Resolution of canine ocular thelaziosis in avermectin-sensitive Border Collies from Spain

Ocular thelaziosis by Thelazia callipaeda is an emerging disease that affects primarily dogs, but also cats, foxes and other wild carnivores, as well as humans. Three clinical cases of unilateral conjunctivitis caused by Thelazia nematodes were detected in Border Collie, a dog breed intolerant to the macrocyclic lactones. Animals came from southwestern Spain, on the border with Portugal. Eight worms were collected and identified molecularly as T. callipaeda by amplification and sequencing of partial cytochrome c oxidase subunit 1 gene. Oral treatment with mebendazole 20 mg/kg (Telmin®) was effective in curing the infection.