Background:Neurocysticercosis (NCC) is the most prevalent helminth infection affecting the human central nervous system. Although neuroimaging is required for definitive diagnosis, serology supports case confirmation and clarifies diagnostic doubts. Serology gold standard is antibody detection using the enzyme-linked immunoelectrotransfer blot assay, which uses 7 antigenic lentil-lectin purified parasite glycoproteins (LLGP-EITB). LLGP-EITB is poorly accessible to low-resource settings due to its technical complexity and costs, and it is inaccessible in many settings in which parasitic material to produce antigens is not readily available. We recently developed a 3-antigen multiantigen print immunoassay (MAPIA) based on recombinant/synthetic antigens (rGP50, rT24H, and sTs14), corresponding to the 3 principal diagnostics antigenic families from LLGP-EITB, that is simpler and does not require parasite-derived materials. Methods:MAPIA performance was evaluated using a well-defined set of serum samples from NCC patients confirmed by imaging, including 73 samples from subarachnoid NCC, 72 with >5 parenchymal cysts, 59 with 3-5 parenchymal cysts, 95 with 1-2 parenchymal cysts, and 77 healthy negative controls and compared it with the LLGP-EITB performance. Results:Overall, our MAPIA presented a sensitivity of 97.7% and a specificity of 97.4%. Subgroup analyses by NCC type demonstrated a sensitivity of 100% for subarachnoid and parenchymal NCC with >5 cysts and a slight decrease for the groups with 3-5 cysts (96.6%) and 1-2 cysts (94.7%). Observed agreement with the LLGP-EITB assay was 98.33%. Conclusions:Our 3-antigen MAPIA obtained comparable results to LLGP-EITB and emerges as a simpler, reproducible, and easy-access alternative tool for antibody diagnosis in NCC.

Taenia solium causes an estimated 2.8 million disability-adjusted life years annually and substantial economic burdens in endemic regions. Understanding pig infection dynamics is essential for control, yet age-dependent susceptibility, acquired immunity, and spatially heterogeneous exposure are rarely represented in transmission models. We integrated experimental infection data across pig age groups into a local-scale agent-based model (ABM) of T. solium transmission. The model includes age-related susceptibility peaking at weaning, immunity elicited by egg exposure, and heterogeneous pig-environment interactions derived from GPS-tracked movements. We compared four model configurations: baseline, immunity only, exposure heterogeneity only, and combined. Calibration and validation used human taeniasis and pig cysticercosis prevalence data from eight rural Peruvian villages; intervention scenarios included mass vaccination and anthelmintic treatment. All configurations fit observed data well, but models incorporating heterogeneous susceptibility concentrated 95% of infections before 6.5 months (versus distributed across lifespan in baseline). The combined model best reproduced empirical cyst burden distributions, with 2.2% of pigs harboring 87% of total cysts, approaching the observed 99.2% aggregation. Immunity attenuated post-intervention prevalence rebounds. Mass pig vaccination reduced pig cysticercosis prevalence by 16% in models without immunity but had negligible effect when immunity was included, indicating age-targeted interventions are essential; lower age cut-off needs maternal immunity data for cost-effective control. Integrating pig immunity and exposure heterogeneity improves T. solium transmission model realism and provides a more accurate framework for intervention design and evaluation.

Residual brain calcifications that occur after antiparasitic treatment in neurocysticercosis (NCC) can serve as foci of enduring neuroinflammation and associated seizures. Etidronate, a first-generation bisphosphonate, has exhibited efficacy in reducing the formation of ectopic brain calcification. In the present proof-of-concept study, its effects on post-treatment calcifications were evaluated in 12 pigs naturally infected with NCC, confirmed via magnetic resonance imaging. All animals received albendazole plus praziquantel for 5 days, either alone (n = 6) or with etidronate (20 mg/kg/day for 2 weeks, then 10 mg/kg/day for 8 weeks; n = 6). Eight months post-treatment, the animals were euthanized for ex vivo brain computed tomography, histology, and scanning electron microscopy of calcified lesions. Etidronate reduced the risk of calcification by 21% (risk ratio = 0.79; 95% CI: 0.65-0.90; P = 0.020); however, there was considerable individual variability in the magnitude of this risk reduction, as well as significantly decreased calcium and phosphorus content in granulomas. Etidronate was well tolerated and may serve as an adjunctive therapy to reduce residual calcification after antiparasitic treatment in NCC.

The objective of the study was to assess the frequency of interictal epileptiform discharges (IEDs) in calcified neurocysticercosis (NCC) and its relationship with calcification burden. Forty-nine patients with calcified NCC (low-burden, 1-2 calcifications, n = 24; high-burden, ≥15 calcifications, n = 25) and seizure history underwent prolonged (8-h) electroencephalography (EEG), interpreted by epileptologists who were blinded to patient history and calcification category. Clinical seizure outcomes were also assessed. We found that IEDs occurred in 7 of 49 participants (14.3%), with no difference between low-burden (12.5%) and high-burden (16.0%) groups (p = 1.000). All IEDs (spikes and/or sharp waves) in the high-burden group (n = 4) were high-voltage (100-150 μV), whereas those in the low-burden group (n = 3) were low or medium voltage (20-70 μV). Among the participants who had IEDs, 5 (71.4%) had seizures in the last year, compared with 14 (33.3%) in the group without IEDs detected (p = 0.093). Among 19 participants with seizures in the last year, 5 were identified as having drug-resistant epilepsy (DRE). All five cases of DRE occurred in individuals with 15 or more calcifications (5/25, 20%, vs 0/24, p = 0.023). We conclude that IEDs occur frequently in individuals with calcified NCC. Although calcification burden itself was not associated with the presence of IEDs, drug-resistant cases and high-voltage IEDs were concentrated in the high-burden group, supporting the role of calcified parasites as epileptogenic foci.

BackgroundNeurocysticercosis (NCC), a parasitic brain infection caused by Taenia solium larvae, remains a leading cause of preventable epilepsy globally. Although calcified brain lesions were formerly considered as the quiescent end stage of NCC, they may act as epileptogenic foci. It has been suggested that parasitic antigens within calcified lesions may act as potential triggers of inflammation and subsequent seizure activity. In this study, we developed and optimized immunohistochemistry (IHC) assays employing anti-Taenia solium monoclonal antibodies (mAbs) to detect residual cyst antigens in calcified lesions in a porcine NCC model and assessed antigen persistence for up to 12 months after successful antiparasitic treatment.Methods/principal findingsSix mAbs raised against T. solium whole cyst (TsW5, TsW8, and TsW12), vesicular fluid (TsV3 and TsV4), and excretory/secretory products (TsE1) were used for IHC assay development and tested in brain sections containing viable brain cysts from NCC pigs and uninfected tissue from controls to optimize assay conditions, blocking, primary and secondary antibody dilutions. Optimized assays were subsequently performed in selected calcified granulomas (n = 20) obtained from NCC-infected pigs sacrificed at 4, 8, and 12 months after antiparasitic treatment to identify residual cyst antigens as well as their localization and area of reactivity. We observed residual cyst antigens in 65-80% of calcified granulomas, with TsW8 and TsV3 showing the highest percentages of immunoreactivity. Antigen localization followed two patterns, one with antigens entirely located within the calcified lesions (TsW5, TsW8, TsW12, and Tsv4) and another with antigens located outside the cyst in the perilesional brain tissue (TsV3 and TsE1). Antigen detection and the extent of reactivity declined progressively after antiparasitic treatment but persisted at detectable immunoreactive areas in calcified granulomas up to month 12 months after treatment.Conclusions/significanceT. solium antigens remain detectable in calcified granulomas and in the perilesional tissue for up to 12 months after antiparasitic treatment in the pig model.

Objective:People with epilepsy of childbearing potential in low-resource settings face unique challenges related to anti-seizure medication (ASM) selection and access. These challenges may be particularly pronounced in regions where neurocysticercosis (NCC), a leading cause of acquired epilepsy worldwide, contributes substantially to the burden of disease. We characterized ASM prescribing patterns and factors associated with the use of higher-risk medications among people with epilepsy of childbearing potential in northern Peru. Methods:We analyzed data from females aged 15-49 years who were enrolled in a prospective, population-based epilepsy cohort in Tumbes, Peru, from 2006 to 2020. ASMs were categorized according to pregnancy-associated safety profiles as Lower-risk (lamotrigine, levetiracetam, oxcarbazepine, clonazepam, diazepam), Intermediate-High risk (carbamazepine, phenytoin, phenobarbital, topiramate), and Highest-risk (valproic acid). We evaluated ASM utilization, polytherapy, and factors associated with valproate use, the highest-risk medication. Results:Among 1,975 individuals with epilepsy, 685 were of childbearing potential. Approximately one-third met criteria for probable or definite NCC (34.9%). Nearly all participants (98.6%) were prescribed carbamazepine, phenytoin, phenobarbital, or valproic acid, while use of newer-generation agents was rare. Most prescriptions (86.3%) were classified as Intermediate-High-risk, and 12.8% as Highest-risk. In multivariable analyses, prior ASM use and polytherapy were independently associated with receipt of valproate. Discussion:In this population-based epilepsy cohort from northern Peru, ASM treatment among people of childbearing potential was overwhelmingly limited to older medications with an elevated risk of teratogenicity. These prescribing patterns likely reflect medication availability rather than clinical preference and highlight the challenges of implementing guideline-recommended epilepsy care in resource-constrained settings. Given the substantial burden of NCC-related epilepsy in this population, improving access to safer and more diverse ASM options may represent an important strategy for reducing treatment inequities among people with epilepsy of childbearing potential.

INTRODUCTION:Neurocysticercosis is a leading cause of acquired epilepsy in endemic regions. Scarce longitudinal data sets exist to allow assessment of secular trends in prevalence. This study analysed temporal trends of cysticercosis seropositivity among suspected patients across Peru over two decades. MATERIALS AND METHODS:An ecological study was conducted using anonymized serological data from patients who underwent enzyme-linked immunoelectrotransfer blot (EITB) testing for the first time at a neurological referral centre in Lima, Peru. Seropositivity was defined as antibody reactivity to ≥ 1 glycoprotein band, and higher thresholds (≥ 3, ≥ 4 bands) were also assessed considering their association with active disease. Temporal trends were analysed using generalised linear models with Poisson regression. RESULTS:Among 39,481 individuals, seropositivity was 31.3% (12,350/39,481). The prevalence of seropositivity increased from 27.3% in the initial 5-year period (2000-2004) to 37.4% in the last (2014-2019), while the numbers of requested tests decreased from 15,074 to 5130 and the overall numbers of new seropositive individuals decreased from 4109 cases to 1918. High-reactivity cases also increased in proportion but decreased in number (≥ 3 bands: 18.1% to 27.1% and 2734 to 1392; ≥ 4 bands: 7.9% to 17.5% and 1194 to 897), suggesting a greater proportion of active or clinically relevant infections. CONCLUSIONS:Over 20 years, the demand for cysticercosis serology and the numbers of seropositive cases by 5-year periods decreased while the proportion of seropositive cases rose significantly within a single specialised referral centre. While data from suspected clinical cases do not necessarily represent disease burden at the population level, the reduction in case numbers may represent reduced disease prevalence. At the same time, the persistence of significant numbers of cases in this single centre study through the last examined period and the increased proportion of strong seropositive cases demonstrate that cysticercosis is still endemic in Peru.

PURPOSE OF REVIEW:Parasitic infections of the human nervous system are frequently overlooked as causes of neurological morbidity, mostly because of lack of diagnostic awareness from clinicians in developed countries. Although limited and unfunded, research in neuroparasitoses leads to improved diagnostic and treatment approaches, and improvements in immunological, molecular and imaging techniques provide new insights in these neglected infections. This review succinctly describes most parasitic infections affecting humans and highlights new information available in the literature. RECENT FINDINGS:Despite the fact that primary research reports in parasitic neuroinfection are sparse, a body of information on new diagnostic techniques, clinical manifestations, and more recent therapeutic approaches is now available, with particular emphasis in molecular techniques including deep sequencing, and minimally invasive surgical techniques. SUMMARY:This review provides a quick overview of most parasitic infections affecting the human nervous system, and summarizes updated information on current diagnostic and treatment approaches, providing a comprehensive reference, of particular use for clinicians working in settings where neuroparasitoses are infrequent.

Background:Calcareous corpuscles are mineralized structures characteristic of cestodes, including Taenia solium, yet their protein composition and antigenic properties remain poorly characterized. Existing studies have focused mainly on calcium-binding fractions, limiting understanding of the broader molecular content of these structures. Methods:A two-phase methodology was developed to isolate calcareous corpuscles from viable T. solium cysticerci obtained from naturally infected pigs and to recover their associated proteins. Corpuscles were isolated by mechanical homogenization and differential centrifugation, followed by controlled chemical dissolution. Protein recovery was assessed by Bradford assay and SDS-PAGE. Antigenic properties were evaluated using immunofluorescence and Western blot with a panel of monoclonal antibodies raised against whole cysticercus extract, vesicular fluid, and excretion-secretion antigens. Results:The optimized protocol consistently yielded intact calcareous corpuscles and enabled complete dissolution of the mineral matrix with sequential release of proteins. Electrophoretic analysis revealed a heterogeneous protein profile comprising at least 23 distinct protein bands. Several proteins were recurrently detected by multiple monoclonal antibodies, particularly bands around 66.9 kDa and in the low-molecular-weight range. Western blot analysis confirmed specific recognition of corpuscle-associated proteins by a subset of monoclonal antibodies. Conclusions:Calcareous corpuscle-enriched preparations yielded a diverse set of immunoreactive proteins. The methodology described here provides a reproducible framework for further proteomic characterization and may facilitate future proteomic, diagnostic, and immunological studies in cysticercosis and neurocysticercosis.

AIMS:Subarachnoid neurocysticercosis is an aggressive form of Taeniasoliuminfection characterized by uncontrolled expansion of subarachnoid cysts. This study aims to investigate the role of exogenous lipidsand TGF-βin the proliferation of germinative cells and bladder wall expansion, providing insights into the biological mechanisms underlying cyst growth. MATERIAL & METHODS:Germinative cells and bladder wall sections discarded after surgical resection of subarachnoid cysts in humans were cultured in vitro under axenic conditions. The effects of TGF-βand exogenous lipids, both individually and combined, were assessed through proliferation assays and morphological analysis to determine their role in cyst expansion. RESULTS:TGF-β-mediatedsignaling was found to be crucial for germinative cell replication, with lipid supply further enhancing bladder wall expansion. Long-term viability of cultured bladder wall sections was successfully maintained, enabling extended analysis of cyst biology. CONCLUSIONS:Thisinvitrosystem provides a powerful platform for characterizing the biology of subarachnoid cysts and for testing new therapeutic agents aimed at improving the treatment of human neurocysticercosis.

Neurocysticercosis (NCC) is the most common helminthic infection of the human central nervous system (CNS), and a major cause of acquired epilepsy in most of the world. Although outcomes of NCC have been improved by advanced diagnostic tests, antiparasitic drugs, and appropriate anti-inflammatory treatment, little attention has been paid to calcified NCC. Calcification is a common outcome in NCC and carries increased risk for seizures and hippocampal atrophy/sclerosis. The pathophysiological mechanisms leading to calcification instead of complete resolution are basically unknown. Understanding the causes and mechanisms of calcification can lead to improved therapies aimed at reducing the likelihood of residual calcification or the underlying pathological mechanisms, after the resolution of parasitic lesions in the human CNS.

Identifying viable infections in neurocysticercosis (NCC) is crucial for treatment. Neuroimaging is the primary diagnostic tool, but it is not widely available. Moreover, in many cases, imaging diagnosis is not pathognomonic and requires serological confirmation. The serological assay of choice, enzyme-linked immunoelectrotransfer blot using lentil lectin-purified glycoprotein (LLGP-EITB) Taenia solium antigens to detect specific antibodies, exhibits high predictive values for the presence of viable NCC when the results are positive for multiple (>3) antibody bands; it also exhibits high predictive values for the absence of viable infection when the results are negative or the test reacts to a single antibody band. However, its interpretation in terms of viable infection is limited in cases with two or three positive bands (intermediate results), which occur in one-quarter of patients with NCC. The quantification of specific antibodies could allow for the identification of viable infections. Using a multi-antigen, quantitative multiplex bead assay, antibody levels were measured against Taenia solium proteins rGP50, rT24H, and sTs18var1 in 94 patients with intermediate LLGP-EITB results. The antibody-to-rT24H (25.96 versus 5.49; P = 0.0048) and antibody-to-sTs18var1 ratios (3.62 versus 1.37; P = 0.0083) were higher in subjects with viable cysticerci than in controls. Patients with high antibody levels against the proteins rT24H and sTs18var1 were 5.4 times more likely to have a viable infection than those with low antibody levels. The quantification of antibodies against rT24H and sTs18var1 can help define a viable NCC infection.

The taeniasis/cysticercosis complex, caused by Taenia solium, is a significant zoonotic disease in low- and middle-income countries. Although this complex has been extensively studied in rural communities, information on its status in urban areas remains limited due to the financial and logistical challenges of conducting large-scale assessments in cities. This study aimed to demonstrate the feasibility of using wastewater monitoring for the epidemiological surveillance of T. solium in cities. We evaluated four extraction methods (magnetic beads, bead-beating, spin column, and thermal shock) on serial dilutions of T. solium eggs. Statistical analysis demonstrated that the magnetic bead method achieved the highest quantifications of genomic copies (GC). These values were used to develop a simple linear regression to establish an equivalence between the GC of the internal transcribed spacer 1 (ITS-1) region and eggs. Subsequently, we assessed the performance of skimmed milk flocculation, along with the impact of inhibitory substances, in two distilled water samples and two wastewater samples (250 mL each) seeded with low (5000) and high (25000) eggs numbers. Recovery percentages in distilled water were 98 ± 6 % (high concentration) and 26 ± 11 % (low concentration), while in wastewater, they were 76 ± 11 % and 12 ± 3 %, respectively. Over 16 months, wastewater monitoring in a highly endemic city of the Peruvian Central Highlands detected T. solium in 17 % (12/70) of samples using a real-time polymerase chain reaction targeting the T. solium ITS-1 region, with concentrations ranging from 8.92E+02 to 8.07E+06 GC/100 mL, equivalent to 0.7 and 4510 eggs/100 mL, respectively. Sanger sequencing of the cytochrome c oxidase subunit 1 gene confirmed the presence of T. solium in 4 of the 12 positive samples for the ITS-1 region. In conclusion, T. solium can be detected and quantified in wastewater, supporting its use for urban human taeniasis surveillance.

BACKGROUND:Calcified neurocysticercosis (NCC), the end stage of brain cysts of the pork tapeworm Taenia solium is a common cause of epilepsy. Calcified NCC lesions are not inert and represent potential epileptogenic foci. Understanding the mechanisms of residual calcification in NCC is hindered by the difficulty of accessing human brain biopsies. Since cyst degeneration can be induced by antiparasitic treatment (APT) in NCC-infected pigs, this study assessed the residual calcification process in this model at three time points after APT. METHODS/PRINCIPAL FINDINGS:Fifteen naturally infected pigs with viable NCC confirmed by magnetic resonance imaging received APT with albendazole and praziquantel and were sacrificed after 4, 8, and 12 months (n = 5 each). The pigs' brains were removed and processed by ex vivo CT scan to assess the proportion of cysts that calcified by post-treatment time points using risk ratios (RR) from Poisson regression. Radiodensity levels (Hounsefield units) of calcified lesions were also measured and compared using linear coefficients from log-transformed values in generalized linear models. The overall proportion of residual calcification on CT scan was 63.9% (156 calcified lesions/244 viable cysts), being statistically higher in treated NCC pigs at 4 months (83.3% [50/60], RR = 2.61, P < 0.001) and 8 months (82.8% [77/93], RR = 2.59, P < 0.001) versus 12 months (31.9% [29/91]). At 8 months after APT, calcifications were more dense (100.6 ± 3.6 HU) compared to 12 months (74.4 ± 3.6 HU, β = 0.37, P = 0.010) and marginally higher compared to 4 months (85.2 ± 3.8 HU, β = 0.24, P = 0.096), and were also larger and more frequently found on histopathology. CONCLUSION/SIGNIFICANCE:Calcification in NCC is a dynamic process that can be induced and monitored in naturally infected pigs. Eight months after treatment seems to be an optimal time point for assessing residual calcification.

Neurocysticercosis is the leading cause for acquired epilepsy worldwide, and it is caused by the larval stage of the parasite Taenia solium. Several proteins of this stage have been characterized and studied to understand the parasite-host interaction, however, the proteins from the early cysticercus stages (the postoncospheral form) have not yet been characterized. The study of the postoncospheral form proteins is important to understand the host-parasite relationship in the early stages of infection. The aim of this work was to identify postoncospheral form antigenic proteins using sera from neurocysticercosis patients. T. solium activated oncospheres were cultured in HCT-8 cells to obtain the postoncospheral form. Soluble total and excretory/secretory proteins were obtained from the postoncospheral form and were incubated with both pool sera and individual serum of neurocysticercosis positive human patients. Immunoblotting showed target antigenic proteins with apparent molecular weights of 23kDa and 46-48kDa. The 46-48kDa antigen bands present in soluble total and excretory/secretory postoncospheral form proteins were analyzed by LC-MS/MS; proteins identified were: nuclear elongation factor 1 alpha, enolase, unnamed protein product/antigen diagnostic GP50, calcium binding protein calreticulin precursor and annexin. The postoncospheral form expresses proteins related to interaction with the host, some of these proteins are predicted to be exosomal proteins. In conclusion, postoncospheral proteins are consistent targets of the humoral immune response in human and may serve as targets for diagnosis and vaccines.

Despite being a leading cause of acquired seizures in endemic regions, the pathological mechanisms of neurocysticercosis are still poorly understood. This study aims to investigate the impact of anthelmintic treatment on neuropathological features in a rat model of neurocysticercosis. Rats were intracranially infected with Taenia solium oncospheres and treated with albendazole + praziquantel (ABZ), oxfendazole + praziquantel (OXF), or untreated placebo (UT) for 7 days. Following the last dose of treatment, brain tissues were evaluated at 24 h and 2 months. We performed neuropathological assessment for cyst damage, perilesional brain inflammation, presence of axonal spheroids, and spongy changes. Both treatments showed comparable efficacy in cyst damage and inflammation. The presence of spongy change correlated with spheroids counts and were not affected by anthelmintic treatment. Compared to white matter, gray matter showed greater spongy change (91.7% vs. 21.4%, p < 0.0001), higher spheroids count (45.2 vs. 0.2, p = 0.0001), and increased inflammation (72.0% vs. 21.4%, p = 0.003). In this rat model, anthelmintic treatment destroyed brain parasitic cysts at the cost of local inflammation similar to what is described in human neurocysticercosis. Axonal spheroids and spongy changes as markers of damage were topographically correlated, and not affected by anthelmintic treatment.

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.