Control

Control, prevention and treatment

Control of babesiosis requires control of the vector, which is obtained through the careful application of suitable acaricides.

However, dependence on this method, if it is successful, can create a highly susceptible cattle population vulnerable to renewed transmission of the protozoa should the control program fail, particularly because of the development of acaricide resistance in the tick population.

For best results, simultaneous management of the pastures should be performed, to ensure that the pastures remain free of ticks for some months.

A highly popular method of control in endemic regions is premunition (or deliberate infection) with blood from a carrier animal. This is the most common method of immunoprophylaxis in endemic regions.

It was widely used in areas of Brazil and Mexico due to its low cost and ready accessibility. Based on the idea of giving a first exposure to Babesia spp. through a small, manageable dose, blood was pulled from an infected animal and injected directly into a recently purchased animal. Once the newly acquired cattle are later exposed to a high load of infected ticks, they will be able to mount a more rapid immune response to the protozoa.

Although premunition is one of the few effective methods of control of babesiosis, there are many pitfalls to this practice.

It may be an unsafe procecure if the blood being used is contaminated with other hemotropic agents, including bovine leukemia virus, bluetongue virus, Theileria, Anaplasma, different strains of Babesia spp, as well as newly emerging or unidentified pathogens.

Another problem is misidentification of Babesia within the inoculum - even under veterinary care, when samples are examined microscopically to ensure an adequate inoculation level of the Babesia spp, stain artifacts or the the presence of Howell-Jolly bodies can result in the blood of an uninfected animal being used as an ineffective antigen source.

Certain chemotherapy treatment protocols are occasionally used to treat babesiosis, especially in conjunction with the premunizing vaccines to avoid or decrease the potentially severe responses that can occur.

Some vaccines for the prevention of babesiosis are currently in use, and others are in developmental stages. Brazilian inactivated vaccines are based on either intact strains of Babesia and Anaplasma or immunogenic fractions. Frozen vaccines based only on the infected RBCs fraction given to sucepitible animals are becoming widely used.

Recombinant vaccines are currently being developed. Progress on these will be dependent upon the understanding of specific regulatory and effector mechanisms required for protection. In order to be efficatious, however, a vaccination program must be paired with appropriate cattle management.