THE PREVALENCE AND EPIDEMIOLOGY OF ANOPLOCEPHALA-PERFOLIATA INFECTIONIN NORWAY

The caecum and the adjacent 30 cm lengths of ileum and large colon of 201 horses from two different regions of Norway (Ostlandet and Trondel ag) were examined for the presence of Anoplocephala perfoliata. In all , 20% of the horses were infested with the cestode (27% in Ostlandet a nd 7% in Trondelag). Tile mean number of worms in infected horses from the two regions was 18 and 6, respectively. Information was obtained on the age, sex, breed, type of pasture and anthelmintic treatment aft er the grazing season for 183 of the 20 horses. The degree of infestat ion with A. perfoliata was not influenced by age, breed or sex. The od ds ratio (confidence limits) for using permanent pastures that had bee n grazed by horses for at least the 5 last years in succession was 8.8 (3.2-24.4). There was a significantly higher prevalence of A. perfoli ata infestation in Ostlandet (odds ratio 3.1 (1.1-9.1). The relatively low prevalence of A. perfoliata infestation in Norwegian horses compa red to the reported prevalences in other countries and the differences in the prevalence between Ostlandet and Trondelag are discussed. Cros s pathological examination identified lesions such as mucosal thickeni ng, hyperaemia and/or erosions. These lesions were found in all of the infected horses, compared with only 5% of the non-infected horses. Ex amination of faecal samples from 26 of the infected horses detected ce stode eggs in only three cases. It was concluded that faecal examinati on is an inadequate method for the diagnosis of A. perfoliata infestat ion.