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
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Date
2020
Journal Title
Journal ISSN
Volume Title
Publisher
Transboundary and emerging diseases
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.
Description
Keywords
Ankole cattle, East Coast fever, Genetic diversity, MHC1, Theileria parva, Tp1, Tp2, VNTR
Citation
Nanteza, A., Obara, I., Kasaija, P., Mwega, E., Kabi, F., Salih, D. A., ... & Lubega, G. W. (2020). 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. Transboundary and emerging diseases, 67, 99-107. DOI: 10.1111/tbed.13311