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

Abstract

Theileria parva is a tick‐transmitted apicomplexan protozoan parasite that infects lymphocytes of cattle and African Cape buffalo (Syncerus caffer), causing a frequently fatal disease of cattle in eastern, central and southern Africa. A live vaccination procedure, known as infection and treatment method (ITM), the most frequently used version of which comprises the Muguga, Serengeti‐transformed and Kiambu 5 stocks of T. parva, delivered as a trivalent cocktail, is generally effective. However, it does not always induce 100% protection against heterologous parasite challenge. Knowledge of the genetic diversity of T. parva in target cattle populations is therefore important prior to extensive vaccine deployment. This study investigated the extent of genetic diversity within T. parva field isolates derived from Ankole (Bos taurus) cattle in south‐western Uganda using 14 variable number tandem repeat (VNTR) satellite loci and the sequences of two antigen‐encoding genes that are targets of CD8+T‐cell responses induced by ITM, designated Tp1 and Tp2. The findings revealed a T. parva prevalence of 51% confirming endemicity of the parasite in south‐western Uganda. Cattle‐derived T. parva VNTR genotypes revealed a high degree of polymorphism. However, all of the T. parva Tp1 and Tp2 alleles identified in this study have been reported previously, indicating that they are widespread geographically in East Africa and highly conserved.

Antigenic Diversity in Theileria parva Populations From Sympatric Cattle and African Buffalo Analyzed Using Long Read Sequencing

“…Epitope variant VGYPKVKEEII was most frequently observed in cattle (31) and VGYPKVKEEML was most common in buffalo (all 12). Several other studies have demonstrated that -ML is the dominant epitope across East Africa, being the predominant allele detected in cattle in Kenya, Tanzania, Burundi, Democratic Republic of Congo, Malawi, Rwanda and Uganda (Pelle et al, 2011;Elisa et al, 2015;Amzati et al, 2019;Kerario et al, 2019;Atuhaire et al, 2020;Chatanga et al, 2020;Nanteza et al, 2020). Pelle et al (2011) is the most comparable study to ours, having examined Tp1 diversity in parasites isolated from buffalo or from cattle with varying exposure to buffalo-derived T. parva.…”

“…For Tp1 and Tp16, each allele was tested against the reference to check if the mutation was synonymous or non-synonymous. For Tp1, the known epitope region (Nanteza et al, 2020) was selected from each allele sequence to list all unique epitope residues. Ts/Tv ratio was calculated for each source group Tp1 samples-cattle, buffalo, TpM.…”

Antimicrobial Resistance Profile of Foodborne Salmonella spp. and E. coli Isolates from Rodents and Shrews in Morogoro Municipality, Tanzania

“…InvA gene was also targeted for Salmonella spp. PCR was performed using a master mix (Bioneer PreMix, Korea) (James, 2010;Silva et al, 2011;Nanteza et al, 2020). e PCR ampli cation for Salmonella spp.…”