Strongyloides and hookworm in Papua New Guinea: longitudinal studies on treated and untreated children

Helminth egg counts were made on 86 treated and 38 untreated children in an isolated Papua New Guinea community before treatment and on nine subsequent occasions over an 18-month period. No predisposition could be detected to heavy or light infection with hookworm, either in the rate of reinfection or in the maximum post-treatment egg counts. Indications of predisposition in Strongyloides cf. fuelleborni were not statistically significant. In untreated children, sequential age-standardized hook-worm egg counts remained significantly correlated with each other at time lags up to nine months, but those for Strongyloides showed good correlation if made up to 14 months apart. Possible explanations include a surprising longevity of Strongyloides worms or unexpected external auto-infection.