PCR assay for the specific amplification of Oesophagostomum bifurcum DNA from human faeces

Oesophagostomiasis in humans due to infection with Oesophagostomum bifurcum (nodule worm) is of major human health significance in northern Togo and Ghana where the human hookworm, Necator americanus, also exists at high prevalence. Accurate diagnosis of O. bifurcum infection in humans is central to studying the epidemiology and controlling the parasite. To overcome limitations of current copro-diagnostic methods, we have developed an alternative, molecular approach. Utilising genetic markers in the second internal transcribed spacer (ITS-2) of ribosomal DNA, we have established a two-step, semi-nested PCR method for the specific amplification of minute amounts (fg) of O. bifurcum DNA from human faecal samples. Using a panel of 155 well-defined faecal and DNA samples, the assay achieved a sensitivity of 94.6% and a specificity of 100%. This PCR assay will be useful for the diagnosis of O. bifurcum infection and as a molecular tool for elucidating the epidemiology of human oesophagostomiasis.