Molecular Studies of Gastrointestinal Strongyle Nematodes in Migratory, Resident, and Sedentary Plains Zebras (Equus quagga) in Kenya

Abstract

The molecular identity of gastrointestinal (GI) strongyle larvae recovered from faecal cultures from plains zebras in Kenya was determined using molecular tools. Internal transcribed spacer (ITS) ribosomal DNA (rDNA) extracted from the larvae were amplified using Polymerase Chain Reaction (PCR), sequenced for identification, and compared to sequences in the GenBank to determine their phylogeny. Sixteen sequences were obtained and identified as Cyathostomum montgomeryi, Cylicostephanus minutus, Poteriostomum imparidentatum, Triodontophorus nipponicus and Strongylus vulgaris. The genetic identity of P. imparidentatum, T. nipponicus and S. vulgaris from plains zebras in Kenya are reported for the first time in this study. The 16 sequences clustered into 5 clades according to the 5 genera of nematodes identified. The clade having T. nipponicus was placed as a sister to the Cyathostominae but was very distinct from the clade having S. vulgaris. The close clustering of T. nipponicus to the Cyathostominae supports previous suggestions that it belongs to this subfamily rather than Strongylinae. Five sequences of C. montgomeryi clustered closely with four sequences of C. montgomeryi in the GenBank isolated from zebras in Kenya. The other five sequences were evolutionary distinct. Similarly, two of the Cy. minutus sequences clustered with Cy. minutus sequences from zebras in Kenya, while the other one, was distinct. These results suggest intra-species genetic polymorphism among the C. montgomeryi and Cy. minutus isolates. The Poteriostomum imparidentatum, T. nipponicus, and S. vulgaris sequences were distinct from sequences found in the GenBank. This study contributes to the scanty but growing literature on equine strongyle genetics in zebras.

Keywords

• molecular identity
• phylogeny
• strongyles
• plains zebras