RESUMEN
Infection by the nematode Oesophagostomum bifurcum is focally distributed in Africa and causes a syndrome of abdominal pain, obstruction, or abdominal mass because of its predilection for invasion of colonic mucosa. To determine the reliability of ultrasound for the detection of colon pathology induced by this parasite, three studies to assess the intraobserver and interobserver variation of the technique were performed. In an area of northern Ghana endemic for O. bifurcum, 181 people from a low-prevalence village and 62 people from a high-prevalence village were examined twice by the same observer, and 111 people were independently examined by two observers in a moderately endemic village. The kappa statistics for the prevalence observations in the three studies were 0.82, 0.87, and 0.81, respectively, and kappa values for the intensity observations were 0.66, 0.63, and 0.71, respectively. The upper 95% confidence intervals of the average absolute difference in nodule size measurements in Study 1 and Study 3 were 3.6 and 4.5 mm, respectively. Therefore, ultrasound is useful in the diagnosis and management of O. bifurcum colon infection.