In order to estimate the proportion of hookworm infections represented by Necator americanus and
Ancylostoma duodenale, the 2 major species of human hookworms in Nigeria, stool samples from 1253
hookworm-positive schoolchildren were cultured to the third-stage (L3), filariform larvae, using the
Harada-Mori test-tube method. N. americanus larvae were recovered from a total of 1177 (93.9%)
coprocultures while A. duodenale larvae were recovered from a total of 274 (21.9%) stool cultures.
58.2% of the hookworm infections were due solely to N. americanus, 6.1% solely to A. duodenale and
25.8% were mixed infections with both species. In all mixed infections, much higher number of N.
americanus larvae were recorded compared with those of A. duodenale.