Global distribution of human hookworm species and differences in their morbidity effects: a systematic review.

The global distribution and morbidity effects for each specific hookworm species is unknown, which prevents implementation of the optimum intervention for local hookworm control. We did two systematic reviews of studies on the proportion of hookworm isolates of each species and genus by region of the world and associations between hookworm species-specific infections and morbidity outcomes, particularly severe anaemia. Necator americanus and Ancylostoma spp were present in all regions of the world, although at different ratios. No clear evidence was found for the differential morbidity effects of different hookworm species. Diagnostic methods that differentiate between hookworm species, including molecular methods, need to be developed for widespread use in control programmes to elucidate key features of hookworm epidemiology and control.