Coproantigen detection for immunodiagnosis of echinococcosis and taeniasis in dogs and humans

Abstract

SUMMARYThree ELISA assays, based on hyperimmune rabbit serum raised against adult cestode somatic antigen, were applied in this study for the detection ofTaenia- andEchinococcus-specific antigens in host faeces. The first assay, using an antiserum againstTaenia pisiformisantigen extract, was used in a time-course ofT. pisiformisexperimental infection in dogs. The assay was shown to be considerably more sensitive than microscopical detection of eggs in faeces. Antigen was present in faeces before patency and antigen levels were independent ofT. pisiformisegg output. The second assay, involving a test for human taeniasis based on antibodies againstT. solium, was applied in two field studies carried out in China and Guatemala. The test was highly specific, no false positive reactions occurred with human faecal samples and the test was capable of diagnosing individuals who would not have been detected by coproscopy or treatment to recover the tapeworm. A third assay was designed forE. granulosusand demonstrated 87·5% sensitivity and 96·5% specificity with samples from naturally and experimentally infected dogs withEchinococcusorTaeniainfections. In both the humanTaeniaand canineEchinococcusstudies antigen could be detected in faecal samples from infected hosts stored in 5% formalin for 6 months. Further refinements to these tests for field application are discussed.