The African buffalo parasite Theileria. sp. (buffalo) can infect and immortalize cattle leukocytes and encodes divergent orthologues of Theileria parva antigen genes

Abstract

African Cape buffalo (Syncerus caffer) is the wildlife reservoir of multiple species within the apicomplexan protozoan genus Theileria, including Theileria parva which causes East coast fever in cattle. A parasite, which has not yet been formally named, known as Theileria sp. (buffalo) has been recognized as a potentially distinct species based on rDNA sequence, since 1993. We demonstrate using reverse line blot (RLB) and sequencing of 18S rDNA genes, that in an area where buffalo and cattle co-graze and there is a heavy tick challenge, T. sp. (buffalo) can frequently be isolated in culture from cattle leukocytes. We also show that T. sp. (buffalo), which is genetically very closely related to T. parva, according to 18s rDNA sequence, has a conserved orthologue of the polymorphic immunodominant molecule (PIM) that forms the basis of the diagnostic ELISA used for T. parva serological detection. Closely related orthologues of several CD8 T cell target antigen genes are also shared with T. parva. By contrast, orthologues of the T. parva p104 and the p67 sporozoite surface antigens could not be amplified by PCR from T. sp. (buffalo), using conserved primers designed from the corresponding T. parva sequences. Collectively the data re-emphasise doubts regarding the value of rDNA sequence data alone for defining apicomplexan species in the absence of additional data. ‘Deep 454 pyrosequencing’ of DNA from two Theileria sporozoite stabilates prepared from Rhipicephalus appendiculatus ticks fed on buffalo failed to detect T. sp. (buffalo). This strongly suggests that R. appendiculatus may not be a vector for T. sp. (buffalo). Collectively, the data provides further evidence that T. sp. (buffalo). is a distinct species from T. parva.

Elucidating cryptic dynamics of Theileria communities in African buffalo using a high‐throughput sequencing informatics approach

“…sp. (buffalo) (Mans et al, : nodal support NJ = 65%; Mans et al, : NJ bootstrap value of 64); however, analysis using alternative markers has differentiated these as unique taxa (Bishop et al, ).…”

Monitoring vaccinated cattle for induction and longevity of persistent tick‐transmissible infection: Implications for wider deployment of live vaccination against East Coast fever in Tanzania

“…Nevertheless, the majority of the cattle exhibited parasites with 1–2 MS7 alleles each. This possibly reflects a phenomenon that only a limited subset of T. parva genotypes can be transmitted by ticks to cattle, although the diversity of T. parva circulating between vector ticks and wildlife reservoirs is highly diverse (Allsopp et al, ; Bishop et al, ; Conrad et al, , ).…”

Antigen gene and variable number tandem repeat ( VNTR ) diversity in Theileria parva parasites from Ankole cattle in south‐western Uganda: Evidence for conservation in antigen gene sequences combined with extensive polymorphism at VNTR loci

“…The African cape buffalo are important wildlife reservoirs of T. parva and are typically infected with parasite populations exhibiting higher antigenic diversity than T. parva that can be transmitted between cattle by ticks (Obara et al., ; Pelle et al., ). In addition, it has recently been demonstrated that cattle immunized by (ITM) using the Muguga cocktail are susceptible to challenge with buffalo‐derived parasites (Bishop et al., ; Sitt et al., ). Genome sequencing of schizonts purified from cell lines (Hayashida et al., ), a comprehensive study of variation within the genes encoding the Tp antigens (Pelle et al., ) and VNTR analyses (Oura, Tait, Asiimwe, Lubega, & Weir, ) have all confirmed that the cape buffalo harbours a much greater diversity of T. parva genotypes relative to the strains transmissible between cattle by ticks.…”