Clinical features of experimental trichinellosis in the raccoon dog (Nyctereutes procyonoides)

Three groups of six raccoon dogs (Nyctereutes procyonoides) were provided f or the experiment: the first group was infected with pig-origin Trichinella spiralis, the second with raccoon dog-origin Trichinella nativa, and the t hird served as controls. Infection dose for both parasite species was 1000 larvae/kg of body weight, which led to intense final infection. Clinical si gns, haematology and serum biochemistry with repeated blood samples were mo nitored up to 12 weeks post-infection. The most significant findings were a short-term eosinophilia in peripheral blood from the end of the first week post-infection until the end of the third week, loss of weight, and mild a naemia. In the early phase of the infection. the animals had gastrointestin al signs, loss of appetite and diarrhoea. No specific differences in clinic al findings could be noticed between the groups infected with T. nativa and T. spiralis. In contrast to the symptoms reported in human outbreaks, feve r was not observed in any of the infected animals and serum levels of muscl e-specific enzymes did not change. No acute-phase response was observed in the enteral or parental phase of the infection. These findings indicate tha t because Trichinella spp. are very well adapted to the raccoon dog, it thu s, could serve as the most crucial reservoir animal for sylvatic trichinell osis in Finland. (C) 2000 Elsevier Science B.V. All rights reserved.