High prevalence of ascariasis on two coral atolls in the Solomon Islands

There is a deficiency in up-to-date soil-transmitted helminth (STH) prevalence data for many regions, including Oceania. This study investigated the prevalence of STH in two closely associated coral atoll communities in East Kwaio, Solomon Islands, reflective of many similar island communities throughout the Oceania region.

An STH survey, using the Kato-Katz technique, was conducted on human subjects living on two coral atolls in the Eastern Solomon Islands. The capacity of Ascaris lumbricoides eggs to float in seawater was also evaluated by passive flotation.

Of 583 people tested on both islands, 311 (53.3%) harboured A. lumbricoides, with 51.7% (n=161) of those having moderate to high-intensity infections. Hookworm was detected in 139 (23.7%) participants and Trichuris trichiura infection in 18 (3.1%). A. lumbricoides eggs were not found to float in seawater.

The high prevalence and intensity of ascariasis on these two atolls was contrasted with previously described STH studies in mainland East Kwaio villages, where hookworm predominates and ascariasis is almost absent. This led to a preliminary consideration that transmission of A. lumbricoides on densely populated coral atolls might be associated with defecation into the sea and transmission in seawater, although further work is required to investigate this hypothesis.