A dot-ELISA using a partially purified cathepsin-L-like protein fraction from Taenia solium cysticerci, for the diagnosis of human neurocysticercosis

Abstract

Human neurocysticercosis (NCC), caused by the cestode Taenia solium, is responsible for a significant amount of neurological morbidity and epilepsy in developing countries. The disease remains highly endemic in many areas, despite several efforts and interventions to control it. A simple, cheap and fast diagnostic assay that is suitable for use in field conditions is highly desired. In immunodiagnostics based on western immunoblots or standard ELISA, a cathepsin-L-like protein purified from the cysticercus fluid has previously performed well as an antigen. In a recent study in Peru, the same 53/25-kDa antigen was therefore used in the development of a dot-ELISA that could be employed for mass screenings under field conditions. The assay was standardized and tested not only against sera from a large group of NCC cases but also against sera from patients with other common parasitic infections, so that sensitivity and specificity could be assessed. For NCC, the assay gave better sensitivity in the detection of individuals with extraparenchymal cysts (94·4%–100%) or multiple parenchymal cysts (74·6%–80·0%) than in the detection of individuals with single parenchymal cysts (29·4%–45·1%). The assay also showed a high specificity for NCC (99·0%–100%), with a very low level of cross-reactivity with other parasitic infections. The dot-ELISA developed in this study is a highly specific, simple, cheap and rapid test for NCC that could be used under field conditions, even in the low-resource settings that are common in developing countries.

The authors are very grateful to Dr F. Herhold for her careful revision and editing of the manuscript. This work was partially funded by research or training grants from the International Centre for Genetic Engineering and Biotechnology (CRP/PER08-02), the United Nations Children’s Fund/United Nations Development Programme/World Bank/World Health Organization’s Special Programme for Research and Training in Tropical Diseases (A90042), the Fogarty International Center (TW001140) and the United States National Institutes of Health (D43 TW007120). One of the authors (H.H.G.) is now a Wellcome Trust Senior Research Fellow. The sponsors had no role in the design or writing of this manuscript.