Hydatid disease in New Zealand: an epidemiological study of transmission among Maoris.

An epidemiological study was designed to determine the factors placing the Maori people of New Zealand at an unusually high risk of infection with Echinococcus granulosus. Using stepwise multiple regression techniques, it was shown that the most important determinant of the incidence rate of human hydatid disease was the proportion of Maoris in the local population. It was found that the Maori system of land tenure, based on the Maori land laws led to the formation of many small fragmented properties under multiple ownership, decreasing the incentive of individual Maori farmers to improve their farming methods. In addition, long-standing behavioral patterns, such as an easy familiarity with working dogs and the feeding of dogs on raw offal, were practices that changed slowly, thus contributing to the maintenance of high E. granulosus prevalence in dogs owned by Maoris. Those cultural and behavioral factors, together with poor dog control, exposed all members of the rural Maori community to an increased risk of infection with E. granulosus, with the result that the incidence rate of hydatid disease for all age-groups and for both sexes was strikingly higher in Maoris than in non-Maoris.