Eucoleus garfiai (Gállego et Mas-Coma, 1975) (Nematoda: Capillariidae) infection in wild boars (Sus scrofa leucomystax) from the Amakusa Islands, Japan.

We examined lingual tissues of Japanese wild boars (Sus scrofa leucomystax) captured in the Amakusa Islands off the coast of Kumamoto Prefecture. One hundred and forty wild boars were caught in 11 different locations in Kamishima (n = 36) and Shimoshima (n = 104) in the Amakusa Islands, Japan between January 2016 and April 2018. Lingual tissues were subjected to histological examinations, where helminths and their eggs were observed in the epithelium of 51 samples (36.4%). No significant differences in prevalence were observed according to maturity, sex or capture location. Lingual tissues positive for helminth infection were randomly selected and intact male and female worms were collected for morphological measurements. Based on the host species, site of infection, and morphological details, we identified the parasite as Eucoleus garfiai (Gállego et Mas-Coma, 1975) Moravec, 1982 (syn. Capillaria garfiai). This is the first report from outside Europe of E. garfiai infection in wild boars. Phylogenetic analysis of the parasite using the 18S ribosomal RNA gene sequence confirmed that the parasite grouped with other Eucoleus species, providing additional nucleotide sequence for this genus. Since wild boar populations are widely distributed in Japan, continuing surveys on the epidemiology of the parasite and identifying possible intermediate host candidates are crucial for elucidating the transmission route of the parasite.