Evaluation of the ELISA method for diagnosis of human cysticercosis in an endemic region.

Abstract

Introduction. Cysticercosis is a worldwide public health problem. Currently it is diagnosed by detection of specific antibodies or by imaging techniques.
Objective. To evaluate an alternative diagnostic tool, a simple antibody detection assay, called Dot ELISA, for immunological diagnosis of patients with neurocysticercosis as well as for endemic population screening.
Materials And Methods. The test was applied to cysticercosis patients, as well as to healthy controls and individuals with other parasitic infections. A total of 45 serum, 41 plasma and 23 cerebrospinal fluid samples were obtained from patients meeting clinical, surgical, imaging and laboratory criteria for cysticercosis. Samples were processed by enzyme-linked immune-electro-transfer blot assay and by Dot ELISA. Controls included 37 serum, 64 plasma and 17 cerebrospinal fluid samples from healthy individuals without epidemiological history for taeniosis-cysticercosis. Similarly, 43 plasma samples from patients with parasitic infections different from cysticercosis and 663 samples from population survey for cysticercosis were also evaluated.
Results. A total of 933 samples were analyzed. In samples from cysticercosis patients and healthy control individuals, the Dot ELISA test showed an overall sensitivity of 80.7% (CI 95% = 80.2%-81.2%) and a specificity of 92.4% (CI 95% = 91.9%-92.8%). The Dot ELISA performed in serum had a sensitivity of 91.1%, in plasma 85.4%, and in cerebrospinal fluid 52.2%. Similarly, the same test performed in serum, plasma and cerebrospinal fluid, had a specificity of 100%, 85.9% and 100% respectively. The Dot ELISA was applied as a screening test for the diagnosis of cysticercosis in an endemic population in which 1.8% (12/663) of individuals had T. solium antibodies detected by Enzyme-linked immune-electro-transfer blot assay and showed a sensitivity of 58.3% (CI 95% = 54.0-62.7) and a specificity of 100% (CI 95% = 99.9-100.0) with a positive predictive value of 100% and a negative predictive value of 99.2%. All 43 samples from patients with parasitic infections different from cysticercosis were negative for both tests.
Conclusions. These results indicated that Dot ELISA is a promising tool for the diagnosis of cysticercosis as a screening test, as well as for field epidemiological studies.