Polyparasitism on the Kenya coast. 2. Spatial heterogeneity in parasite distributions.

In a parasitological survey of people living in 20 clusters of homes within 50 km of Kilifi, Coast Province, Kenya, internally age-standardized prevalences showed considerable variation. While this was correlated, in part, with the steep gradients of environmental variables related to distance from the coast, considerable residual variation remained. Indeed, isopleths for parasite prevalence frequently transected those for environmental parameters. It is concluded that broad environmental parameters are limited in their predictive value for determining parasite presence or prevalence; a study of the causes of major differences between villages in the same environment might indicate relatively simple control measures.