Strongyloides cf. fuelleborni and hookworm in Papua New Guinea: patterns of infection within the community

Abstract

The results of quantitative stool examinations from a large number of rural Papua New Guineans permitted the establishment of age-prevalence and age-intensity profiles and frequency distributions of both Strongyloides cf. fuelleborni and hookworm. Strongyloides exhibited a unique age-prevalence profile which originated at about 40% in the youngest age group, rose to a maximum in those 4-5 years old, and then declined. The intensity of infection reached its peak in 12 month olds before declining. The frequency distribution of Strongyloides egg counts was markedly over-dispersed: k values were below 0.1 for most age groups. Both prevalence and intensity of infection curves for hookworm followed similar patterns, which were typical for the parasite, rising to a maximum at about age 9 years, and then forming a plateau. The distribution of hookworm egg counts was less over-dispersed than that of Strongyloides, the k values rising until about 10 years of age and then remaining stable with a value of about 0.7. With both parasites there was little difference in prevalence or intensity of infection between the sexes, although adult males tended to have higher levels for both quantities.