Abstract
BackgroundThelazia callipaeda eyeworms are transmitted by the non-biting insect vector Phortica variegata in Europe and infest the conjunctiva(s) of several mammalians, including dogs and humans. Infested hosts might remain asymptomatic or display clinical manifestations characterized by variable degrees of severity.MethodsFrom July to November 2011, nine dogs were detected with eyeworms at two veterinary clinics in Chaves and Bragança (North of Portugal). Nematodes collected from dogs were morphologically and molecularly characterized at species level.ResultsNematodes were identified as T. callipaeda. The number of worms collected from each dog ranged from three to 76 (average = 17.9 ± 26.8) and was not associated with the severity of clinical signs. Ocular discharge and conjunctivitis were observed in all dogs and ocular pruritus occurred in six of them. Polymerase chain reaction and sequencing of a portion of target cytochrome c oxidase subunit 1 gene further identified all nematodes as haplotype 1.ConclusionsThis is the first report of T. callipaeda and associated ocular disease in dogs from Portugal, suggesting that thelaziosis should be included in the differential diagnosis of canine ocular affections. The risk of the infestation spreading from Spain and France to Portugal, through domestic dogs or wild mammals, is realistic.
Highlights
Thelazia callipaeda eyeworms are transmitted by the non-biting insect vector Phortica variegata in Europe and infest the conjunctiva(s) of several mammalians, including dogs and humans
Polymerase chain reaction and sequencing of a portion of target cytochrome c oxidase subunit 1 gene further identified all nematodes as haplotype 1. This is the first report of T. callipaeda and associated ocular disease in dogs from Portugal, suggesting that thelaziosis should be included in the differential diagnosis of canine ocular affections
While the occurrence of T. californiensis is limited to western areas of the United States of America [2], T. callipaeda is widely distributed in far eastern countries and throughout Europe
Summary
Thelazia callipaeda eyeworms are transmitted by the non-biting insect vector Phortica variegata in Europe and infest the conjunctiva(s) of several mammalians, including dogs and humans. While the occurrence of T. californiensis is limited to western areas of the United States of America [2], T. callipaeda is widely distributed in far eastern countries and throughout Europe. These nematodes are transmitted by non-biting insect vectors and can be found in the conjunctiva(s) of vertebrate hosts [1]. A fruitfly species of the subfamily Steganinae, i.e. Phortica variegata, is the recognized intermediate host of T. callipaeda in Europe [3,4]. The evidence of one unique haplotype circulating in Europe, irrespective of the several host species from which the nematodes had been collected, led to the hypothesis that the populations of T. callipaeda in Europe are strictly associated with the species of arthropod vector [15]
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