Thelazia callipaeda in wild carnivores from Romania: new host and geographical records

Abstract

BackgroundThelazia callipaeda is a vector-borne zoonotic nematode parasitizing the conjunctival sac of domestic and wild carnivores, rabbits and humans, with a vast distribution in Asia and the former Soviet Union. In Europe, the nematode has an emerging trend, being reported in Italy, France, Switzerland, Germany, Spain, Portugal, Bosnia and Herzegovina, Croatia, Romania, Greece and Serbia, with human cases known in Italy, France, Spain, Serbia and Croatia. In Romania, the infection was so far reported only in dogs, whereas there are no reports in wildlife despite the large numbers of wild carnivores in the country. The aim of this study was to evaluate the role of wild carnivores in the natural cycle of T. callipaeda in Romania.MethodsBetween 2014 and 2016, 89 wild carnivores (64 golden jackals, Canis aureus, 13 grey wolves, Canis lupus, nine wildcats, Felis silvestris and three Eurasian lynxes, Lynx lynx) have been examined. During the necropsy, both eyes of all the examined animals have been thoroughly inspected for the presence of parasites. If present, all nematodes were collected in absolute ethanol (for molecular analysis of the partial cox1 gene) or in 4 % formalin (for morphological identification).ResultsIn total, three animals were found to be infected with T. callipaeda: a grey wolf, a golden jackal and a wildcat. The BLAST analysis of all the sequences showed a 100 % similarity to T. callipaeda haplotype h1. To the best of our knowledge, this study represents the first report of T. callipaeda in golden jackals, and the first study on T. callipaeda in wildlife from Romania.ConclusionOur data broaden the host spectrum and geographical distribution of T. callipaeda, highlighting the role of wild carnivores as natural reservoirs for the infection and confirming the ongoing expanding trend of this zoonotic nematode in Europe.

Population structure analysis of the neglected parasite Thelazia callipaeda revealed high genetic diversity in Eastern Asia isolates

“…The spirurid nematode Thelazia callipaeda (Spirurida: Thelaziidae) is the major etiological agent of ocular thelaziosis [ 1 ]. This worm can parasitize the conjunctival sac of domestic and wild carnivores and humans, causing conjunctivitis, lacrimation and itchiness, and even blindness [ 2 , 3 ]. The parasite is transmitted by a drosophilid insect of the genus Phortica (Diptera, Drosophilidae), that feeds on the lachrymal secretions of mammals [ 4 , 5 ].…”

Competence of Phortica variegata from the United States as an Intermediate Host of the Thelazia callipaeda Eyeworm

“…Based on their relationships to known Thelazia hosts in Europe, 2 potential hosts in New York State include coyotes, red fox, gray fox, black bear, raccoon, mink, least weasel, striped skunk, cottontail rabbit, and snowshoe hare. 16 Therefore, the role of wildlife (e.g., foxes, jackal, hares, and wolves) 2,17,18 as reservoirs of T. callipaeda should be assessed, considering that the infection most likely establishes in wildlife before spreading to dogs and other domestic animals. 2 In Europe, eyeworm infection is often reported in foxes, most likely because of the more frequent exposure of wild carnivores to Phortica spp.…”

The first feline and new canine cases of Thelazia callipaeda (Spirurida: Thelaziidae) infection in Hungary

“…The occurrence of this spirurid nematode species has also been reported in Eastern Europe. The adult worms have been found in one or both eyes of dogs, cats, foxes and/or humans in Croatia [ 7 , 21 ], Serbia [ 8 , 22 , 35 ], Romania [ 23 , 24 ], Bosnia and Herzegovina [ 21 ], Bulgaria [ 25 ] and Slovakia [ 26 , 27 ]. Before this study, only a single canine ocular thelaziosis was reported in Hungary [ 28 ].…”

“…Considering the first cases of canine thelaziosis found close to the southern and northern borders of Hungary, we assume that T. callipaeda may have been introduced recently or arrived in the country several years ago by infected host(s) from neighbouring countries where the occurrence of this nematode species has been reported [ 21 , 22 , 26 , 27 ]. Thelazia callipaeda seems more likely to be transmitted to Hungary by wild carnivores, which play an important role in the sylvatic cycle of this eyeworm species [ 3 , 21 , 24 , 37 ]. It has been reported that the specimens of this nematode were found in the eyes of red foxes in the northern regions of Balkans [ 21 ] and in the southern part of Slovakia close to the Hungarian border [ 27 ] (Fig.…”