the entire field, the accomplishment must not be viewed as an indication that this technique can be directly applied to other hemotropic agents. Theileria parva actively invades cellular elements of both the erythrocytic and lymphocytic series, the latter being adapted to in vitro propagation. Anaplasma, Babesia, and Plasmodium are considered to primarily affect the more inert circulating erythrocyte which, rather than offering replication ability in cell culture, continues its in vivo destiny of degeneration.