Parasitology

Research Article

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

J. C. Allana1, P. S. Craiga1, J. Garcia Novala2, F. Mencosa2, D. Liua3, Y. Wanga4, H. Wena5, P. Zhoua5, R. Stringera1, M. Rogana1 and E. Zeyhlea6

a1 Department of Parasitology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK

a2 Centro de Investigaciones de Ciencias de la Salud, Universidad de San Carlos de Guatemala, Guatemala, C.A.

a3 Department of Parasitology, Lanzhou Medical College, Lanzhou, Gansu, People's Republic of China

a4 Department of Public Health, Min County, Gansu, People's Republic of China

a5 Department of Parasitology, Xinjiang Medical College, Urumqi, Xinjiang, Uygur Autonomous Region, People's Republic of China

a6 African Medical Research Foundation, P.O. Box 30125, Nairobi, Kenya

Abstract

Three ELISA assays, based on hyperimmune rabbit serum raised against adult cestode somatic antigen, were applied in this study for the detection of Taenia- and Echinococcus-specific antigens in host faeces. The first assay, using an antiserum against Taenia pisiformis antigen extract, was used in a time-course of T. pisiformis experimental 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 of T. pisiformis egg output. The second assay, involving a test for human taeniasis based on antibodies against T. 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 for E. granulosus and demonstrated 87·5% sensitivity and 96·5% specificity with samples from naturally and experimentally infected dogs with Echinococcus or Taenia infections. In both the human Taenia and canine Echinococcus studies 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.

(Received June 28 1991)

(Revised October 07 1991)

(Accepted October 10 1991)

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