Thelazia callipaeda, an Endemic Parasite of Red Foxes (Vulpes vulpes) in Western Romania

Thelazia callipaeda (Spirurida, Thelaziidae) is a vector-borne zoonotic nematode parasite of the conjunctival sac of a large spectrum of hosts, currently having an expanding distribution range throughout Europe. In Romania, the parasite has a relatively large distribution range and host spectrum. However, the presence of T. callipaeda in red foxes ( Vulpes vulpes) has not yet been confirmed. The aim of the present study was to assess the prevalence and geographical distribution of T. callipaeda in red foxes from Romania. A total of 514 animals originating from 10 counties of western Romania were evaluated for the presence of T. callipaeda. Overall, 151 red foxes (29.38%) were positive. No significant differences were noticed between sex and age groups of positive foxes. In total, 3,350 adult nematodes were recovered. The intensity of infection had a mean value of 23.2, while the sex ratio was 2.2:1 in favor of females. In 91 foxes, both eyes were affected, while 60 harbored unilateral infection. Sequence analysis of the cox 1 gene of one nematode from each positive fox ( n=151) revealed the exclusive presence of haplotype h1. We report a relatively high prevalence and distribution range of T. callipaeda infection in red foxes in Romania, highlighting their potential role as a wildlife reservoir.