Bovine anaplasmosis is endemic in South Africa and it has a negative economic impact\non cattle farming. An improved understanding of Anaplasma marginale and Anaplasma marginale\nvariety centrale (A. centrale) transmission, together with improved tools for pathogen detection\nand characterisation, are required to inform best management practices. Direct detection methods\ncurrently in use for A. marginale and A. centrale in South Africa are light microscopic examination\nof tissue and organ smears, conventional, nested, and quantitative real-time polymerase chain\nreaction (qPCR) assays, and a reverse line blot hybridisation assay. Of these, qPCR is the most\nsensitive for detection of A. marginale and A. centrale in South Africa. Serological assays also feature\nin routine diagnostics, but cross-reactions prevent accurate species identification. Recently, genetic\ncharacterisation has confirmed that A. marginale and A. centrale are separate species. Diversity\nstudies targeting Msp1a repeats for A. marginale and Msp1aS repeats for A. centrale have revealed\nhigh genetic variation and point to correspondingly high levels of variation in A. marginale outer\nmembrane proteins (OMPs), which have been shown to be potential vaccine candidates in North\nAmerican studies. Information on these OMPs is lacking for South African A. marginale strains and\nshould be considered in future recombinant vaccine development studies, ultimately informing the\ndevelopment of regional or global vaccines.
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