Liver fluke (Fasciola hepatica) in slaughtered sheep and cattle in New Zealand, 1984-85

A total of 17175 lambs livers and 9322 sheep livers randomly selected from animals slaughtered at export meatworks in 1984 were examined for liver fluke infection. Futher sheep livers from some regions were examined in 1985. The origins of the animals examined were recorded and used to estimate regional prevalences of infection. Infection in lambs was first detected in February and the prevalence increased after then; the mean prevalence in July was 2.7% in the North Island and 2.0% in the South Island . In adult sheep in 1984, regional prevalences in the North Island ranged up to 16.9% (>10% in South Auckland, East Coast, Hawkes Bay and Taranaki) and in the South Island up to 29.4% in Westland (18% in Nelson). The overall prevalence in the North Island was 7.5% and in the South Island 1.1%, about double that recorded in 1969. Data for 1985 were incomplete but prevalences tended to be higher than in 1984. From April 1984 to August 1985 the origins of all lines of cattle with fluke-affected livers were recorded in all abattoirs and export meatworks. During 1985, 16 147 infected lines were traced to all countries in the North Island, with over 60% from the Whangarei, Hamilton, Taumarunui, Gisborne and Hastings areas. In the South Island , over 90% of 1585 infected lines originated from Westland, Waimea, Grey, Inangahua and Buller Counties.