Trichinella nelsoni and Trichinella T8 mixed infection in a lion (Panthera leo) of the Kruger National Park (South Africa)

In South Africa, Trichinella sp. was first discovered in 1966 in the wildlife of the Kruger National Park (KNP). Since then, both Trichinella T8 and Trichinella nelsoni have been detected in the KNP, leading to a debate on the existence of a gene flow between the two taxa. In 2006-2008, four lions were killed in the Manyeleti Game Reserve, the Mthethomusha Nature Reserve, Numbi Gate, and Skukuza, which border the KNP. Larvae were isolated from muscles by artificial digestion. The molecular identification of single larva by multiplex PCR, followed by a specific PCR to distinguish between Trichinella T8 and Trichinella britovi, revealed Trichinella T8 in the lions from Manyeleti and Skukuza, a mixed infection with T. nelsoni and Trichinella T8 in the lion from Mthethomusha, and T. nelsoni in the lion from Numbi. No larva with a hybrid pattern between the two taxa was observed. No hybrid offspring resulted when crossing single males and females of T. nelsoni and Trichinella T8 in both directions, whereas hybrid offspring were obtained when crossing T. britovi and Trichinella T8 in both directions. This is the first report of a mixed infection with two Trichinella taxa in a host from the KNP, where both Trichinella T8 and T. nelsoni circulate among wildlife. Despite the sympatry status of these two taxa, field and laboratory data seem to exclude the possibility of gene flow, confirming their evolutive separation.