Population genetic diversity of Fasciola spp. from Mpumalanga and KwaZulu-Natal provinces of South Africa.

Abstract

Fasciola hepatica and Fasciola gigantica have been identified as the species causing fascioliasis in ruminants and humans with intermediate species being reported as well. Studies have shown an economic loss in excess of three billion United States dollars annually in the livestock sector due to infection by fasciolids. With the increase in importance of the disease, taxonomic classification and genetic characterization of Fasciola spp. is essential. Molecular markers have shown utility in both identification of species and elucidating phylogenetic patterns. Recent studies have shown utility of mitochondrial markers in elucidating genetic relationships and diversity due to their high variability and rapid analysis. The current study was aimed at elucidating the evolutionary relationships and genetic diversity of Fasciola isolates from the KwaZulu-Natal (KZN) and Mpumalanga provinces in South Africa through analysis of the CO1 mitochondrial sequences. Fifty-five flukes were collected from abattoirs in the KZN and Mpumalanga provinces and DNA was extracted using the Phenol/Chloroform method. PCR amplification using the CO1 primers was performed with amplicons being sequenced at the Central Analytical Facilities of Stellenbosch University, South Africa. Resulting sequences were subjected to phylogenetic and diversity analysis. The study sequences were comparatively analysed with Genbank sequences from South Africa, Zimbabwe, Niger, Egypt and China; with Schistosoma japonicum as an outgroup. Phylogenetic analysis showed that F. hepatica was present in all localities studied whilst F. gigantica was identified only in the Mpumalanga province. A 100% prevalence of F. hepatica was observed in KwaZulu-Natal and the high-veld region of Mpumalanga (21 and 17 isolates respectively). Thirteen (76%) of the seventeen flukes collected from the Belfast region of Mpumalanga were identified as F. hepatica while four isolates were identified as F. gigantica. A total of twenty-two haplotypes were identified with eighteen novel haplotypes being unique to the isolates from South Africa. Two novel F. gigantica haplotypes were identified with none of the study isolates sharing haplotypes with the Genbank isolates from China, Niger and Zimbabwe. Sixteen novel F. hepatica haplotypes were identified and one haplotype was shared between the experimental flukes and the Genbank isolates from China and Niger. Within the study samples, a number of haplotypes were restricted to a few individuals with a haplotype diversity of 0.89 indicating high diversity. Results from this study adds new knowledge to the genetic diversity of Fasciola species and its distribution in the KwaZulu-Natal and Mpumalanga provinces of South Africa.