Genetic diversity and population structure of Fasciola gigantica isolated from cattle in Malawi

Fasciola gigantica is an important trematode that affects the health of animals and humans in tropical and subtropical countries, including Malawi. Information on the genetic diversity and population structure of F. gigantica is important to understanding the parasite`s transmission patterns/ and in monitoring the development of resistance to commonly used anthelmintic agents. This study aimed to analyze the genetic diversity and population structure of Fasciola species collected from cattle at slaughter slabs and abattoirs in selected districts of Malawi. A total of 27 adult liver flukes were collected from cattle at slaughter slabs and abattoirs in the northern region (n = 12), central region (n = 5), and southern region (n = 10). The mitochondrial cytochrome c oxidase I (COI) gene and nicotinamide adenine dinucleotide dehydrogenase 1 (ND1) gene were amplified and the amplicons were sequenced for all samples. The sequences obtained were used to investigate genetic diversity through median-joining networks and phylogenetic analysis. Tajima's D test and Fu's Fs statistics were used to determine the population structure. Based on the analyzed COI and ND1 sequences, all samples were identified as F. gigantica. Single nucleotide polymorphisms (SNPs) were identified at 18 and 17 positions for COI and ND1 genes, resulting in 10 and 5 haplotypes, respectively. The haplotype diversities were 0.867 and 0.479 for COI and ND1 gene sequences, respectively. The population genetic structure indices showed a population that has undergone a recent expansion. This study provides baseline epidemiological data on the genetic diversity and population structure of F. gigantica in Malawi; which is important for its control.