Prevalence Rate and Molecular Characteristics of Oestrus ovis L. (Diptera, Oestridae) in Sheep and Goats from Riyadh, Saudi Arabia

SIMPLE SUMMARY: In the current study, we investigated the prevalence rate of Oestrus ovis (O. ovis) larvae in heads of sheep and goats obtained from abattoirs in Riyadh, Saudi Arabia. It was found that season did not have any significant effect on the characteristics of the larvae that affect sheep, except for the length of larva, for which those collected in spring differed from those collected in winter and autumn. In goats, the L3 instar number was significantly higher during summer. Oestrus ovis larvae were detected in sheep and goats by molecular analysis and they were most closely related to O. ovis larvae recovered from GenBank. ABSTRACT: Heads of sheep (n = 600) and goats (n = 800) slaughtered at Al-Aziziah Abattoir in Riyadh, Saudi Arabia, were inspected for the presence of O. ovis larvae (L). Heads were split along the longitudinal axes, and larvae (L1, L2, and L3) were gathered. The infestation rate was significantly higher in goats (44.5%; 356/800) than that in sheep (22.3%; 134/600). Out of the 151 collected larvae from sheep, 0% were L1, 1.3% were L2, and 98.7% were L3. Out of the total of 468 larvae from goats, 0% were L1, 1.2% were L2, and 98.8% were L3. The infestation rate was significantly higher in males than that in females. Myiasis-causing larvae collected from Riyadh, Saudi Arabia, were authenticated as O. ovis, according to morphological characteristics. Polymerase chain reaction (PCR) amplification of a partial fragment (600 bp) of the mitochondrial cytochrome c oxidase subunit I (mtCOI) gene further confirmed the species. Phylogenetic analysis based on the partial mtCOI gene sequence demonstrated that 23 unique sequences showed high similarity based on nucleotide pairs of O. ovis accessions retrieved from GenBank.