First Morphological and Molecular Description of Anatrichosoma sp. (Nematoda: Trichosomoididae) in the Nasal Cavities of a Sheep (Ovis aries) from Sardinia (Italy)

Cases of parasitic infection by Anatrichosoma spp. have occasionally been reported worldwide in a narrow range of host species, including humans. The species in which Anatrichosoma has been most commonly reported are nonhuman primates; among domestic animals, infections have only been reported in dogs and cats. Many aspects of the biological cycle and epidemiology of the parasite are still unknown. In the present study, we report the case of Anatrichosoma sp. infection in the nasal cavities of a sheep (Ovis aries) raised in Sardinia (Italy). After sagittal cutting of the sheep's head, 12 adult nematodes were recovered and collected: 10 specimens were subjected to morphological identification; 2 other specimens were processed for deoxyribonucleic acid (DNA) extraction and polymerase chain reaction targeting the small subunit (18s) ribosomal ribonucleic acid and the mitochondrial cytochrome c oxidase subunit I (COI mtDNA). Morphological identification classified all specimens as adult females belonging to the genus Anatrichosoma. Phylogenetic analysis placed the obtained sequences for both genes in the cluster of Anatrichosoma spp., with a higher interspecific variation observed at the COI mtDNA gene. The present unusual case of Anatrichosoma sp. infection in a sheep adds a new suitable host for this uncommon parasite, providing novel genetic data. This finding suggests that this rare parasite should be considered in human and animal mucosal parasitic infections and that molecular diagnosis should be performed in equivocal or doubtful cases.