Screening for infection of Trichinella in red fox (Vulpes vulpes) in Denmark

A total of 6141 foxes (Vulpes vulpes) were examined for infection with Tric hinella. The foxes were killed in Denmark during the hunting season 1995-19 96 and 1997-1998; 3133 and 3008, respectively, Foxes included in the invest igation came from throughout the country with the exception of the island o f Bornholm. The right foreleg from each fox was submitted for investigation . The legs were stored at -20 degrees C for 3-10 months prior to examinatio n. Following thawing, muscle tissue (10 g) from each leg was examined by tr ichinoscopy and by a pepsin-HCl digestion technique. In 1995-1996, three foxes were found positive corresponding to a prevalence of 0.001. Each of the infected foxes harboured an extremely low infection, i.e, about one larva per 10 g muscle tissue. It was not possible to obtain sufficient larval material for species identification, All three foxes wer e shot in the vicinity of a small village in the north-western part of Denm ark. In 1997-1998 no Trichinella cases were found. The results, compared with previous studies, indicate that the prevalence o f infection of Trichinella sp. among wild living foxes in Denmark is very l ow. This is further supported by the fact, that no infection of Trichinella sp. has been found in slaughtered pigs in Denmark for more than 65 years, which suggests that the infection pressure is very low, Considering the fac ts above we conclude that the risk of Trichinella infections is negligible in intensive indoor pig production units in Denmark whereas high local prev alence of Trichinella infections in the wildlife might constitute a serious risk for the expanding outdoor pig production. (C) 2000 Elsevier Science B .V. All rights reserved.