Trichinella species are widely distributed on all continents with the exception of Antarctica, although the full spectrum of Trichinella species found in sub-Saharan African countries, and their hosts, has not been fully documented. This study was conducted to determine the prevalence of Trichinella in wildlife from the Greater Kruger National Park (GKNP) and adjacent areas located in the Limpopo and Mpumalanga provinces of South Africa, and to identify the species and/or genotypes of Trichinella larvae isolated from muscle tissues, using molecular techniques. A review of Trichinella spp. and their wildlife hosts reported during 1964-2011 was also conducted and the results were compared with our current study. Ninety samples representing 15 mammalian, two bird and three reptile species were screened for Trichinella infection during 2012-2016, using artificial digestion. Isolates detected were identified using a multiplex polymerase chain reaction (PCR) amplification of the internal transcriber spacers ITS1 and ITS2, and expansion segment V (ESV) regions of ribosomal DNA, followed by molecular analysis of the sequences. Twenty samples from seven wildlife species were positive for Trichinella spp. larvae, with an overall prevalence of 21.1% (20/90). The prevalence was higher in carnivores (18.9%, 18/90) than in omnivores (2.2%, 2/90). Analysis of sequences showed that eight of the isolates - two from spotted hyaena (Crocuta crocuta) (2/8), three from lion (Panthera leo) (3/13), one from leopard (Panthera pardus) (1/6), one from small spotted genet (Genetta genetta) (1/2) and one Nile monitor lizard (Varanus niloticus) (1/2) - conformed to Trichinella zimbabwensis. One isolate from a hyaena was grouped under the encapsulated species clade comprising T. nelsoni and genotype Trichinella T8 reported to be present in South Africa. This is the first report confirming natural infection by T. zimbabwensis in hyaena, leopard, genet and Nile monitor lizard, adding to the body of knowledge on the epidemiology of Trichinella infections in the Greater Kruger National Park of South Africa. Ten Trichinella-like larval isolates recovered after digestion from four wildlife species in this study (2012-2016) revealed inconclusive results due to DNA degradation resulting from poor storage or too few larvae for analysis, in comparison to 20 unidentified isolates from five wildlife species during the 1964-2011 period.
At least three Trichinella species, namely Trichinella nelsoni, Trichinella britovi and Trichinella zimbabwensis, and one genotype (Trichinella T8), have been isolated from sylvatic carnivores on the African continent. With the exception of T. britovi, the other species are known to circulate in wildlife of the Kruger National Park (KNP), South Africa, and KNP neighbouring game reserves (collectively known as the greater KNP area). Lions (Panthera leo) and spotted hyenas (Crocuta crocuta) appear to be the most important reservoirs of T. nelsoni and Trichinella T8 in the KNP and surrounding areas. Interspecies predation between lions and hyenas has been implicated as a primary mode of maintaining the life cycles of these two Trichinella species. This is the first report of a mixed natural infection of T. nelsoni and Trichinella T8 in a leopard (Panthera pardus) from South Africa. Trichinella muscle larvae were identified to species level by multiplex polymerase chain reaction (PCR). Probable sources of infection, based on the known dietary preference and prey species' range of leopards, are also discussed. The described occurrence of Trichinella species in a leopard from the greater KNP area raises the question of possible sources of infection for this predator species.
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