Molecular identification of different Trichostrongylus species infecting sheep and goats from Dakahlia governorate, Egypt.

Nematodes of genus Trichostrongylus can cause remarkable economic losses in the small ruminant`s industry and some species have a zoonotic potential. Since the most common source for human infection is the infected animals, accurate identification of different Trichostrongylus species in animals would reflect the species that can infect humans from the same area. The objective of the present study is to identify common Trichostrongylus species infecting small ruminants in Dakahlia governorate, Egypt using molecular-based techniques. Fecal samples from 340 sheep and 115 goats from rural areas in 3 cities of Dakahlia governorate and 2 cities at its borders were collected, and the strongyle-type eggs were detected in 33.2% and 14.7% of sheep and goats, respectively. PCR amplification of the internal transcribed spacer of the ribosomal DNA (ITS2 rDNA) for 3 Trichostrongylus spp.; T. axei, T. colubriformis and T. vitrinus was conducted for eggs harvested from 25 sheep and 16 goat samples. Two species were detected; T. axei (in 16 sheep and 14 goats) and T. colubriformis (in 2 sheep but no goats). This is the first report of T. colubriformis in sheep from Dakahlia governorate, where this species was reported earlier from humans. No T. vitrinus was detected in any tested sample of sheep or goats. Purified PCR products of T. axei isolates were successfully sequenced and revealed 3 haplotypes; 2 from sheep and 1 from goats, and the isolates are related genetically to T. axei isolates from camels in Egypt. Phylogenetic analysis of the Genbank-retrieved ITS2-amplified T. axei isolates worldwide suggested the existence of genetic variants. Earlier reports on the identified Trichostrongylus spp. in different animals from Egypt as well as African and Arabian countries are tabulated. © Indian Society for Parasitology 2020.