Field trial of the coproantigen-based diagnosis of Taenia solium taeniasis by enzyme-linked immunosorbent assay.

A microplate-type enzyme-linked immunosorbent assay for the detection of Taenia species antigen in human feces was tested in field studies undertaken in two Guatemalan communities. The test was based on immunoglobulin G antibodies from a rabbit hyperimmunized to Taenia solium proglottides. Comparison was made with microscopy and patient interviews as a means of diagnosis. The coproantigen test result was positive in 79 of the 1,582 fecal samples examined. Parasitologic confirmation was made in 55 of these cases. The coproantigen test was the most sensitive technique used, detecting 2.6 times as many confirmed cases of taeniasis as microscopy, which diagnosed 21 cases. Only one case was detected by interviewing. Microscopy revealed on false-negative coproantigen result. Mass treatment of the population did not result in the detection of any additional cases. Twelve coproantigen-positive results were categorized as unconfirmed and an additional 12 as putative false-positive results, giving an overall specificity of 99.2% for the coproantigen test. Of the 34 taeniid tapeworms identified to the species level, all were T. solium. The practicalities of the use of such a test in epidemiologic studies on human taeniasis are discussed.