Taenia solium DNA is present in the cerebrospinal fluid of neurocysticercosis patients and can be used for diagnosis

Serological and molecular detection of neurocysticercosis among epileptic patients in Nagpur, Maharashtra state (India)

Neurocysticercosis (NCC), one of the most important neuroparasitic diseases in humans, is caused by Cysticercus cellulosae, the metacestode stage of digenetic zoonotic cestode Taenia solium. The present study aims at the detection of anti-cysticercus antibodies in the sera of epileptic patients (n=26) visiting a tertiary care hospital in Nagpur, Maharashtra state, India, by an in-house developed indirect IgG-ELISA and enzyme-linked immunoelectro transfer blot (EITB) assay using different antigens (namely, Whole Cyst Antigen (WCA), Cystic Fluid Antigen (CFA), Scolex Antigen (SA), Excretory-Secretory Antigen (ESA) and Membrane-Body Antigen (MBA)) prepared from T. solium metacestodes to find out the status of NCC. An attempt has also been made for molecular detection of NCC from blood samples of those patients by Polymerase Chain Reaction (PCR) assay targeted at large subunit rRNA gene of T. solium. The IgG ELISA level of anti-cysticercus antibodies against WCA, CFA, SA, ESA and MBA antigens were as follows: 19.23 %, 23.07 %, 38.46 %, 30.76 % and 15.38 %. The seroreactivity to CFA, SA and ESA was found in equal proportions in patients with ring-enhancing lesions. In the EITB assay, the lower and medium molecular weight protein bands of SA and ESA were immunodominant compared to the higher WCA and CFA peptides. PCR positivity could be observed in 34.6 % (9/26) of the patients under study. It is the first report of detecting NCC among epileptic patients of the Nagpur region of Maharashtra state in India using serological and molecular tools.

Cell-free DNA-based liquid biopsies in neurology

This article reviews recent developments in the application of cell-free DNA-based liquid biopsies to neurological diseases. Over the past few decades, an explosion of interest in the use of accessible biofluids to identify and track molecular disease has revolutionized the fields of oncology, prenatal medicine and others. More recently, technological advances in signal detection have allowed for informative analysis of biofluids that are typically sparse in cells and other circulating components, such as CSF. In parallel, advancements in epigenetic profiling have allowed for novel applications of liquid biopsies to diseases without characteristic mutational profiles, including many degenerative, autoimmune, inflammatory, ischaemic and infectious disorders. These events have paved the way for a wide array of neurological conditions to benefit from enhanced diagnostic, prognostic, and treatment abilities through the use of liquid biomarkers: a 'liquid biopsy' approach. This review includes an overview of types of liquid biopsy targets with a focus on circulating cell-free DNA, methods used to identify and probe potential liquid biomarkers, and recent applications of such biomarkers to a variety of complex neurological conditions including CNS tumours, stroke, traumatic brain injury, Alzheimer's disease, epilepsy, multiple sclerosis and neuroinfectious disease. Finally, the challenges of translating liquid biopsies to use in clinical neurology settings-and the opportunities for improvement in disease management that such translation may provide-are discussed.

Update on the diagnosis and management of neurocysticercosis

ABSTRACT Background: Neurocysticercosis (NCC) is a serious public health problem in several developing countries, including those in Latin America, Asia, and Africa. NCC is considered to be the main cause of late-onset epilepsy in endemic areas. Objective: This review summarizes recent advances in diagnosis and therapy of NCC. Methods: Relevant articles and books were reviewed and used as a source of information for this review. Results: The diagnosis of NCC is based upon neuroimaging studies (MRI and computed tomography) and laboratory analysis of the cerebrospinal fluid (CSF). Praziquantel and albendazole are considered parasiticidal drugs against NCC, but there is an intense debate over the value and safety of these drugs. Conclusion: Given the relative scarcity of clinical trials, more comparative interventional studies, especially randomized controlled trials in long-term clinical evolution, are required in order to clarify the controversy over the validity of parasitic therapy in patients with NCC.

Selection of new diagnostic markers for Dirofilaria repens infections with the use of phage display technology

Dirofilaria repens is a parasitic nematode causing vector-borne disease (dirofilariasis), considered an emerging problem in veterinary and human medicine. Although main hosts are carnivores, particularly dogs, D. repens shows high zoonotic potential. The disease spreads uncontrollably, affecting new areas. Since there is no vaccine against dirofilariasis, the only way to limit disease transmission is an early diagnosis. Currently, diagnosis depends on the detection of microfilariae in the host bloodstream using modified Knott's test or multiplex PCR. However, the efficacy of tests relying on microfilariae detection is limited by microfilariae periodic occurrence. Therefore, a new reliable diagnostic test is required. Our study aimed to select new diagnostic markers for dirofilariasis with potential application in diagnostics. We focused on single epitopes to ensure high specificity of diagnosis and avoid cross-reactivity with the other parasite infections common in dogs. Using phage display technology and 12-mer peptides library, we selected epitopes highly reactive with IgG from sera of infected dogs. Additionally, our study presents the possibility of detecting D. repens specific cell-free DNA in dogs with no microfilaria but high IgG and IgM antibody levels against parasite somatic antigen.

Collaborative Studies for the Detection of Taenia spp. Infections in Humans within CYSTINET, the European Network on Taeniosis/Cysticercosis

Laboratory tools for diagnosing taeniosis/cysticercosis in non-endemic countries are available; however, there is little data on their performance. To provide information on the sensitivity, specificity, and reproducibility of these tools, inter-laboratory studies were organized within the EU COST-Action CYSTINET (TD1302). Two serological and one coprological Ring Trials (RTs) were organized to test a panel of human-derived sera and stool samples using assays routinely conducted by the participating laboratories to detect Taenia spp. infections. Four Western blots (WBs) and five ELISAs were used by nine laboratories for cysticercosis diagnosis. In the first serological RT, the overall sensitivity was 67.6% (95% CI, 59.1-75.4), whereas specificity was 97% (95% CI, 89.8-99.6). WBs recorded the best accuracy. A second serological RT was organized, to assess the three tests most frequently used during the first RT. Two out of six laboratories performed all the three tests. The overall sensitivity and specificity were 52.8% (95% CI, 42.8-62.7) and 98.1% (95% CI, 93.2-99.7), respectively. Laboratory performance strongly affected test results. Twelve laboratories participated in the coprological RT using conventional microscopy and six laboratories used molecular assays. Traditional diagnosis by microscopy yielded better results than molecular diagnosis. This may have been influenced by the lack of standardization of molecular tests across participating laboratories.

Neurocysticercosis Diagnosed by Taenia solium PCR on Brain Biopsy

Neurocysticercosis is a common cause for brain lesions and adult-onset epilepsy in endemic countries. However, diagnosis is challenging in the absence of typical radiologic or histopathologic features. In this case report, we present a case of a 35-year-old male with a new-onset seizure and a rim-enhancing temporal lobe lesion. Radiologic features were nonspecific, and brain biopsy was performed. Histologic features showed only nonspecific granulomatous inflammation, and the diagnosis of neurocysticercosis was confirmed only with polymerase chain reaction (PCR) testing on brain biopsy tissue demonstrating PCR products consistent with Taenia solium. This case highlights the diagnostic role of PCR in such clinical situations whereby the diagnosis is unclear after initial routine evaluation.

Epilepsy due to Neurocysticercosis: Analysis of a Hospital Cohort

Introduction: Neurocysticercosis (NCC) is a common helminthic infection of the nervous system that occurs when humans become intermediate hosts in the life cycle of the pig tapeworm (Taenia solium) after ingesting its eggs. The objective of this study was to analyze socio-demographic, clinical and paraclinical features of patients with NCC in Lubumbashi, DRC. Methods: This is a cross-sectional study conducted over a period of 2 years within the Neuropsychiatric Center of Lubumbashi. Socio-demographic, clinical, paraclinical and therapeutic features were studied. Results: A total of 18 patients with NCC were listed. Epilepsy was found in 72.2% (13/18) of the cases. The mean age of the patients was 30.2 ± 13.5 years; males accounted for 61.2% of the cases. 84.6% were consumers of pork. Generalized epilepsy was found in 84.6% of the cases and hypereosinophilia in 38% of the cases. On the neuroimaging, the parietal location of lesions represented 92.3%; calcifications were the type of lesion in 53.8% of the cases and 69.2% of the cases presented lesions in the 4th evolutionary stage. Electroencephalogram was normal in 84.4% of the cases. Phenobarbital was the antiepileptic drug used in 69.3%; albendazole and prednisone were used in 53.9% of the cases. Conclusion: This study shows that NCC is one of the causes of epilepsy in Lubumbashi. Generalized tonic-clonic seizures are the most common form of presentation and calcified parenchymal lesions are the most common radiological feature of NCC. So, any patient with acute onset of afebrile seizure should be screened for NCC provided other common causes been ruled out.

Detection of Taenia solium DNA in the Urine of Neurocysticercosis Patients

Neurocysticercosis (NCC), caused by Taenia solium larvae that reside in the central nervous system, results in serious public health and medical issues in many regions of the world. Current diagnosis of NCC is complex requiring both serology and costly neuroimaging of parasitic cysts in the brain. This diagnostic pipeline can be problematic in resource-constrained settings. There is an unmet need for a highly sensitive and clinically informative diagnostic test to complement the present diagnostic approaches. Here, we report that T. solium-derived cell-free DNA is readily detectable in the urine of patients with the subarachnoid and parenchymal forms of NCC, and discuss the potential utility of this approach in enhancing and refining T. solium diagnostics.

Comparison of complementary diagnostic tests in cerebrospinal fluid and serum for neurocysticercosis

The role of immunologic tests in the diagnosis of neurocysticercosis (NC) is controversial and few studies have made comparisons among them. The objective of this study was to compare immunological tests in both serum and cerebrospinal fluid (CSF) for the diagnosis of NC. We conducted a case-control study in Cuenca, Ecuador, enrolling patients with NC (N = 24) and matching them with other neurosurgical patients (N = 18). To detect cysticercal antigen, we used an HP10 antigen assay in serum and CSF (“HP10 Ag -serum -CSF”) and a commercial antigen assay in serum (apDia, “ELISA-Ag-serum”), and to detect cysticercal DNA, we used a polymerase chain reaction (PCR) assay in CSF (“PCR-CSF”). Assay sensitivities were: HP10 Ag-serum (41.7%, 95% confidence interval [CI] 22.1–63.4), HP10 Ag-CSF (87.5%, 95% CI: 67.6–97.3), ELISA-Ag-serum (62.5%, 95% CI: 40.6–81.2), and PCR-CSF (79.2%, 95% CI: 57.9–92.9). Sensitivities were higher when limiting to participants with extraparenchymal NC. Specificity was 100% for all assays except ELISA-Ag-serum (72.2%). This preliminary study demonstrated the potential usefulness of the PCR and HP10 Ag assay in CSF, especially for extraparenchymal NC; thus, they could be considered as complementary diagnostic tools when neuroimaging is not conclusive.

Next-Generation Sequencing of Cerebrospinal Fluid for the Diagnosis of Neurocysticercosis

Background: Neurocysticercosis (NCC) is the most common helminthic infection of the central nervous system (CNS). The diagnosis of NCC is sometimes challenging due to its heterogenous clinical manifestations and the variable sensitivity and specificity of neuroimaging and serological tests. Methods: Next-generation sequencing (NGS) of cerebrospinal fluid (CSF) was used to detect pathogens in patients with clinically suspected CNS infections. A series of patients diagnosed with NCC is reviewed here. Results: Using NGS of CSF, four patients were diagnosed with NCC. The reads corresponding to Taenia solium ranged from 478 to 117,362, with genomic coverage of 0.0564-11.15%. Reads corresponding to T. solium were not found in non-template controls and far exceeded those of the background microorganisms in patients with NCC, facilitating the interpretation of the NGS results. Conclusions: This case series demonstrates that NGS of CSF is promising in the diagnosis of NCC in difficult to diagnose cases. Larger studies are needed in the future.

Next generation sequencing based pathogen analysis in a patient with neurocysticercosis: a case report

BACKGROUND

Accurate and early diagnosis of neurocysticercosis (NCC) remains a challenge due to the heterogeneity of its clinical, immunological and imaging characteristics. The presence of cysticercus DNA in cerebrospinal fluid (CSF) of NCC patients has been previously detected via conventional PCR assays. To the best of our knowledge, the use of CSF Next-Generation Sequencing (NGS) based pathogen analysis in patients with NCC infection has never been reported.

CASE PRESENTATION

This study reports the clinical, imaging, and immunological features of a patient initially presenting with several months of headache who further developed a pure sensory stroke. NGS was used to detect the pathogen, and her CSF demonstrated the presence of Taenia solium-DNA. This finding was confirmed by a positive reaction to CSF cysticercosis antibodies. After antiparasitic treatment, secondary CSF NGS revealed the DNA index have dropped considerably compared to the initial NGS readings.

CONCLUSIONS

NGS is a promising tool for the early and accurate diagnosis of central nervous system (CNS) infection, especially in the setting of atypical clinical manifestations. Further studies are required to evaluate the persistence of DNA in the CSF of patients.

Present status of laboratory diagnosis of human taeniosis/cysticercosis in Europe

Human cysticercosis (CC) is a parasitic zoonosis caused by the larval stage (cyst) of the Taenia solium. Cysts can establish in the human central nervous system (neurocysticercosis, NCC) and other organs and tissues; they also develop in pigs, the natural intermediate host. Human taeniosis may be caused by T. solium, Taenia saginata and Taenia asiatica tapeworms; these infections are usually asymptomatic, but show a significant relevance as they perpetuate the parasites’ life cycle, and, in the case of T. solium, they are the origin of (N)CC. In European Union (EU) member states and associated countries, the occurrence of autochthonous T. solium cases is debated, and imported cases have significantly increased lately; the status of T. asiatica has been never reported, whereas T. saginata is prevalent and causes an economic impact due to condemned carcasses. Based on their effects on the EU society, the specific diagnosis of these pathologies is relevant for their prevention and control. The aims of this study were to know the diagnostic tests used in European laboratories for human taeniosis/cysticercosis by means of a questionnaire, to determine potential gaps in their detection, and to obtain preliminary data on the number of diagnosed taeniosis/CC cases.

Validity of a PCR assay in CSF for the diagnosis of neurocysticercosis

Objective:

To prospectively evaluate the validity of a PCR assay in CSF for the diagnosis of neurocysticercosis (NC).

Methods:

We conducted a multicenter, prospective case-control study, recruiting participants from 5 hospitals in Cuenca, Ecuador, from January 2015 to February 2016. Cases fulfilled validated diagnostic criteria for NC. For each case, a neurosurgical patient who did not fulfill the diagnostic criteria for NC was selected as a control. CT and MRI, as well as a CSF sample, were collected from both cases and controls. The diagnostic criteria to identify cases were used as a reference standard.

Results:

Overall, 36 case and 36 control participants were enrolled. PCR had a sensitivity of 72.2% (95% confidence interval [CI] 54.8%–85.8%) and a specificity of 100.0% (95% CI 90.3%–100.0%). For parenchymal NC, PCR had a sensitivity of 42.9% (95% CI 17.7%–71.1%), and for extraparenchymal NC, PCR had a sensitivity of 90.9% (95% CI 70.8%–98.9%).

Conclusions:

This study demonstrated the usefulness of this PCR assay in CSF for the diagnosis of NC. PCR may be particularly helpful for diagnosing extraparenchymal NC when neuroimaging techniques have failed.

Classification of evidence:

This study provides Class III evidence that CSF PCR can accurately identify patients with extraparenchymal NC.

Cysticercosis/taeniasis endemicity in Southeast Asia: Current status and control measures

The parasitic zoonoses cysticercosis/taeniasis is among the 17 major Neglected Tropical Diseases (NTDs) identified by the WHO as a focus for research and control. It is caused by a larval stage (cysticercus) infection of Taenia solium tapeworm in both humans and pigs. Cysticercosis occurs in many resource-poor countries, especially those with warm and mild climates in the regions of Latin America (LA), Asia and Sub-Saharan Africa (SSA). The prevalence of human cysticercosis is marked in those areas where individuals are traditionally keen to consume raw or insufficiently cooked pork and/or where the husbandry of pigs is improper. The worldwide burden of cysticercosis is unclear and notably, large-scale control initiatives are lacking in all regions. This review focuses on the current endemic status of cysticercosis caused by T. solium infection in both humans and pigs living in 13 Southeast Asian countries. We will also emphasize epidemiological data as well as prevention and control of human neurocysticercosis.

Molecular testing for clinical diagnosis and epidemiological investigations of intestinal parasitic infections

Over the past few decades, nucleic acid-based methods have been developed for the diagnosis of intestinal parasitic infections. Advantages of nucleic acid-based methods are numerous; typically, these include increased sensitivity and specificity and simpler standardization of diagnostic procedures. DNA samples can also be stored and used for genetic characterization and molecular typing, providing a valuable tool for surveys and surveillance studies. A variety of technologies have been applied, and some specific and general pitfalls and limitations have been identified. This review provides an overview of the multitude of methods that have been reported for the detection of intestinal parasites and offers some guidance in applying these methods in the clinical laboratory and in epidemiological studies.

Cell-Free DNA as a Diagnostic Tool for Human Parasitic Infections

Parasites often cause devastating diseases and represent a significant public health and economic burden. More accurate and convenient diagnostic tools are needed in support of parasite control programmes in endemic regions, and for rapid point-of-care diagnosis in nonendemic areas. The detection of cell-free DNA (cfDNA) is a relatively new concept that is being applied in the current armamentarium of diagnostics. Here, we review the application of cfDNA detection with nucleic acid amplification tests for the diagnosis and evaluation of different human parasitic infections and highlight the significant benefits of the approach using non-invasive clinical samples.

Application of polymerase chain reaction on cerebrospinal fluid for diagnosis of cerebral coenurosis in small ruminants

Sheep and goats serve as intermediate hosts for the canine tapeworm Taenia multiceps. The cysts produced by the intermediate stage of parasite are usually found in the cerebral hemispheres of small ruminants, and the resulting disease is commonly known as coenurosis. Coenurosis is clinically manifested in the form of various nervous symptoms, depending on the exact location of the cyst. The variety of neurological symptoms contributes to the complexity of clinical diagnosis and reinforces the need for a more specific and acceptable diagnostic approach. We demonstrated here, for the first time, that the T. multiceps DNA is present in the cerebrospinal fluid (CSF) of the infected sheep and goats. In addition, the molecular genetic marker of the mitochondrial DNA was applied phylogenetically to show that our isolates together with other T. multiceps strains comprised a monophyletic group that is a sister to Taenia krabbei. Pairwise comparison between the cox1 sequences of our study and other T. multiceps genotypes existing in the GenBank showed similarity ranging from 98 to 100%. Accordingly, the polymerase chain reaction (PCR) can be used for amplification of DNA of the parasite originated from the CSF and provides a valuable method for accurate identification of coenurosis cases.

Inhibition of store-operated calcium entry in microglia by helminth factors: implications for immune suppression in neurocysticercosis

Background

Neurocysticercosis (NCC) is a disease of the central nervous system (CNS) caused by the cestode Taenia solium. The infection exhibits a long asymptomatic phase, typically lasting 3 to 5 years, before the onset of the symptomatic phase. The severity of the symptoms is thought to be associated with the intensity of the inflammatory response elicited by the degenerating parasite. In contrast, the asymptomatic phase shows an absence of brain inflammation, which is presumably due to immunosuppressive effects of the live parasites. However, the host factors and/or pathways involved in inhibiting inflammation remain largely unknown. Recently, using an animal model of NCC in which mice were intracranially inoculated with a related helminth parasite, Mesocestoides corti, we reported that Toll-like receptor (TLR)-associated signaling contributes to the development of the inflammatory response. As microglia shape the initial innate immune response in the CNS, we hypothesized that the negative regulation of a TLR-induced inflammatory pathway in microglia may be a novel helminth-associated immunosuppressive mechanism in NCC.

Methods and results

Here we report that helminth soluble factors (HSFs) from Mesocestoides corti inhibited TLR ligation-induced production of inflammatory cytokines in primary microglia. This was correlated with an inhibition of TLR-initiated upregulation of both phosphorylation and acetylation of the nuclear factor κB (NF-κB) p65 subunit, as well as phosphorylation of JNK and ERK1/2. As Ca²⁺ influx due to store-operated Ca²⁺ entry (SOCE) has been implicated in induction of downstream signaling, we tested the inhibitory effect of HSFs on agonist-induced Ca²⁺ influx and specific Ca²⁺ channel activation. We discovered that HSFs abolished the lipopolysaccharide (LPS)- or thapsigargin (Tg)-induced increase in intracellular Ca²⁺ accumulation by blocking the ER store release and SOCE. Moreover, electrophysiological recordings demonstrated HSF-mediated inhibition of LPS- or Tg-induced SOCE currents through both TRPC1 and ORAI1 Ca²⁺ channels on plasma membrane. This was correlated with a decrease in the TRPC1-STIM1 and ORAI1-STIM1 clustering at the plasma membrane that is essential for sustained Ca²⁺ entry through these channels.

Conclusion

Inhibition of TRPC1 and ORAI1 Ca²⁺ channel-mediated activation of NF-κB and MAPK pathways in microglia is likely a novel helminth-induced immunosuppressive mechanism that controls initiation of inflammatory response in the CNS.

Overview of the effect and epidemiology of parasitic central nervous system infections in African children

Infections of the central nervous system are a significant cause of neurologic dysfunction in resource-limited countries, especially in Africa. The prevalence is not known and is most likely underestimated because of the lack of access to accurate diagnostic screens. For children, the legacy of subsequent neurodisability, which affects those who survive, is a major cause of the burden of disease in Africa. Of the parasitic infections with unique effect in Africa, cerebral malaria, neurocysticercosis, human African trypanosomiasis, toxoplasmosis, and schistosomiasis are largely preventable conditions, which are rarely seen in resource-equipped settings. This article reviews the current understandings of these parasitic and other rarer infections, highlighting the specific challenges in relation to prevention, diagnosis, treatment, and the complications of coinfection.

High prevalence of cysticercosis in people with epilepsy in southern Rwanda

Background

Neurocysticercosis (NCC), the central nervous system infection by Taenia solium larvae, is a preventable and treatable cause of epilepsy. In Sub-Saharan Africa, the role of NCC in epilepsy differs geographically and, overall, is poorly defined. We aimed at contributing specific, first data for Rwanda, assessing factors associated with NCC, and evaluating a real-time PCR assay to diagnose NCC in cerebrospinal fluid (CSF).

Methodology/Principal findings

At three healthcare facilities in southern Rwanda, 215 people with epilepsy (PWE) and 51 controls were clinically examined, interviewed, and tested by immunoblot for cysticerci-specific serum antibodies. Additionally, CSF samples from PWE were tested for anticysticercal antibodies by ELISA and for parasite DNA by PCR. Cranial computer tomography (CT) scans were available for 12.1% of PWE with additional symptoms suggestive of NCC. The Del Brutto criteria were applied for NCC diagnosis. Cysticerci-specific serum antibodies were found in 21.8% of PWE and 4% of controls (odds ratio (OR), 6.69; 95% confidence interval (95%CI), 1.6–58.7). Seropositivity was associated with age and lack of safe drinking water. Fifty (23.3%) PWE were considered NCC cases (definitive, based on CT scans, 7.4%; probable, mainly based on positive immunoblots, 15.8%). In CSF samples from NCC cases, anticysticercal antibodies were detected in 10% (definitive cases, 25%) and parasite DNA in 16% (definitive cases, 44%). Immunoblot-positive PWE were older (medians, 30 vs. 22 years), more frequently had late-onset epilepsy (at age >25 years; 43.5% vs. 8.5%; OR, 8.30; 95%CI, 3.5–20.0), and suffered from significantly fewer episodes of seizures in the preceding six months than immunoblot-negative PWE.

Conclusions/Significance

NCC is present and contributes to epilepsy in southern Rwanda. Systematic investigations into porcine and human cysticercosis as well as health education and hygiene measures for T. solium control are needed. PCR might provide an additional, highly specific tool in NCC diagnosis.

Neurocysticercosis (NCC) is the infection of the brain with larvae of the pig tapeworm (Taenia solium), which results from the ingestion of, e.g., food or water contaminated with the eggs of this helminth. Seizures and epilepsy are the most often reported clinical manifestations. The diagnosis is based on various clinical, radiological, microbiological, and epidemiological criteria. NCC is treatable and preventable. Knowledge about its contribution to epilepsy in a given region therefore helps to manage and prevent the disease. Our study aimed at investigating the prevalence of and risk factors associated with NCC in southern Rwanda. Additionally, we evaluated a new diagnostic method based on the detection of parasite DNA in the cerebrospinal fluid of people with epilepsy for its usefulness. By applying well-established diagnostic criteria for NCC, we identified 16 definitive and 34 probable NCC cases among 215 people with epilepsy in southern Rwanda. The risk of NCC was higher in those lacking access to safe drinking water. This highlights opportunities for the prevention of NCC, and consequently, epilepsy in this region. Parasite DNA could be detected in the cerebrospinal fluid of 16% of the NCC patients. Thus, this method might help to identify NCC cases, particularly when radiology cannot be performed easily.

Immunological and molecular diagnosis of cysticercosis

Cysticercosis, the infection with the larval stage of Taenia solium, is a cause of neurological symptoms including seizures, affecting the quality of life of patients and their families. Diagnosis focuses on brain imaging and serological tests are mostly used as confirmatory tools. Most cases, however, occur in poor endemic areas, where both kinds of diagnostic tools are poorly available. Development of point of care diagnostic tests is one of the most important priorities for cysticercosis researches today. The ideal point of care test would require detection of viable cysticercosis and hopefully identify cases with severe or progressive forms of neurocysticercosis, leading to referral of the patient for specialized medical attention. This manuscript describes the evolution of the serological diagnosis of cysticercosis over time, and the characteristics of the most common currently available tools, their advantages and disadvantages, and their potential use in future diagnostic tests.

Neurocysticercosis: Five new things

Neurocysticercosis is the most common parasitic brain disease worldwide. Its clinical heterogeneity is related to localization, number and stage of evolution of the parasites, sex, age, and intensity of the host brain inflammatory reaction. In addition to the localization of the parasite, inflammation is the main phenomenon responsible of symptomatology. Acute symptomatic seizures are the most common symptom in patients with parenchymal parasites, but most do not evolve into epilepsy. Neurocysticercosis diagnosis is based mainly on neuroimaging. New imaging techniques have improved detection of the scolex and visualization of cysts in the extraparenchymal spaces. Immunologic testing can be useful, particularly when imaging is equivocal. Based on disappearance of parasites, antihelminthic drugs as currently used are effective in approximately one-third of patients with parenchymal viable cysts.

Neurocysticercosis in sub-Saharan Africa: a review of prevalence, clinical characteristics, diagnosis, and management

Neurocysticercosis has been recognized as a major cause of secondary epilepsy worldwide. So far, most of the knowledge about the disease comes from Latin America and the Indian subcontinent. Unfortunately, in sub-Saharan Africa the condition was neglected for a long time, mainly owing to the lack of appropriate diagnostic tools. This review therefore focuses on the prevalence of neurocysticercosis in sub-Saharan Africa, the clinical picture with emphasis on epilepsy, as well as the diagnosis and treatment of neurocysticercosis and its related epilepsy/epileptic seizures in African resource-poor settings.

Medical management of neurocysticercosis

INTRODUCTION

Neurocysticercosis (NCC) is considered to be the most common cause of acquired epilepsy worldwide. Formerly restricted to palliative measures, therapy for NCC has advanced with the advent of two drugs that are considered to be effective: praziquantel (PZQ) and albendazole (ALB).

AREAS COVERED

All available articles regarding research related to the treatment of NCC were searched. Relevant articles were then reviewed and used as sources of information for this review.

EXPERT OPINION

Anticysticercal therapy has been marked by intense controversy. Recent descriptions of spontaneous resolution of parenchymal cysticercosis with benign evolution, risks of complications and reports of no long-term benefits have reinforced the debate over the usefulness and safety of anticysticercal therapy. High interindividual variability and complex pharmacological interactions will require the close monitoring of plasma concentrations of ALB and PZQ metabolites in future trials. Given the relative scarcity of clinical trials, more comparative interventional studies - especially randomized controlled trials in long-term clinical evolution - are required to clarify the controversy over the validity of parasitic therapy in patients with NCC.

Immunodiagnosis of neurocysticercosis: ways to focus on the challenge

Neurocysticercosis (NCC) is a disease of the central nervous system that is considered a public health problem in endemic areas. The definitive diagnosis of this disease is made using a combination of tools that include imaging of the brain and immunodiagnostic tests, but the facilities for performing them are usually not available in endemic areas. The immunodiagnosis of NCC is a useful tool that can provide important information on whether a patient is infected or not, but it presents many drawbacks as not all infected patients can be detected. These tests rely on purified or semipurified antigens that are sometimes difficult to prepare. Recent efforts have focused on the production of recombinant or synthetic antigens for the immunodiagnosis of NCC and interesting studies propose the use of new elements as nanobodies for diagnostic purposes. However, an immunodiagnostic test that can be considered as "gold standard" has not been developed so far. The complex nature of cysticercotic disease and the simplicity of common immunological assumptions involved explain the low scores and reproducibility of immunotests in the diagnosis of NCC. Here, the most important efforts for developing an immunodiagnostic test of NCC are listed and discussed. A more punctilious strategy based on the design of panels of confirmed positive and negative samples, the use of blind tests, and a worldwide effort is proposed in order to develop an immunodiagnostic test that can provide comparable results. The identification of a set of specific and representative antigens of T. solium and a thorough compilation of the many forms of antibody response of humans to the many forms of T. solium disease are also stressed as necessary.

Confirmation and follow-up of neurocysticercosis by real-time PCR in cerebrospinal fluid samples of patients living in France

Neurocysticercosis diagnosis is based on a combination of clinical, epidemiological, radiological, and immunological findings. We describe a real-time PCR assay for the confirmation of neurocysticercosis diagnosis in cerebrospinal fluid. The assay, tested on samples from nine patients living in France and diagnosed with neurocysticercosis, had a detection rate of 83.3% and 100% specificity.

Human neurocysticercosis: comparison of different diagnostic tests using cerebrospinal fluid

Neurocysticercosis (NC), caused by the larval stage of Taenia solium, is one of the most common parasitic diseases of the central nervous system. The diagnosis of NC is mostly based on costly brain neuroimaging (computed tomography and/or nuclear magnetic resonance), which is rarely accessible in most affected areas. The most sensitive and specific tools for NC diagnosis are imagery techniques. The identification of specific antibodies and antigens is currently used only to support NC diagnosis due to their limited specificity and sensitivity. This study was performed to compare immunodiagnostic assays (antibody detection by enzyme-linked immunosorbent assay [ELISA] and enzyme-linked immunoelectrotransfer blotting [EITB] and HP10 antigen detection by ELISA) with the detection of parasite DNA by PCR amplification of a repetitive element of the parasite genome in the cerebrospinal fluid (CSF) of 121 radiologically and clinically characterized NC patients. Patients were divided into six groups according to the stage of the parasites and their localization. The CSF cellularity of each patient was also recorded. When all patients were considered, PCR exhibited the highest sensitivity (95.9%) and variable specificity (80% or 100%) depending on the controls used. The sensitivities of antibody detection by ELISA and EITB were not significantly different, and ELISA identified HP10 antigen mostly when vesicular cysticerci were located in the subarachnoideal basal cisterns. These results can help in the selection of different individual assays or combinations of assays to be used in NC diagnosis according to different requirements.

Epilepsy and neurocysticercosis in sub-Saharan Africa

Over the last decades, studies in sub-Saharan Africa have indicated that epilepsy is a highly prevalent neurological disorder. Causes may be varied with infections of the central nervous system playing an important role. Neurocysticercosis (NCC) has recently been recognised as an emerging public health problem and a growing concern throughout sub-Saharan Africa and has been estimated to be responsible for 30-50% of acquired epilepsy. NCC is closely linked with porcine cysticercosis and human taeniosis, the former reaching a prevalence of almost 50% in some pig populations. In this review, we first summarize prevalence data on epilepsy and highlight some special aspects of the disorder within sub-Saharan Africa. We then focus on the prevalence of NCC, clinical signs and symptoms and diagnostic criteria for NCC with special reference to sub-Saharan Africa. This is followed by a section on the latest developments regarding serodiagnosis of cysticercosis and a section on care management of people infected with NCC. NCC clearly represents a major risk factor of epilepsy, thus detecting and treating NCC may help cure epilepsy in millions of people in sub-Saharan Africa.

Update on eosinophilic meningoencephalitis and its clinical relevance

Eosinophilic meningoencephalitis is caused by a variety of helminthic infections. These worm-specific infections are named after the causative worm genera, the most common being angiostrongyliasis, gnathostomiasis, toxocariasis, cysticercosis, schistosomiasis, baylisascariasis, and paragonimiasis. Worm parasites enter an organism through ingestion of contaminated water or an intermediate host and can eventually affect the central nervous system (CNS). These infections are potentially serious events leading to sequelae or death, and diagnosis depends on currently limited molecular methods. Identification of parasites in fluids and tissues is rarely possible, while images and clinical examinations do not lead to a definitive diagnosis. Treatment usually requires the concomitant administration of corticoids and anthelminthic drugs, yet new compounds and their extensive and detailed clinical evaluation are much needed. Eosinophilia in fluids may be detected in other infectious and noninfectious conditions, such as neoplastic disease, drug use, and prosthesis reactions. Thus, distinctive identification of eosinophils in fluids is a necessary component in the etiologic diagnosis of CNS infections.

Transcriptome analysis of Taenia solium cysticerci using Open Reading Frame ESTs (ORESTES)

BACKGROUND

Human infection by the pork tapeworm Taenia solium affects more than 50 million people worldwide, particularly in underdeveloped and developing countries. Cysticercosis which arises from larval encystation can be life threatening and difficult to treat. Here, we investigate for the first time the transcriptome of the clinically relevant cysticerci larval form.

RESULTS

Using Expressed Sequence Tags (ESTs) produced by the ORESTES method, a total of 1,520 high quality ESTs were generated from 20 ORESTES cDNA mini-libraries and its analysis revealed fragments of genes with promising applications including 51 ESTs matching antigens previously described in other species, as well as 113 sequences representing proteins with potential extracellular localization, with obvious applications for immune-diagnosis or vaccine development.

CONCLUSION

The set of sequences described here will contribute to deciphering the expression profile of this important parasite and will be informative for the genome assembly and annotation, as well as for studies of intra- and inter-specific sequence variability. Genes of interest for developing new diagnostic and therapeutic tools are described and discussed.

Diagnosis of neurocysticercosis by detection of Taenia solium DNA using a global DNA screening platform

Neurocysticercosis is caused by Taenia solium infection of the brain. Diagnosis is most often made by visualization of the parasitic scolex by magnetic resonance imaging of the brain or by characteristic neuroimaging findings with serologic test results positive for T. solium. A patient who presents with a solitary brain lesion usually poses a diagnostic dilemma, because the differential diagnosis often includes neurocysticercosis and other infections or neoplasm. Although the sensitivity of serologic testing for T. solium approaches 100% in patients with multiple intraparenchymal cysts, the sensitivity of testing for patients with solitary cysts is <50%, which makes serologic testing a less useful diagnostic tool for patients with solitary central nervous system (CNS) lesions. We describe 2 patients with solitary CNS lesions who received a neurocysticercosis diagnosis after identification of T. solium DNA in brain biopsy tissue with use of a global DNA screening platform. Global screening is a promising tool for the diagnosis of CNS infection, especially when traditional diagnostic tools are insensitive.