DIFFERENTIATION OF OESOPHAGOSTOMUM-BIFURCUM FROM NECATOR-AMERICANUS BY PCR USING GENETIC-MARKERS IN SPACER RIBOSOMAL DNA

Oesophagostomiasis in humans due to infection with Oesophagostomum bif urcum (nodular worm) is of major human health significance in northern Togo and Ghana where Necator americanus (human hookworm) also exists at high prevalence. However, very little is known about the transmissi on patterns of O. bifurcum, partly due to the difficulty in differenti ating O. bifurcum from N. americanus at some life-cycle stages using m orphological features. To overcome this limitation, a molecular approa ch utilizing genetic markers in the second internal transcribed spacer (ITS-2) of ribosomal (r) DNA was developed. The ITS-2 sequence of eac h species was determined, and specific oligonucleotide primers were de signed to the regions of greatest sequence difference between the spec ies. Utilizing these primers, rapid PCR assays were developed for the specific amplification of DNA of O. bifurcum or N. americanus, which h ave the potential to confirm the identity of eggs from faeces and larv ae from the intestine or environment. The application of species-speci fic PCR has important implications for studying the epidemiology and p opulation biology of O. bifurcum. (C) 1997 Academic Press Limited.