Molecular Characterization of piroplasms in the Black (Diceros bicornis michaeli) and White rhinoceros (Ceratotherium simum simum) Meta-population in Kenya
Kivata, Mary Wandia
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The eastern black (Diceros bicornis michaeli) and the white (Ceratotherium simum) rhinoceros are critically endangered species mainly due to poaching and loss of habitat. Conservation strategies such as creation of highly secured sanctuaries, intensive management and linking meta-populations by translocations, are yielding positive population growth rate in Kenya. However, diseases are still another impediment to the rhinoceros population growth. Lethal infection with Babesia bicornis have been linked to mortality and morbidity of rhinoceroses post-translocation in South Africa and Tanzania. Presence of such lethal Babesia or other piroplasms in the Kenyan rhinoceros meta-population has not been investigated. Such information is necessary in guiding health monitoring, translocation, diagnosis and veterinary care for the species. The aim of this study was to determine the species and genetic diversity of piroplasms in selected rhino sub-populations in Kenya. Blood samples were collected from 114 (82 black and 32 white) rhinoceroses during scheduled management activities by Kenya Wildlife Service between 2011 and 2012. The samples were collected from males and females of all age groups. Genomic DNA was extracted from whole blood using DNA extraction kit (DNeasy blood and Tissue Kit, QIAGEN) followed by a nested amplification of the 18S small subunit ribosomal RNA (18S ssrRNA) gene of Babesia and Theileria. The PCR products were analyzed by gel electrophoresis, and a subset of the positive secondary PCR products sequenced for both forward and reverse strands. Results showed that Theileria. bicornis was the only infecting species with a prevalence of 49.1%. No Babesia species were identified. White rhinoceroses (65.6%) were significantly infected compared to black rhinoceroses (42.7%, χ2 =0.028). More males were infected compared to females in both rhinoceros species but the difference was not statistically significant (χ2 = 0.353). There were variations in infection rates among the age categories with more sub adults infected compared to adults and juveniles but the difference was not significant (χ2 = 0.465). Results showed variations in infections among the sub-populations with Meru National Park having the highest infection rate (66.7%) and Solio Game Ranch the least (12.5%), but the differences were not statistically significant (χ2 = 0.140). Three new haplotypes of T. bicornis H1, H2, and H3 were identified in this study. H3 was the most predominant (66.7%) and was distributed in all the sampled sub-populations. H1was only found in Lake Nakuru National Park’s black rhinoceroses whereas H2 was identified in Lake Nakuru and Meru National Parks, and Ngulia Rhino Sanctuary. This study concludes that T. bicornis infects both black and white rhinoceroses and it is distributed in most of the conservational areas in Kenya. This being the first report of new T. bicornis haplotypes, the findings have important ecological and conservational implications, especially for future population management and translocation programs.