Prevalence and molecular characterization of ascarid nematodes in cattle population from Malakand Division, Pakistan

Domestic livestock, particularly cattle, are crucial for food security, economic growth, and poverty reduction in Pakistan. Ascarid nematodes are parasitic worms that significantly impact cattle health, causing morbidity and mortality in these animals. However, information on the molecular characterization and prevalence of ascarid infections in the cattle population of Malakand Division is limited. A total of 230 stool samples were collected from cattle across five districts in Pakistan, specifically Swat, Bunir, Bajaur, Lower Dir, and Upper Dir, between October 2022 and September 2023. Routine fecal examinations were conducted using a combined approach of sedimentation, flotation, and centrifugation to effectively recover ascarid eggs. DNA was extracted from the eggs, and a partial sequence of the Cox-1 gene, a widely used molecular marker for nematode identification, was amplified via polymerase chain reaction (PCR). The PCR products were sequenced, and their sequences were compared with those in the NCBI GenBank database. A phylogenetic tree was constructed using the Neighbour-Joining method. The study identified two ascarid species: Toxocara vitulorum (31.30 %, 72/230) and Ascaris suum (21.30 %, 49/230), with A. suum being reported in Pakistan for the first time. The Cox-1 sequences involved 441 bp, with an isolate from Upper Dir showing 97.77 % similarity to T. vitulorum and a 435 bp isolate from Lower Dir being 99 % identical to A. suum. A high infection rate was observed in cattle grazing in hilly areas. This research highlights the prevalence and genetic diversity of ascarid nematodes in the local cattle population, confirming Cox-1 as a reliable genetic marker for identification. Further studies are essential to investigate transmission dynamics and develop effective control measures to ensure livestock health and improve the economic status of families in Malakand and across Pakistan.