Emergence of canine ocular Thelaziosis caused by Thelazia callipaeda in southern Switzerland.

In Europe, Thelazia callipaeda has been reported in Italy and France in the eyes of dogs, cats and foxes and, recently, also in humans. In southern Switzerland (Ticino), the first case of T. callipaeda in a dog was detected in 2000 and because of an increasing number of dog thelaziosis, a survey in veterinary practices was carried out. A total of 106 Thelazia-positive dogs from a retrospective analysis and from ongoing cases between 2005 and 2007 as well as five positive cats were reported. For a cross-sectional study, 529 randomly selected dogs (from six veterinary practices), to which anaesthesia was given for other medical reasons, were additionally checked for the presence of adult specimens of Thelazia in 2006: 28 dogs were found positive indicating an overall prevalence of 5.3%. Thelazia-infection was furthermore diagnosed in 7 of 126 foxes (5.6%) shot in Ticino in winter 2005-2006. Affected foxes, dogs and cats originated from the same regions up to 863m of altitude. The cats and 57.9% (55/95) of the infected dogs had never crossed the Swiss border. Collected nematodes were morphologically identified as T. callipaeda, and this diagnosis was confirmed by the analysis of a part of the sequence of the mitochondrial cytochrome c oxidase subunit 1 gene (cox1), revealing haplotype 1, the only one so far found in Europe. Animals harboured 1-23 eye worms. The most common symptoms were conjunctivitis and epiphora, while keratitis was present only in a low number of animals. Young and small sized dogs were significantly less involved than large animals and over 3 years of age. The results indicate that thelaziosis is endemic in that area.

[Is dirofilariasis in dogs spreading in south Switzerland?]. / Breitet sich in der Südschweiz die Dirofilariose beim Hund aus?

Microfilarial infections could be detected by the Difil Test in 11 (2.2%) of 479 blood samples of clinically asymptomatic dogs from the South of Switzerland. Dirofilaria repens and D. immitis were identified in 3 (0.6%) and 8 dogs (1.6%), respectively, by the acid phosphatase activity of the microfilariae. 10 dogs with microfilaremia had been abroad or a stay outside Switzerland could not be excluded. One dog diagnosed with D. immitis could have had acquired the infection in the canton Tessin according to information given by the owner. Dogs with microfilaremia are a potential source of infection for mosquitoes. An indigenous cycle of infection in the South of Switzerland is possible since the mean average temperature in summer is above 18 degrees C which is necessary for optimal parasite development in the vector. A strict control of imported dogs or animals exposed to the disease in endemic regions as well as the therapy of infected dogs in the South of Switzerland is advisable.