Detection of HP10 antigen in serum for diagnosis and follow-up of subarachnoidal and intraventricular human neurocysticercosis

Accuracy of immunological tests on serum and urine for diagnosis of Taenia solium neurocysticercosis: A systematic review

BACKGROUND

Taenia solium neurocysticercosis is a zoonotic neglected tropical disease, for which adequate diagnostic management is paramount, especially in patients with active cysts for whom improved and timely management could prove beneficial. Immunodiagnosis can potentially partially mitigate the necessity for neuroimaging, shortening the diagnostic -and treatment- pathway. An up-to-date review of immunological test performance is however lacking.

METHODOLOGY/PRINCIPAL FINDINGS

Searches were performed in PubMed, EMBASE, Web of Science, and Scopus (up to January 2024), with included records fitting the review scope, i.e. accuracy evaluation of an antibody-/or antigen-detecting immunological test, using serum or urine of humans confirmed via reference standard (i.e. neuroimaging or surgery/biopsy). Record data was assessed, with classification of descriptive data on cyst localization and stage according to a developed confidence scale, and with selection of tests evaluated on a sufficiently high sample size. A QUADAS-2 risk of bias assessment was performed. After screening, 169 records were included for data collection, with 53 records-corresponding to 123 tests- selected for analysis. Absence of data and large data heterogeneity complicated result interpretation. The lentil lectin-bound glycoprotein enzyme-linked immunoelectrotranfser blot seems to fulfill high accuracy standards regarding detection of parenchymal active multiple cysts; also antigen-detecting tests on serum and urine performed well, additionally in detection of extraparenchymal neurocysticercosis. A novel multi-antigen print immunoassay is highly promising, with sensitivity for detection of extraparenchymal and parenchymal active single and multiple cysts of 100.0%, and specificity of 98.5%. Point-of-care tests showed promising results, however require further evaluation in targeted resource-poor settings.

CONCLUSIONS/SIGNIFICANCE

The review highlights the importance of transparent and unambiguous data reporting. With promising immunological tests in development, the challenge before usage in targeted settings will be to perform large-scale evaluations whilst holding into account both optimized test performance and ease of use. Accessibility to validated tests and feasibility of implementation should also be considered.

Consistent Measurement of Parasite-Specific Antigen Levels in Sera of Patients with Neurocysticercosis Using Two Different Monoclonal Antibody (mAb)-Based Enzyme-Linked Immunosorbent Assays

Monoclonal antibody (mAb)-based enzyme-linked immunosorbent assay (ELISA) is a complementary diagnosis technique for neurocysticercosis (NCC), which detects circulating parasite antigen (Ag) indicative of viable infection and Ag levels that correlate well with the parasite burden. In this study, we compared the performance of two Ag-ELISA techniques for the detection of NCC. We assessed the agreement between our in-house TsW8/TsW5 Ag-ELISA and the widely used B158/B60 Ag-ELISA for measuring T. solium antigen levels in the sera from 113 patients with calcified, parenchymal, and subarachnoid NCC. Concordance was demonstrated evaluating the limits of agreement (LoAs) stratified by the type of NCC. Both ELISA's detected 47/48 (97.8%) subarachnoid NCC cases. In parenchymal and calcified NCC, the B158/B60 Ag-ELISA detected 19/24 (79.2%) and 18/41 (43.9%) cases, while the TsW8/TsW5 Ag-ELISA detected 21/24 (87.5%) and 13/41 (31.7%), respectively. Parenchymal and calcified NCC obtained a perfect agreement (100%), indicating that all sample results were within the predicted LoA, while for subarachnoid NCC, the agreement was 89.6%. The high concordance between the assays was confirmed by Lin's concordance coefficient (LCC = 0.97). Patients with viable parenchymal NCC (LCC = 0.95) obtained the highest concordance between assays, followed by subarachnoid NCC (LCC = 0.93) and calcified NCC (LCC = 0.92). The TsW8/TsW5 Ag-ELISA and B158/B60 Ag-ELISA showed high Ag measurement correlations across diverse types of NCC.

Neurocysticercosis: A Review into Treatment Options, Indications, and Their Efficacy

Neurocysticercosis, due to the localization of Taenia solium larvae in the Central Nervous System, is a neglected tropical disease still endemic in much of Latin America, Asia and sub-Saharan Africa. The therapeutic management of NC has gradually improved with the establishment of neuroimaging studies (CT and MRI) in endemic countries and with the demonstration of the efficacy of albendazole and praziquantel in the 1980s. But the morbidity and mortality of this preventable disease remain an unacceptable fact. In this scoping review, we will revise the different treatment options and their indications.

Global variation in force-of-infection trends for human Taenia solium taeniasis/cysticercosis

Infection by Taenia solium poses a major burden across endemic countries. The World Health Organization (WHO) 2021–2030 Neglected Tropical Diseases roadmap has proposed that 30% of endemic countries achieve intensified T. solium control in hyperendemic areas by 2030. Understanding geographical variation in age-prevalence profiles and force-of-infection (FoI) estimates will inform intervention designs across settings. Human taeniasis (HTT) and human cysticercosis (HCC) age-prevalence data from 16 studies in Latin America, Africa, and Asia were extracted through a systematic review. Catalytic models, incorporating diagnostic performance uncertainty, were fitted to the data using Bayesian methods, to estimate rates of antibody (Ab)-seroconversion, infection acquisition and Ab-seroreversion or infection loss. HCC FoI and Ab-seroreversion rates were also estimated across 23 departments in Colombia from 28,100 individuals. Across settings, there was extensive variation in all-ages seroprevalence. Evidence for Ab-seroreversion or infection loss was found in most settings for both HTT and HCC and for HCC Ab-seroreversion in Colombia. The average duration until humans became Ab-seropositive/infected decreased as all-age (sero)prevalence increased. There was no clear relationship between the average duration humans remain Ab-seropositive and all-age seroprevalence. Marked geographical heterogeneity in T. solium transmission rates indicate the need for setting-specific intervention strategies to achieve the WHO goals.

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.

A recombinant monoclonal-based Taenia antigen assay that reflects disease activity in extra-parenchymal neurocysticercosis

BACKGROUND

Antigen tests for diagnosis and disease monitoring in some types of neurocysticercosis (NCC) are useful but access to testing has been limited by availability of proprietary reagents and/or kits.

METHODS/PRINCIPAL FINDINGS

Three previously identified IgM-secreting hybridomas whose IgM products demonstrated specificity to Taenia solium underwent variable heavy and light chain sequencing and isotype conversion to mouse IgG. Screening of these recombinantly expressed IgG anti-Ts hybridomas, identified one (TsG10) with the highest affinity to crude Taenia antigen. TsG10 was then used as a capture antibody in a sandwich antigen detection immunoassay in combination with either a high titer polyclonal anti-Ts antibody or with biotinylated TsG10 (termed TsG10*bt). Using serum, plasma, and CSF samples from patients with active NCC and those from NCC-uninfected patients, ROC curve analyses demonstrated that the TsG10-TsG10-*bt assay achieved a 98% sensitivity and 100% specificity in detecting samples known to be antigen positive and outperformed the polyclonal based assay (sensitivity of 93% with 100% specificity). By comparing levels of Ts antigen (Ag) in paired CSF (n = 10) or plasma/serum (n = 19) samples from well-characterized patients with extra-parenchymal NCC early in infection and at the time of definitive cure, all but 2 (1 from CSF and 1 from plasma) became undetectable. There was a high degree of correlation (r = 0.98) between the Ag levels detected by this new assay and levels found by a commercial assay. Pilot studies indicate that this antigen can be detected in the urine of patients with active NCC.

CONCLUSIONS/SIGNIFICANCE

A newly developed recombinant monoclonal antibody-based Ts Ag detection immunoassay is extremely sensitive in the detection of extra-parenchymal NCC and can be used to monitor the success of treatment in the CSF, serum/plasma and urine. The ability to produce recombinant TsG10 at scale should enable use of this antigen detection immunoassay wherever NCC is endemic.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov Identifiers: NCT00001205 - & NCT00001645.

Evaluation of recombinant glutathione transferase 26 kDa, thioredoxin-1, and endophilin B1 of Taenia solium in the diagnosis of human neurocysticercosis

Neurocysticercosis caused by Taenia solium larvae is a neglected disease that persists in several countries, including Mexico, and causes a high disability-adjusted life year burden. Neuroimaging tools such as computed tomography and magnetic resonance imaging are the most efficient for its detection, but low availability and high costs in most endemic regions limit their use. Serological methods such as lentil lectin-purified glycoprotein enzyme-linked immunoelectrotransfer blot antibody detection and monoclonal antibody-based enzyme-linked immunosorbent assays for HP10 antigen detection have been useful in supporting the diagnosis of this disease. We evaluated three T. solium recombinant antigens: glutathione transferase of 26 kDa (Ts26GST); thioredoxin-1 (TsTrx-1), and endophilin B1 (TsMEndoB1) by EITB. These are antigenic proteins antigenic, abundant in excretion/secretion products of the parasite, and do not cross-react with homologous host proteins. Ts26GST and TsTrx-1 showed sensitivity of 79 and 88%, specificity of 86 and 97%, PPV of 83 and 97% and NPV of 82 and 91%, respectively, for neurocysticercosis diagnosis. The recombinant antigens allowed the diagnosis of 70% (Ts26GST) and 80% (TsTrx-1) of patients having only one cysticercus. Further studies on specific regions of these proteins could improve T. solium diagnostics.

Evaluation of an Antibody Detecting Point of Care Test for Diagnosis of Taenia solium Cysticercosis in a Zambian Rural Community: A Prospective Diagnostic Accuracy Study

The lack of cheap, easy-to-use, rapid diagnostic tests has led to the development of several rapid diagnostic tests for cysticercosis. The new prototype two-strip, Taenia solium point of care test (TS POC) detects antibodies against taeniosis (TS POC T) and cysticercosis (TS POC CC). This study evaluated the diagnostic performance of the TS POC CC in the Sinda district in eastern Zambia. A sample of 1254 participants was recruited and tested with the TS POC. Out of the 1249 participants with a valid TS POC result, 177 (14%) tested positive while 1072 (86%) tested negative. All individuals with a positive TS POC and a subset of negative TS POC participants were selected for serum sampling, and were subjected to the recombinant glycoprotein T24H enzyme-linked immunoelectrotransfer blot (rT24H EITB) and the serum B60/158 (serum Ag) enzyme-linked immunosorbent assay (Ag ELISA). Performance characteristics were estimated using a Bayesian approach with probabilistic constraints. Based on 255 complete cases, the estimated sensitivity and specificity of the TS POC CC test were 35% (95% CI: 14–63%) and 87% (95% CI: 83–90%), respectively. The diagnostic performance needs to be improved, possibly by titrating antigen and other reagents’ concentration in the strip to produce a performance similar to existing cysticercosis tests such as the rT24H EITB.

Subarachnoid Neurocysticercosis Presenting as a New-Onset Seizure in an Immigrant From Guatemala

Subarachnoid involvement is a rare but severe form of neurocysticercosis (NCC), leading to serious complications if not recognized and treated appropriately. Imaging of the brain usually involves computed tomography and/or magnetic resonance image (MRI) of the brain, both of which can lead to a diagnosis of NCC. We present a 20-year-old female with no significant past medical history presenting with a new-onset seizure whose clinical treatment was significantly altered when subarachnoid involvement was identified. This case highlights the importance of brain MRI in recognizing subarachnoid disease, an important subset of NCC disease presentation.

Subarachnoid neurocysticercosis: emerging concepts and treatment

PURPOSE OF REVIEW

Subarachnoid neurocysticercosis (SUBNCC) is caused by a morphologically unique proliferative form of Taenia solium involving the subarachnoid spaces. Prolonged therapy based upon the pathophysiology of SUBNCC and long-term follow-up have shed light on the course of disease and led to highly improved outcomes.

RECENT FINDINGS

SUBNCC has a prolonged incubation period of between 10 and 25 years characterized by cyst proliferation and growth and invasion of contiguous spaces leading to mass effect (Stage 1). With induction of the host-immune responses, cysts degenerate leading to a predominately inflammatory arachnoiditis (Stage 2) causing hydrocephalus, infarcts, and other inflammatory based neurological manifestations. Inactive disease (Stage 3) may occur naturally but mostly is a result of successful treatment, which generally requires prolonged intensive anthelminthic and antiinflammatory treatments. Cerebral spinal fluid cestode antigen or cestode DNA falling to nondetectable levels predicts effective treatment. Prolonged treatment with extended follow-up has resulted in moderate disability and no mortality. Repeated short intensive 8-14-day courses of treatment are also used, but long-term outcomes and safety using this strategy are not reported.

SUMMARY

SUBNCC gives rise to a chronic arachnoiditis. Its unique ability to proliferate and induce inflammatory responses requires long-term anthelmintic and antiinflammatory medications.

Inflammation in neurocysticercosis: clinical relevance and impact on treatment decisions

INTRODUCTION

Neurocysticercosis is caused by the localization of Taenia solium larvae in the central nervous system. The disease remains endemic in most countries of Latin America, Asia and Africa. While major improvements have been made in its diagnosis and treatment, uncertainties persist regarding the clinical implications and treatment of the inflammatory reaction associated with the disease.

AREAS COVERED

In this review, based on PubMed searches, the authors describe the characteristics of the immune-inflammatory response in patients with neurocysticercosis, its clinical implications and the treatment currently administered. The dual role of inflammation (participating in both, the death of the parasite, and the precipitation of serious complications) is discussed. New therapeutic strategies of potential interest are presented.

EXPERT OPINION

Inflammatory reaction is the main pathogenic mechanism associated to neurocysticercosis. Its management is mainly based on corticosteroids administration. This strategy had improved prognostic of patients as it allows for the control of most of the inflammatory complications. On the other side, it might be involved in the persistence of parasites in some patients, despite cysticidal treatment, due to its immunosuppressive properties. New strategies are needed to improve therapeutical management, particularly in the severest presentations.

Taenia solium taeniasis/cysticercosis: From parasite biology and immunology to diagnosis and control

Infection with the pork tapeworm (Taenia solium) is responsible for a substantial global burden of disease, not only restricted to its impact on human health, but also resulting in a considerable economic burden to smallholder pig farmers due to pig cysticercosis infection. The life-cycle, parasitology and immunology of T. solium are complex, involving pigs (the intermediate host, harbouring the larval metacestode stage), humans (the definitive host, harbouring the adult tapeworm, in addition to acting as accidental intermediate hosts) and the environment (the source of infection with eggs/proglottids). We review the parasitology, immunology, and epidemiology of the infection associated with each of the T. solium life-cycle stages, including the pre-adult/adult tapeworm responsible for human taeniasis; post-oncosphere and cysticercus associated with porcine and human cysticercosis, and the biological characteristics of eggs in the environment. We discuss the burden associated, in endemic settings, with neurocysticercosis (NCC) in humans, and the broader cross-sectoral economic impact associated both with NCC and porcine cysticercosis, the latter impacting food-value chains. Existing tools for diagnostics and control interventions that target different stages of the T. solium transmission cycle are reviewed and their limitations discussed. Currently, no national T. solium control programmes have been established in endemic areas, with further work required to identify optimal strategies according to epidemiological setting. There is increasing evidence suggesting that cross-sectoral interventions which target the parasite in both the human and pig host provide the most effective approaches for achieving control and ultimately elimination. We discuss future avenues for research on T. solium to support the attainment of the goals proposed in the revised World Health Organisation neglected tropical diseases roadmap for 2021-2030 adopted at the 73rd World Health Assembly in November 2020.

Diagnostic value of glycoprotein band patterns of three serologic enzyme-linked immunoelectrotransfer blot assays for neurocysticercosis

The enzyme-linked immunoelectrotransfer blot (EITB) assay to detect antibodies in serum is a complementary tool for the diagnosis of neurocysticercosis (NCC). Presence of at least one glycoprotein band corresponding to a Taenia solium (T. solium) antigen indicates a positive result; however, EITB assays have multiple glycoprotein bands, and previous work has suggested that band patterns may have additional diagnostic value. We included 58 participants with a definitive diagnosis of NCC who received care at the Instituto Nacional de Neurología y Neurocirugía in Mexico City. Three different EITB tests were applied to participants' serum samples (LDBio, France; US Centers for Disease Control and Prevention [CDC]; and Instituto de Diagnóstico y Referencia Epidemiológicos [InDRE]). There was substantial variability in specific glycoprotein band patterns among the three assays. However, in age- and sex-adjusted logistic regression models, the number of glycoprotein bands was positively associated with the presence of vesicular extraparenchymal cysts (InDRE adjusted odds ratio [aOR] 1.60 p < 0.001; CDC aOR 6.31 p < 0.001; LDBio aOR 2.45 p < 0.001) and negatively associated with the presence of calcified parenchymal cysts (InDRE aOR 0.63 p < 0.001; CDC aOR 0.25 p < 0.001; LDBio aOR 0.44 p < 0.001). In a sensitivity analysis also adjusting for cyst count, results were similar. In all three EITB serum antibody tests, the number of glycoprotein bands consistently predicted cyst stage and location, although magnitude of effect differed.

Natural History of Treated Subarachnoid Neurocysticercosis

Subarachnoid neurocysticercosis (SUBNCC) is usually caused by an aberrant proliferative form of Taenia solium causing mass effect and arachnoiditis. Thirty of 34 SUBNCC patients were treated with extended cysticidal and anti-inflammatory regimens and followed up a median of 4.2 years posttreatment (range: 15 for ≥ 4 years, 20 ≥ 2 years, 26 > 1 year, and 3 < 1 year). The median ages at the time of first symptom, diagnosis, and enrollment were 29.7, 35.6, and 37.9 years, respectively; 58.8% were male and 82.4% were Hispanic. The median time from immigration to symptoms (minimum incubation) was 10 years and the estimated true incubation period considerably greater. Fifty percent also had other forms of NCC. Common complications were hydrocephalus (56%), shunt placement (41%), infarcts (18%), and symptomatic spinal disease (15%). Thirty patients (88.2%) required prolonged treatment with albendazole (88.2%, median 0.55 year) and/or praziquantel (61.8%; median 0.96 year), corticosteroids (88.2%, median 1.09 years), methotrexate (50%, median 1.37 years), and etanercept (34.2%, median 0.81 year), which led to sustained inactive disease in 29/30 (96.7%) patients. Three were treated successfully for recurrences and one has continuing infection. Normalization of cerebral spinal fluid parameters and cestode antigen levels guided treatment decisions. All 15 patients with undetectable cestode antigen values have sustained inactive disease. There were no deaths and moderate morbidity posttreatment. Corticosteroid-related side effects were common, avascular necrosis of joints being the most serious (8/33, 24.2%). Prolonged cysticidal treatment and effective control of inflammation led to good clinical outcomes and sustained inactive disease which is likely curative.

Immunodiagnosis of human neurocysticercosis: comparative performance of serum diagnostic tests in Mexico

Immunodiagnosis has a supportive role in the diagnosis of neurocysticercosis (NCC). The aim of this study was to compare the validity of seven immunodiagnostic tests among serum samples from 58 patients with NCC, 26 patients with neurological diseases other than NCC, and 15 healthy controls. One test for viable parasite detection (HP10 antigen assay) and six for antibody detection were evaluated. For the entire sample, sensitivities ranged from 55.2% (NOVALISA) to 81.0% (enzyme-linked immunosorbent assay [ELISA] Taenia solium antibody), with the sensitivity of the latter test significantly higher than that of the in-house ELISA Taenia crassiceps, NOVALISA, enzyme-linked immunoelectrotransfer blot (EITB) CDC, and HP10. Overall, specificities were high, ranging from 85.4% (ELISA Ts) to 97.1% (NOVALISA), with no statistically significant differences. Detection of HP10 antigen was significantly associated with the presence of vesicular parasites. The simple and low-cost ELISA Taenia solium antibody Ab instead of EITB is recommended to support NCC diagnosis in both rural and hospital settings in Mexico.

Progress on the development of rapid diagnostic tests for foodborne neglected zoonotic helminthiases: A systematic review

BACKGROUND

Foodborne Neglected Zoonotic Helminths (FNZH) are parasites of both economic and public health importance. They include Taenia solium, Echinococcus granulosus sensu lato, Echinococcus multilocularis and Foodborne trematodes (FBT). FNZH are earmarked for major interventions for control, elimination and eradication. This systematic review highlights the progress towards development of rapid tests for the diagnosis of FNZH since 2010 when they were listed as neglected tropical diseases.

METHODOLOGY

A systematic search was conducted in three databases, World of Science, Embase and PubMed using the same search phrase. The search produced 480 hits. Three studies from back referencing were included. Only 22 of these met the inclusion criteria. Data was extracted from these and presented qualitatively.

RESULTS

Twenty-five rapid diagnostic tests were found to have been developed since 2010, eight for diagnosis of T. solium infections, eight for echinococcosis and nine for FBT infections. The rapid tests for diagnosing T. solium infections included six antibody detecting and two antigen detecting tests. They constitute a combination among them, with some tests providing qualitative, others quantitative results. Similarly, seven out of the eight rapid tests developed for Echinococcus infections were antibody detecting tests save for one loop mediated isothermal amplification test. All of them were qualitative tests. For FBT infections, nine rapid tests were described; two antibody and one nucleic acid detecting test for diagnosis of Fascioliasis; three nucleic acid detecting tests for Opisthorchiasis; one antibody detecting test for Paragonimiasis; and for Clonorchiasis, one antibody and one nucleic acid detecting test. The FBT infection rapid tests were all qualitative in nature. Most of these tests have not undergone field evaluation in endemic areas where they will be used most.

CONCLUSION

This review describes the development and evaluation of rapid diagnostic tests, while highlighting the need for in depth validations of the tools to determine how well they can perform in endemic areas.

Biological role of excretory-secretory proteins in endemic parasites of Latin America and the Caribbean

Neglected tropical diseases (NTDs) share certain traits: they are parasitic infections, prevailing in tropical environments and affecting marginalized sectors of the population. Six NTDs - ascariasis, cysticercosis, echinococcosis, hookworm infection, onchocerciasis and trichuriasis - all of them endemic in Latin America and the Caribbean (LAC), are analysed in this work. This review aims to discuss key information on the function of excretory/secretory (E/S) proteins from these parasites in their infectivity, pathogeny and diagnosis. The modulation of the host immune system to favour the permanence and survival of the parasite is also discussed. An updated knowledge on the function of E/S molecules in endemic parasitoses in LAC may lead to new approaches for the clinical management and diagnosis of these diseases. In turn, this could allow us to optimize their treatment and make it more affordable - a relevant goal given the economic constraints that the region is facing.

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.

Reciprocal contribution of clinical studies and the HP10 antigen ELISA for the diagnosis of extraparenchymal neurocysticercosis

To evaluate diagnosis of active neurocysticercosis, paired cerebral spinal fluid (CSF) and serum samples from 24 neurocysticercosis (NCC) patients and 17 control neurological patients were assayed in the HP10 Taenia antigen (Ag) ELISA. The CSF samples were also tested with an HP10 Lateral Flow Assay (LFA). The HP10 Ag was detected by ELISA in the CSF of 5/5 patients with Definitive extraparenchymal NCC, and in 4/5 of the corresponding sera. In the Definitive parenchymal group, on the other hand, the HP10 Ag was absent in 2/3 CSF (with a very low value in the one positive sample) and all the corresponding serum samples. Samples of CSF from 4/7 patients in the Probable parenchymal group, were also significantly HP10 Ag positive, suggesting the presence of extraparenchymal cysts not identified by the imaging studies. With the possible exception of one patient, the corresponding serum samples of the Probable parenchymal NCC group, were all HP10 Ag negative. Samples of CSF from 9 NCC patients diagnosed with Mixed parenchymal and extraparenchymal NCC were all significantly HP10 Ag positive, confirming the presence of extraparenchymal cysts, with only 7/9 of the corresponding serum samples being HP10 positive. Thus detection of the HP10 Ag indicates extraparenchymal and not parenchymal cyst localization and is more sensitive with CSF than serum. Three neurological patients clinically diagnosed as subarachnoid cyst, hydrocephalus and tuberculoma, respectively, were clearly positive for HP10 Ag. Of these, two were confirmed as NCC by subsequent imaging; the third died prior to further examination. Thus, a total of 8 patients had their clinical diagnosis questioned. Finally, there was good agreement between the HP10 Ag ELISA and LFA with CSF samples giving an optical density ≥0.4 in the ELISA assay. In conclusion, the HP10 Ag assay should provide a valuable and reciprocal tool in the clinical diagnosis and follow up of extraparenchymal NCC.

A lateral flow assay (LFA) for the rapid detection of extraparenchymal neurocysticercosis using cerebrospinal fluid

A lateral flow assay (LFA) for the diagnosis and monitoring of extraparenchymal neurocysticercosis, has been developed. The assay is based on the use of the monoclonal antibody HP10, and when applied to cerebrospinal fluid, correctly identified 34 cases of active extraparenchymal neurocysticercosis, but was negative with 26 samples from treated and cured neurocysticercosis patients and with 20 samples from unrelated neurological diseases. There was complete agreement between the HP10 Ag-ELISA results and the HP10-LFA. The HP10-LFA thus has utility for diagnosis and treatment of extraparenchymal neurocysticercosis, frequently a more dangerous form of the infection.

Anti-Taenia solium monoclonal antibodies for the detection of parasite antigens in body fluids from patients with neurocysticercosis

Neurocysticercosis (NCC), an infection of the brain by Taenia solium (Ts) cysts, is the most common cause of adult-onset epilepsy in developing countries. Serological testing consists primarily of varying methods to detect antibodies in body fluids and more recently antigen (Ag) detection assays to identify individuals or animals with viable parasites. Antigen assays currently in use employ monoclonal antibodies (mAbs) raised against T. saginata, which have known cross reactivity to animal cestodes but are highly specific in human samples. We produced, characterized and tested 21 mAbs raised against T. solium whole cyst antigens, vesicular fluid or excretory secretory products. Reactivity of the TsmAbs against specific cyst structures was determined using immunofluorescence and immunohistochemistry on histological sections of Ts muscle cysts. Four TsmAbs reacted to vesicular space alone, 9 to the neck and cyst wall, one to the neck and vesicular space and 7 to the neck, cyst wall and vesicular space. An in-house ELISA assay to detect circulating Ts antigen, using the TsmAbs as capture antibodies and a rabbit polyclonal anti-Ts whole cyst antibody as a detector antibody demonstrated that eight of the 21 TsmAbs detected antigens in known NCC-positive human sera and three of these also in urine samples. Reactivity was expressed as normalized ratios of optical densities (OD positive control/OD negative control). Three TsmAbs had ratios >10 and five between 2 and 10. The TsmAbs have potential utility for the diagnosis and post-treatment monitoring of patients with viable NCC infections.

The Influence of Socio-economic, Behavioural and Environmental Factors on Taenia spp. Transmission in Western Kenya: Evidence from a Cross-Sectional Survey in Humans and Pigs

Taenia spp. infections, particularly cysticercosis, cause considerable health impacts in endemic countries. Despite previous evidence of spatial clustering in cysticercosis and the role of environmental factors (e.g. temperature and humidity) in the survival of eggs, little research has explored these aspects of Taenia spp.

EPIDEMIOLOGY

In addition, there are significant gaps in our understanding of risk factors for infection in humans and pigs. This study aimed to assess the influence of socio-economic, behavioural and environmental variables on human and porcine cysticercosis. A cross-sectional survey for human taeniasis (T. solium and T. saginata), human cysticercosis (T. solium) and pig cysticercosis (T. solium) in 416 households in western Kenya was carried out. These data were linked to questionnaire responses and environmental datasets. Multi-level regression was used to examine the relationships between covariates and human and porcine cysticercosis. The HP10 Ag-ELISA sero-prevalence (suggestive of cysticercosis) was 6.6% for humans (95% CI 5.6%-7.7%), and 17.2% for pigs (95% CI 10.2%-26.4%). Human taeniasis prevalence, based on direct microscopic observation of Taenia spp. eggs (i.e. via microscopy results only) was 0.2% (95% CI 0.05%-0.5%). Presence of Taenia spp. antigen in both humans and pigs was significantly associated with a range of factors, including positive correlations with land cover. The presence of HP10 antigen in humans was correlated (non-linearly) with the proportion of land within a 1 km buffer that was flooding agricultural land and grassland (odds ratio [OR] = 1.09 and 0.998; p = 0.03 and 0.03 for the linear and quadratic terms respectively), gender (OR = 0.58 for males compared to females, p = 0.02), level of education (OR = 0.62 for primary level education versus no formal education, p = 0.09), use of well water for drinking (OR = 2.76 for those who use well water versus those who do not, p = 0.02) and precipitation (OR = 0.998, p = 0.02). Presence of Taenia spp. antigen in pigs was significantly correlated with gender and breeding status of the pig (OR = 10.35 for breeding sows compared to boars, p = 0.01), and the proportion of land within a 1 km buffer that was flooding agricultural land and grassland (OR = 1.04, p = 0.004). These results highlight the role of multiple socio-economic, behavioural and environmental factors in Taenia spp. transmission patterns. Environmental contamination with Taenia spp. eggs is a key issue, with landscape factors influencing presence of Taenia spp. antigens in both pigs and humans.

Relevance of 3D magnetic resonance imaging sequences in diagnosing basal subarachnoid neurocysticercosis

Imagenological diagnosis of subarachnoid neurocysticercosis is usually difficult when classical magnetic resonance imaging (MRI) sequences are used. The purpose of this study was to evaluate the advantages of 3D MRI sequences (Fast Imaging Employing Steady-state Acquisition (FIESTA) and Spoiled Gradient Recalled Echo (SPGR)) with respect to classical sequences (Fluid Attenuation Inversion Recovery (FLAIR) and T1) in visualizing Taenia solium cyst in these locations. Forty-seven T. solium cysts located in the basal cisterns of the subarachnoid space were diagnosed in eighteen Mexican patients. A pre-treatment MRI was performed on all patients, and all four sequences (FIESTA, FLAIR, T1 SPGR, and T2) were evaluated independently by two neuroradiologists. The sensitivity of each sequence to detect the parasite membrane and scolex was evaluated, along with its capacity to detect differences in signal intensity between cerebrospinal fluid (CSF) and cysts. FIESTA sequences allowed the visualization of cyst membrane in 87.2% of the parasites evaluated, FLAIR in 38.3%, SPGR in 23.4%, and T2 in 17.0%. The superiority of FIESTA sequences over the other three imaging methods was statistically significant (P<0.001). Scolices were detected by FIESTA twice as much as the other sequences did, although this difference was not significant (P>0.05). Differences in signal intensity between CSF and parasite cysts were significant in FIESTA (P<0.0001), SPGR (P<0.0001), and FLAIR (P=0.005) sequences. For the first time, the usefulness of 3D MRI sequences to diagnose T. solium cysts located in the basal cisterns of the subarachnoid space was demonstrated. The routine use of these sequences could favor an earlier diagnosis and greatly improve the prognosis of patients affected by this severe form of the disease.

Successful Antiparasitic Treatment for Cysticercosis is Associated with a Fast and Marked Reduction of Circulating Antigen Levels in a Naturally Infected Pig Model

Taenia solium cysticercosis is a common parasitic infection of humans and pigs. We evaluated the posttreatment evolution of circulating parasite-specific antigen titers in 693 consecutive blood samples from 50 naturally infected cysticercotic pigs, which received different regimes of antiparasitic drugs (N = 39, 7 groups), prednisone (N = 5), or controls (N = 6). Samples were collected from baseline to week 10 after treatment, when pigs were euthanized and carefully dissected at necropsy. Antigen levels decreased proportionally to the efficacy of treatment and correlated with the remaining viable cysts at necropsy (Pearson's p = 0.67, P = 0.000). A decrease of 5 times in antigen levels (logarithmic scale) compared with baseline was found in 20/26 pigs free of cysts at necropsy, compared with 1/24 of those who had persisting viable cysts (odds ratio [OR] = 76.7, 95% confidence interval [CI] = 8.1-3308.6, P < 0.001). Antigen monitoring reflects the course of infection in the pig. If a similar correlation exists in infected humans, this assay may provide a minimally invasive and easy monitoring assay to assess disease evolution and efficacy of antiparasitic treatment in human neurocysticercosis.

Taenia solium Human Cysticercosis: A Systematic Review of Sero-epidemiological Data from Endemic Zones around the World

Background

Taenia solium cysticercosis is a zoonotic neglected disease responsible for severe health disorders such as seizures and death. Understanding the epidemiology of human cysticercosis (HCC) in endemic regions will help to expose critical information about the transmission of the disease, which could be used to design efficient control programs. This review gathered serological data on apparent prevalence of T. solium circulating antigens and/or seroprevalence of T. solium antibodies, apparent prevalence of human taeniasis and risk factors for HCC from endemic communities in order to understand the differences in exposure to the parasite and active infections with T. solium metacestodes in endemic areas around the world.

Methods

Three databases were used to search sero-epidemiological data from community-based studies conducted between 1989 and 2014 in cysticercosis endemic communities worldwide. The search focused on data obtained from T. solium circulating antigen detection by monoclonal antibody-based sandwich ELISA and/or T. solium antibody seroprevalence determined by Enzyme-linked Immunoelectrotransfer Blot (EITB). A meta-analysis was performed per continent.

Principal Findings

A total of 39,271 participants from 19 countries, described in 37 articles were studied. The estimates for the prevalence of circulating T. solium antigens for Africa, Latin America and Asia were: 7.30% (95% CI [4.23–12.31]), 4.08% (95% CI [2.77–5.95]) and 3.98% (95% CI [2.81–5.61]), respectively. Seroprevalence estimates of T. solium antibodies were 17.37% (95% CI [3.33–56.20]), 13.03% (95% CI [9.95–16.88]) and 15.68% (95% CI [10.25–23.24]) respectively. Taeniasis reported prevalences ranged from 0 (95% CI [0.00–1.62]) to 17.25% (95% CI [14.55–20.23]).

Significance

A significant variation in the sero-epidemiological data was observed within each continent, with African countries reporting the highest apparent prevalences of active infections. Intrinsic factors in the human host such as age and immunity were main determinants for the occurrence of infections, while exposure was mostly related to environmental factors which varied from community to community.

Human cysticercosis is a neglected zoonotic disease caused by the larval stage of the parasite Taenia solium. This disease is responsible for severe health disorders such as seizures, and in some cases even death. T. solium cysticercosis is endemic in countries in Africa, Latin America and Asia where conditions such as inadequate hygiene, poor sanitary conditions, open defecation, free roaming pigs and poverty permit the transmission of the disease. Diagnostic tools are capable of detecting exposure to eggs and infection levels in a population through antibody and antigen detection, respectively. This review focused on gathering epidemiological data from endemic communities in Africa, Latin America and Asia in order to understand the causes of the observed variations in exposure/infection patterns in endemic regions. Similar antibody seroprevalences were observed worldwide while infection prevalences varied significantly within each region. Intrinsic factors such as age and immunity were determining factors for the occurrence of infections, while exposure was related to environmental factors which varied from region to region. Understanding the epidemiology of cysticercosis in endemic regions will help expose information on the transmission, which could in turn be used to design appropriate control programs.

Extraparenchymal (Racemose) Neurocysticercosis and Its Multitude Manifestations: A Comprehensive Review

Neurocysticercosis is an infection of the central nervous system caused by the larval form of the pork tapeworm Taenia solium. In the brain it occurs in two forms: parenchymal and extraparenchymal or racemose cysts. The clinical presentation of racemose cysts is pleomorphic, and is quite different from parenchymal cysticercosis. The clinical diagnosis of racemose cysts is quite challenging, with neuroimaging being the mainstay. However, the advent of newer brain imaging modalities has made a more accurate diagnosis possible. The primary focus of this article is racemose neurocysticercosis and its multitude manifestations, and includes a discussion of the newer diagnostic modalities and treatment options.

Comparative Study of Paired Serum and Cerebrospinal Fluid Samples from Neurocysticercosis Patients for the Detection of Specific Antibody to Taenia solium Immunodiagnostic Antigen

Neurocysticercosis (NCC) is an important disease of the central nervous system caused by infection with Taenia solium metacestodes. In addition to the clinical findings and the imaging analysis, the results of immunological tests are informative for the diagnosis of NCC. To compare the usefulness of serum and cerebrospinal fluid (CSF) samples for antibody detection, paired serum and CSF samples from patients with NCC and other neurological diseases were examined by an enzyme-linked immunosorbent assay with low-molecular-weight antigens purified from T. solium cyst fluid in a blinded fashion. The sensitivity of both serum and CSF samples was 25.0% in inactive NCC cases (n = 4) and 90.9% in active NCC cases (n = 33), and the specificity of serum and CSF was 100% and 95.8%, respectively. When the serum and CSF samples were combined, the sensitivity in active NCC cases became 100%. There was no difference in test performance between serum and CSF samples. Based on these results, we recommend the detection of specific antibodies in serum for the diagnosis of active NCC because of the ease of collection. When the antibody test is negative, however, CSF should be used to confirm NCC and to rule out other medical disorders of the central nervous system. Antibody detection test using only serum or CSF has a limited diagnostic value and cannot be recommended for the diagnosis of suspected inactive NCC cases.

Genome analysis of Excretory/Secretory proteins in Taenia solium reveals their Abundance of Antigenic Regions (AAR)

Excretory/Secretory (ES) proteins play an important role in the host-parasite interactions. Experimental identification of ES proteins is time-consuming and expensive. Alternative bioinformatics approaches are cost-effective and can be used to prioritize the experimental analysis of therapeutic targets for parasitic diseases. Here we predicted and functionally annotated the ES proteins in T. solium genome using an integration of bioinformatics tools. Additionally, we developed a novel measurement to evaluate the potential antigenicity of T. solium secretome using sequence length and number of antigenic regions of ES proteins. This measurement was formalized as the Abundance of Antigenic Regions (AAR) value. AAR value for secretome showed a similar value to that obtained for a set of experimentally determined antigenic proteins and was different to the calculated value for the non-ES proteins of T. solium genome. Furthermore, we calculated the AAR values for known helminth secretomes and they were similar to that obtained for T. solium. The results reveal the utility of AAR value as a novel genomic measurement to evaluate the potential antigenicity of secretomes. This comprehensive analysis of T. solium secretome provides functional information for future experimental studies, including the identification of novel ES proteins of therapeutic, diagnosis and immunological interest.

Neurocysticercosis: an update

Neurocysticercosis (NCC) is the most common helminthic disease of the nervous system in humans and a major cause of acquired epilepsy worldwide. The presentation of the disease is dependent on both the immunological response of the host against the parasite as well as the location of the encysted organisms within the central nervous system (CNS). The principles of management utilized for intraparenchymal disease cannot be applied to extraparenchymal NCC. An advance in management of intraparenchymal NCC, the most common form encountered by physicians, is the use of both albendazole and praziquantel as a treatment strategy. Patients with subarachnoid NCC (SANCC) require months of treatment with both an antiparasitic agent and steroids to avoid complications such as hydrocephalus and vascular events during treatment. The determinants of successful treatment in SANCC have not been established, but response to therapy can be determined by evaluating several endpoints related to disease evolution including radiographic changes, serum antigen, and CSF antigen. Intraventricular NCC is primarily a surgical disease and data supports minimally invasive endoscopic removal of cysts in many of these patients. NCC is increasingly recognized in non-endemic countries due to increased immigration making it important for physicians to become familiar with the management of this disease.

Pediatric neurocysticercosis: usefulness of antibody response in cysticidal treatment follow-up

Serum and urine samples were collected from 33 NCC patients before the albendazole treatment, 3-6 and 12 months PT. At 3 months PT, 24 (72.7%) patients had no detectable CT/MRI lesions and 9 (27.2%) patients had persistent lesions. Antibody response to crude soluble extract (CSE), excretory secretory (ES), and lower molecular mass (LMM) (10-30 KDa) antigenic fraction of T. solium cysticerci was detected in serum and urine samples by ELISA. Before the treatment, out of 33 NCC children, 14 (42.4%), 22 (66.6%), and 11 (33.3%) serum samples were found positive with the use of CSE, ES, and LMM antigen, respectively. At 3-6 months PT, positivity rate was 5 (15.1%), 2 (6%), and 4 (12.1%) and at 12 months PT, positivity rate was 5 (15.1%), 0, and 3 (9%) with the use of CSE, ES, and LMM antigen, respectively. There was no significant difference in the positivity with the use of three antigens in pretreatment and PT urine samples. The study suggests that the use of ES antigen to detect antibody in serum samples may serve better purpose to evaluate the therapeutic response in patients with NCC.

Diagnostic criteria for neurocysticercosis, revisited

Diagnosis of neurocysticercosis (NCC) can be a challenge. Clinical manifestations are non-specific, most neuroimaging findings are non-pathognomonic, and some serologic tests have low sensitivity or specificity. A set of diagnostic criteria was proposed in 2001 to avoid the over diagnosis of NCC that occurs in epidemiologic surveys, and to help clinicians evaluating patients with suspected NCC. The set included four stratified categories of criteria, including: (1) absolute: histological demonstration of cysticerci, cystic lesions showing the scolex on neuroimaging studies, and direct visualization of subretinal parasites by fundoscopic examination; (2) major: lesions highly suggestive of NCC on neuroimaging studies, positive serum enzyme-linked immunoelectrotransfer blot (EITB) for the detection of anticysticercal antibodies, resolution of intracranial cystic lesions after cysticidal drug therapy, and spontaneous resolution of single enhancing lesions; (3) minor: lesions compatible with NCC on neuroimaging studies, suggestive clinical manifestations, positive cerebrospinal fluid (CSF) ELISA for detection of anticysticercal antibodies or cysticercal antigens, and cysticercosis outside the nervous system; and (4) epidemiological: evidence of a household contact with Taenia solium infection, individuals coming from or living in cysticercosis endemic areas, and history of travel to disease-endemic areas. Interpretation of these criteria permits two degrees of diagnostic certainty: (1) definitive diagnosis, in patients who have one absolute criterion or in those who have two major plus one minor and one epidemiological criteria; and (2) probable diagnosis, in patients who have one major plus two minor criteria, in those who have one major plus one minor and one epidemiological criteria, and in those who have three minor plus one epidemiological criteria. After 10 years of usage, this set has been proved useful in both, field studies, and hospital settings. Recent advances in neuroimaging and immune diagnostic methods have enhanced its accuracy for the diagnosis of NCC.

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.

Human neurocysticercosis: immunological features involved in the host's susceptibility to become infected and to develop disease

Human neurocysticercosis (NC) is a clinically and radiologically heterogeneous disease caused by the establishment of Taenia solium larvae in the central nervous system. Herein, the immunological and endocrinological features involved in resistance to infection and severe forms of the disease are reviewed, and their clinical relevance is discussed.

Neurocysticercosis: HP10 antigen detection is useful for the follow-up of the severe patients

BACKGROUND

The most severe clinical form of neurocysticercosis (NC) occurs when cysticerci are located in the subarachnoid space at the base of the brain (SaB). The diagnosis, monitoring and treatment of NC-SaB, constitutes a severe clinical challenge. Herein we evaluate the potential of the HP10 antigen detection enzyme-linked immunosorbent assay (HP10 Ag-ELISA) in the long term follow-up of NC-SaB cases. Assay performance was compared with that of Magnetic Resonance Imaging (MRI). In addition, the robustness of the HP10 Ag-ELISA was evaluated independently at two different institutions.

METHODOLOGY/PRINCIPAL FINDINGS

A double-blind prospective cohort trial was conducted involving 38 NC-SaB cases and a total of 108 paired serum and cerebrospinal fluid (CSF) samples taken at intervals of 4 to 8 months for up to 43 months. At each medical visit, results of sera and CSF HP10 Ag-ELISA and MRI obtained at last visit were compared and their accuracy was evaluated retrospectively, considering radiological evolution between appointments. In the long-term follow-up study, HP10 Ag-ELISA had a better agreement than MRI with retrospective radiological evaluation. High reproducibility of HP10 Ag-ELISA between laboratories was also demonstrated.

CONCLUSIONS

Results reported in this study establish for the first time the usefulness of the comparatively low cost HP10 Ag-ELISA for long term follow-up of NC-SaB patients.

Added value of antigen ELISA in the diagnosis of neurocysticercosis in resource poor settings

Background

Neurocysticercosis (NCC) is the most common cause of acquired epilepsy in Taenia solium endemic areas, primarily situated in low-income countries. Diagnosis is largely based upon the “Del Brutto diagnostic criteria” using the definitive/probable/no NCC diagnosis approach. Neuroimaging and specific T. solium cysticercosis antibody detection results are at the mainstay of this diagnosis, while antigen detection in serum has never been included. This study aimed at evaluating the addition of antigen detection as a major diagnostic criterion, especially in areas where neuroimaging is absent.

Methods

The B158/B60 monoclonal antibody-based enzyme-linked immunosorbent assay (ELISA) for the detection of circulating cysticercus antigen was carried out retrospectively on serum samples collected during a hospital-based study from 83 people with epilepsy (PWE) in an endemic area.

Results

The addition of antigen results as a major criterion allowed the correct diagnosis of definitive NCC in 10 out of 17 patients as opposed to 0/17 without antigen results in the absence of neuroimaging. A sensitivity of 100% and a specificity of 84% were determined for the diagnosis of active NCC using antigen ELISA. While the use of a higher cutoff improves the specificity of the test to 96%, it decreases its sensitivity to 83%.

Conclusions

In areas where neuroimaging is absent, NCC diagnosis according to the existing criteria is problematic. Taking into account its limitations for diagnosis of inactive NCC, antigen detection can be of added value for diagnosing NCC in PWE by supporting diagnostic and treatment decisions. Therefore, we recommend a revision of the “Del Brutto diagnostic criteria” for use in resource poor areas and suggest the inclusion of serum antigen detection as a major criterion.

Neurocysticercosis is a parasitic infection of the central nervous system and a common cause of epilepsy in Taenia solium cysticercosis endemic countries. According to the current diagnostic criteria proposed by Del Brutto and colleagues, the diagnosis of neurocysticercosis is mainly based on neuroimaging and detection of specific antibodies. Unfortunately, especially neuroimaging is rarely available in endemic countries. The authors analyzed the value of a test that detects antigens that are excreted by living cysts in people with epilepsy. Different diagnostic scenarios and cut-off values are discussed with the respective sensitivity and specificity of the test. When using the antigen-detecting test, considerably more people with epilepsy were diagnosed correctly with neurocysticercosis. There are some concerns about possible false positive results in other cases. The test was useful for the detection of people with living cysts (active neurocysticercosis), who need further diagnostic evaluation and specific treatment. The authors recommend the addition of this test in the diagnostic criteria for neurocysticercosis.

Extraparenchymal neurocysticercosis in the United States

Neurocysticercosis (NCC) is endemic in the developing world but is becoming more common in the United States because of immigration. Although NCC is pleomorphic in its presentation, extraparenchymal NCC may be challenging to diagnose and treat. Extraparenchymal NCC is probably more frequent than previously thought. Neurologists and neuroradiologists in the United States are often unaware of the pretreatment/post-treatment radiographic patterns of extraparenchymal NCC and the potentially poor prognosis if not correctly diagnosed and managed. The review of this condition is important given increasing incidence in the United States.

Neglected infections of poverty in Texas and the rest of the United States: management and treatment options

In the poorest regions of the United States, especially along the Gulf Coast and in South Texas, are a group of endemic parasitic and related infections known as the neglected infections of poverty. Such infections are characterized by their chronicity, disabling features, and disproportionate impact on the estimated 46 million people who live below the U.S. poverty line. Today more Americans live in poverty than ever before in the half-century that the Census Bureau has been recording poverty rates. In association with that poverty, a group of major neglected infections of poverty have emerged in the United States. Here we describe the major neglected infections of poverty in the United States, with a brief overview of their significant epidemiological features, their links with poverty, and our approaches to their diagnosis, management, and treatment.

A review on diagnostic and preventive aspects of cystic echinococcosis and human cysticercosis

Cystic echinococcosis and human cysticercosis have recently been included in the list of "neglected tropical diseases" by the World Health Organization (WHO). Both are zoonoses which are prevalent throughout the world and lead to considerable mortality, morbidity, and economic losses as well. This review deals with the disease burden of these two neglected cestode infections. Diagnostic modalities with their specific advantages and disadvantages have also been discussed. Recent developments in immunodiagnostic assays for the two diseases have been dealt with. Various control strategies including the use of veterinary vaccines have been highlighted.

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.

Human neurocysticercosis: in vivo expansion of peripheral regulatory T cells and their recruitment in the central nervous system

Human neurocysticercosis (NC) is caused by Taenia solium larvae lodged in the central nervous system. Most cases occur with no, or mild, neurological symptoms. However, in some patients, neuroinflammation is exacerbated, leading to severe forms of the disease. Considering the critical role of regulatory T cells (Tregs) in balancing inflammation in chronic diseases, their participation in restraining the inflammatory response in NC was explored in the present study. The frequency of Tregs and their relationship with the level of the proliferative response, the level of activated lymphocytes, and the cytokines expressed were determined in severe NC patients compared with those from healthy donors. Significantly increased peripheral Tregs (CD4(+)CD25(high) and CD4(+)CD25(high)FoxP3(+), CD4(+)CD25(high)CTLA4(+), and CD4(+)CD25(high) IL10(+)) and a significant decrease in activated (CD38(+) and CD69(+)) T cells were observed in 19 NC patients versus 10 healthy subjects. Significantly increased Tregs in NC are accompanied by a depressed specific, and non-specific, lymphocyte proliferative response, and they negatively correlate with activated CD4(+)CD69(+) lymphocytes. Treg frequencies were also determined in cerebral spinal fluid for 8 of the 19 NC patients. A positive significant correlation between peripheral and local Tregs was observed. Here, we report for the first time data that support the possible contribution of local and systemic Tregs in limiting neuroinflammation in NC.

Specific phage-displayed peptides discriminate different forms of neurocysticercosis by antibody detection in the serum samples

Neurocysticercosis (NC), caused by Taenia solium metacestode, infects the central nervous system and is a devastating parasitic infection. Diagnosis is based on symptoms, imaging, serology and epidemiology. Current markers present variable sensitivity and specificity, frequent cross-reactions and are not able to discriminate NC clinical forms. The aim of this study was to select mimotopes of T. solium metacestode antigens that may be used in NC immunodiagnosis, specifically to discriminate between active and inactive forms. A random peptide phage display library was screened against IgY from chickens immunized with total saline extract from T. solium metacestodes and validated against 110 serum samples, classified into active NC (18), inactive NC (22), cross-reactive parasitic diseases (40) and healthy controls (30). We have successfully selected seven peptides with significant immunoreactivity to IgG of NC patients, with sensitivity ranging from 95.5% to 100% to detect the inactive form and specificity varied from 85.7% to 94.3%. One phage-displayed peptide (Cc48) can be directly used as biomarker to distinguish inactive from active forms with an accuracy of 95.7%, and this novel mimotope may also be used as an auxiliary tool to neuroimaging tests and treatment follow-up.