Rotavirus group A (RVA) causes neonatal calves diarrhoea, causing massive economic losses in many countries due to deaths, treatment costs, and stunted growth. However, little is known about Tanzanian cattle's RVA burden and genotypes. The prevalence and genetic diversity of rotaviruses circulating in cattle in Southern and Eastern Tanzania regions were investigated. A total of 272 faecal samples collected from calves (102 from Mbeya, 89 from Iringa, and 81 from Morogoro) were tested for RVA. 30 (11.03%) of the 272 samples tested positive for RVA, 7 (6.8%) of the 30 RVA positive samples were from Mbeya, 23 (28.39%) from Morogoro, and no positive samples were found in the Iringa region. Using RT-PCR, 20 samples were identified as G10 genotypes, while the remaining 10 samples were untypeable with the primers used, whereas all P genotypes were untypeable. To confirm the RT-PCR results, representative samples were chosen and sequenced in the ABI 3130XL using a Big-dye Terminator kit with Sanger dideoxy sequencing method. Phylogenetic analysis and nucleotide comparison revealed that G10 was closely related to and clustered with human G10 strains from neighbouring Kenya, implying that circulating G10 strains may have the potential for zoonotic transmission. When circulating G10 amino acid alignment was compared to bovine vaccine strain B223, our G10 samples had various nucleotide substitutions at antigenic epitopes, which resulted in the acquisition of glycosylation sites suggesting that G10 has the potential to evade neutralization antibodies induced by a vaccine. Our study provided preliminary data on RVA in cattle in Tanzania, paving the way for further research into the rotavirus epidemiology and risk factors associated with RVA in cattle in Tanzania.
Keywords: Cattle, Rotavirus group A, G10 genotype, Tanzania