Thelazia callipaeda (Spirurida, Thelaziidae) in wild animals: report of new host species and ecological implications.

Thelazia callipaeda infects the eyes of carnivores and humans in Far Eastern Asiatic and
European countries. Studies have demonstrated the occurrence of T. callipaeda in foxes
from areas where canine thelaziosis is endemic. However, there is little information on the
role of wild carnivores as hosts of this nematode. From May 2003 to May 2009, a total of
130 carcasses of red foxes (Vulpes vulpes; n = 75), wolves (Canis lupus; n = 2), beech martens
(Martes foina; n = 22), brown hares (Lepus europaeus; n = 13), Eurasian badgers (Meles
meles; n = 10), and wild cats (Felis silvestris; n = 8) were examined in an area of southern
Italy where canine thelaziosis is highly prevalent. At necropsy, animals were examined
and nematodes were collected from the conjunctival sacs of both eyes. All nematodes
were morphologically identified and at least five specimens from each of the five host
species were molecularly processed by PCR amplification and sequencing of a partial
mitochondrial cytochrome c oxidase subunit 1 gene (cox1). Five out of the six wild animal
species examined were found to be infected with eyeworms. The overall infection rate,
excluding the Eurasian badgers that were all negative, was 39.1%. All the 189 adult
nematodes collected (intensity of infection = 4 2.2) were morphologically identified as T.
callipaeda. The molecular analysis confirmed that the only haplotype of T. callipaeda circulating
in Europe (i.e., haplotype 1) is present in that area. The competence of red foxes, wolves, beech
martens, brown hares, and wild cats as definitive hosts for T. callipaeda is discussed in
relationship to their ecology and their likely exposure to the vector Phortica variegata in the
study area. The role the wild fauna plays in maintaining and spreading eyeworm infection in
humans and domestic animals is also discussed.