Neurocysticercosis: detection ofTaenia soliumDNA in human cerebrospinal fluid using a semi-nested PCR based on HDP2

Abstract

Human neurocysticercosis (NC) is caused by Taenia solium larvae lodged in the central nervous system. This disease is usually diagnosed by radiology but the results are not always clear-cut and so immunological assays are often also used. A semi-nested PCR, based on the non-coding HDP2 sequence of T. saginata, has now been developed for detecting DNA from T. solium cysticerci and confirming NC. This PCR, which amplifies a 171-bp T. solium product, allowed the specific detection of just 174 attograms of T. solium DNA. The efficacy of the PCR was tested using cerebrospinal fluid (CSF) from neurological patients, including 46 confirmed Mexican cases of NC and 32 patients from non-endemic Spain. Eighteen of the confirmed cases [including 10 (71%) of the 14 with vesicular extraparenchymal cysticerci and four (17%) of the 24 with damaged cysticerci] and two (33%) of the six patients with 'uncertain' diagnosis (in whom a diagnosis of NC could not be established by radiological and immunological studies) were found PCR-positive. The 36 patients known to have neurological problems other than NC were found PCR-negative. The HDP2 PCR offers a new tool in the diagnosis of NC and in exploring the pathogenesis of this serious disease.

Human Neurocysticercosis: Comparison of Different Diagnostic Tests Using Cerebrospinal Fluid

“…In the study on HDP2 PCR, two uncertain NC cases were PCR positive (25). The authors suggest that the parasite DNA detected in these cases could be related to the perilesional edema occasionally observed with damaged cysticerci (30).…”

“…In one study, using highly repetitive elements of the parasite as probes, as little as 10 fg of T. solium DNA was detected by PCR in the CSF from 29 out of 30 patients (1). In addition, a seminested PCR based on HDP2 that can detect 0.174 fg of T. solium DNA has been reported (24,25). Here a comparative study of immunological procedures plus the procedure described by Almeida et al (1) were evaluated using CSF from neurological patients from Mexico and France.…”

Epilepsy and Neurocysticercosis in Sub-Saharan Africa

“…However, a positive test only indicates cysticercosis but not necessarily NCC, and the sensitivity and specificity for current infection with Taenia solium cysticercus and prior exposure to the parasite can vary considerably according to the test used [106,108,112]. In addition, polymerase chain reaction (PCR) methods for the diagnosis of Taenia solium cysticercosis are under development, but so far are not part of routine diagnosis due to varying levels of sensitivities and specificities [113,114]. Also, these techniques, with highcost equipment and need for regular maintenance may not be suitable for countries of subSaharan Africa.…”

Cardiac Involvement with Parasitic Infections

“…An enzyme-linked immunoelectrotransfer blot assay is the test of choice for the detection of antibodies (111). PCR-based tests have an emerging role in the epidemiological investigation of taeniasis and are available for the diagnosis of cysticercosis (128,212,354). Most individuals with cysticercosis do not have viable T. solium in their intestines.…”