Immunodiagnosis of taeniasis by coproantigen detection

Abstract

Immunodiagnostic tests for Taenia-specific faecal antigen based on polyclonal rabbit antisera against Taenia saginata or Taenia solium proglottid extracts in capture-type ELISA assays have been developed. Taenia-specific antigen was detected in detergent-solubilized faecal extracts from T. solium- and T. saginata-infected hosts. Coproantigen from T. solium-infected hamsters did not cross-react with faeces from rodents infected with Hymenolepis diminuta, H. citelli, H. microstoma, Necator americanus, Strongyloides ratti or Nematospiroides dubius and faeces from uninfected animals. When the T. saginata-capture ELISA was tested with faecal samples positive for T. solium antigen, no cross-reactions were obtained. However, faecal samples from humans infected with T. solium or T. saginata, including some with extremely low egg counts, were cross-reactive by either test. Nevertheless, considerably higher O.D. values were obtained with stool samples from Taenia patients compared to Hymenolepis nana-infected or uninfected individuals. Two individuals, infected with Taenia sp. and positive for coproantigens by ELISA, became antigen-negative 6 days after treatment with Niclosamide. The possibility of developing species-specific immunodiagnostic tests for human taeniasis through coproantigen detection is discussed.

Diagnosis of human taeniasis

“…The first method of coproantigen (parasite antigens in human stool) detection using enzyme-linked immunosorbent assay (ELISA) was developed by Allan et al 6 . Although the test displayed a higher sensitivity and specificity than microscopic diagnosis for the detection of Taenia spp.…”

New approaches in the diagnosis ofTaenia soliumcysticercosis and taeniasis

“…When a similar test was developed for human taeniasis T. solium and T. saginata samples were cross reactive using polyclonal rabbit antisera but no cross reaction was shown with any other gut helminths including Hymenolepis nana (Allan et al, 1990). Antigen levels have been shown to be present in the absence of eggs and to reach a plateau several weeks before the onset of patency in Taenia pisi formis infections of dogs (Kinder et al, unpublished obser vations).…”

Epidemiología y control de la cisticercosis en el Perú

“…El método clásico de examen microscópico luego de sedimentar la muestra tiene alta especificidad, pero desafortunadamente baja sensibilidad (5) . Existe una prueba de ELISA para detectar antígenos parasitarios en heces (coproantígenos), que tiene mucha mas sensibilidad pero cuyo uso es aún restringido al contexto experimental y no se encuentra en los centros asistenciales (6) . La neurocisticercosis se diagnostica por exámenes de imagen (tomografía computarizada o resonancia magnética) (Figura 1), confirmándose por serología con la técnica de western blot (7) .…”

“…5 Facultad de Salud Pública y Administración, Universidad Peruana Cayetano Heredia, Lima, Perú. 6 Georgia State University, Atlanta, Georgia, USA. …”