Molecular epidemiology of bovine anaplasmosis

Bovine anaplasmosis presents a worldwide distribution. However, specific models for studying the epidemiology of the disease are not available. Epidemiological modeling encounters some difficulties due to a lack of culturing techniques for Anaplasma marginales, the causative agent, as well as for the lack of typing techniques to characterize strains. The chronic carrier state and the population dynamics of mechanical and biological vector also create difficulties. In addition, conventional serology and blood smear diagnostic techniques fail to detect all chronica carriers. Fortunately the needs for the accurate typing of isolates and for detecting chronica carriers made it possible to encourage the development of new tools based on molecular epidemiology principles. A. marginali isolates can now be typed by using panels of monoclonal antibodies, and the genes coding for some major surface proteins can be expressed or analyzed by looking at the nucleotide arrangement level. In the same manner, the latest techniques for detecting A. marginale chronic infections use DNA and RNA probes, and PCR-based methods to detect A. marginali DNA from bovine blood samples with extremely low rickettsaemias. Currently all these new epidemiological tools are being incroporated to experimental models to analyze their applicability for epidemiological studies in the near future

Bovine babesiosis: a review of recent advances

Bovine babesiosis, caused by parasites of the genus babesia, is one of the world's most severe tick-borne problems of cattle in temperate to tropical areas. In the America Babesia bovis and B bigemina are the causative agents, with the former considered to produce the greatest economic impact. The great complexity of the relationship causal agent-vector-host has severely hindered the efforts towards the production of a safe, long-lasting, solid-protection inducing vaccine. Recent importan contributions that have encourage the study of these agents include the development of in vitro cultivation systems, procedures for the isolation of single infected-erythrocytes, density gradient-based centrifugation systems for the isolation and concentration of both infected erythrocytes and merozoites, isozyme detection and differentitation systems that help discrimate between parasite species, and development of DNA-based diagnostics and characterization protocols. Currently, the study of the cellular immune response against these parasites is taking new endeavors in order to discern the relationship between B cells, T cell, macrophages and their product and parasites leading to the establishment of solid, long-lasting protection. In an attempt to design a rational vaccine, T cell lines and clones are being established, and phagocytosis of infected erythrocytes and their antigens studied to try to pinpoint relevant epitopes