Strongyloides cf fuelleborni was found to be distributed homogeneously with respect to space and time in a semi-nomadic community in Papua New Guinean rainforest. The parasite predominantly infects children, reaching 60% prevalence in the first year of life and peaking around 80% at five years of age. Egg loads follow a similar pattern but peak earlier (at 20 months) and fall off more sharply. The few infected adults have very light infections as measured by egg count. In the first few months of life, incidence was estimated as 50% per month. Following treatment, incidence in older children was reduced to around 9% per month. By comparison, hookworm infection (probably all Necator americanus) has a much lower incidence in early life, and this increases with age. The high incidence of Strongyloides in early life is not explained by prenatal infection or by contamination from maternal faeces.