Epilepsy and neurocysticercosis: an incidence study in a Peruvian rural population

Concordance between a New Rapid Point-Of-Care Assay and Standard ELISA in the Detection of Cysticercosis Antigens in Urine

Neurocysticercosis is a parasitic disease of major public health importance. Definitive diagnosis requires neuroimaging, which is typically unavailable in rural impoverished regions of endemicity. Screening immunoassays can support diagnosis in this setting by identifying individuals most likely to have severe forms of disease for referral to imaging. Urine sampling is convenient, painless, and generally well accepted. We developed a rapid point-of-care (POC) assay to detect urinary antigens and assessed concordance with a standard antigen ELISA (Ag-ELISA), both using monoclonal antibodies TsW8/TsW5. From 28,145 stored community samples with Ag-ELISA results, we selected 843 for comparison, 281 each from nonreactive (ratio <1), reactive-below-cutoff (ratio 1:3), and positive (ratio ≥3) samples. Overall agreement was 73.6%, with strong agreement observed in the nonreactive (280/281, 99.6%) and positive (255/281, 90.8%) groups. This affordable noninvasive POC test can be applied to identify individuals in the community most at risk of developing severe disease.

Neurocysticercosis: Isolated Lesion in the Left Middle Frontal Gyrus

OBJECTIVE

Neurocysticercosis (NCC) is one of the most common parasitic infections of the central nervous system. We present a case study of a 21-year-old African man with an isolated NCC lesion to the left middle frontal gyrus, which is also known as the dorsolateral prefrontal cortex (dlPFC).

METHOD

A neuropsychological evaluation was requested by the patient's inpatient psychiatry team regarding worsening attention and depressive symptoms approximately 6 months after NCC diagnosis and treatment.

RESULTS

Neuropsychological findings revealed deficits in the aspects of executive functioning, attention, working memory, and significant depressive symptoms.

CONCLUSION

To our knowledge, this is the first case study of its kind demonstrating deficits in cognitive functioning consistent with the dlPFC lesion location. Sociocultural and linguistic considerations, clinical findings, and limitations are discussed.

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.

CystiHuman: A model of human neurocysticercosis

INTRODUCTION

The Taenia solium tapeworm is responsible for cysticercosis, a neglected tropical disease presenting as larvae in the body of a host following taenia egg ingestion. Neurocysticercosis (NCC), the name of the disease when it affects the human central nervous system, is a major cause of epilepsy in developing countries, and can also cause intracranial hypertension, hydrocephalus and death. Simulation models can help identify the most cost-effective interventions before their implementation. Modelling NCC should enable the comparison of a broad range of interventions, from treatment of human taeniasis (presence of an adult taenia worm in the human intestine) to NCC mitigation. It also allows a focus on the actual impact of the disease, rather than using proxies as is the case for other models.

METHODS

This agent-based model is the first model that simulates human NCC and associated pathologies. It uses the output of another model, CystiAgent, which simulates the evolution of pig cysticercosis and human taeniasis, adding human and cyst agents, including a model of cyst location and stage, human symptoms, and treatment. CystiHuman also accounts for delays in the appearance of NCC-related symptoms. It comprises three modules detailing cyst development, seizure probability and timing, and intracranial hypertension/hydrocephalus, respectively. It has been implemented in Java MASON and calibrated in three endemic villages in Peru, then applied to another village (Rica Playa) to compare simulation results with field data in that village.

RESULTS AND DISCUSSION

Despite limitations in available field data, parameter values found through calibration are plausible and simulated outcomes in Rica Playa are close to actual values for NCC prevalence and the way it increases with age and cases with single lesions. Initial simulations further suggest that short-term interventions followed by a rapid increase in taeniasis prevalence back to original levels may have limited impacts on NCC prevalence.

Incidence of Adult-Onset Epilepsy and the Contributory Role of Neurocysticercosis in a Five-Year, Population-Based, Prospective Study in Rural Ecuador

This prospective cohort study aimed to assess incidence and etiology of adult-onset epilepsy in previously seizure-free Atahualpa residents aged ≥ 20 years. Persons with adult-onset epilepsy occurring over 5 years were identified from annual door-to-door surveys and other overlapping sources. Those who emigrated or declined consent were excluded at the administrative censoring date of the last survey when these subjects were interviewed. Persons who died and those who developed incident epilepsy were censored at the time of these outcomes. Poisson regression models adjusted for demographics, education, alcohol intake, and the length of observation time, were used to estimate annual adult-onset epilepsy incidence rate ratio and cumulative incidence. Systematic neuroimaging screening was offered to participants to get insights on the etiology of epilepsy. Individuals enrolled in this cohort (N = 1,480) contributed to 6,811.6 years of follow-up. Seventeen developed incident adult-onset epilepsy, for an annual incident rate of 249.2 per 100,000 persons-year (95% CI: 130.7-367.7). Cumulative incidence was 1,245.9 per 100,000 persons (95% CI: 653.7-1,838.3) after a mean of 4.6 (SE: 0.06) years of follow-up. Six persons with incident epilepsy had neurocysticercosis (35%). Individuals with neurocysticercosis were six times more likely to develop adult-onset epilepsy than those without this disease (IRR: 6.01; 95% CI: 2.16-16.7), after adjusting for relevant covariates. The attributable fraction of incident adult-onset epilepsy due to neurocysticercosis was 30.9% (95% CI: 25.6-46.2%). This rural Ecuadorian population has a high incidence of adult-onset epilepsy, with neurocysticercosis being an important contributory cause.

Incidence and prevalence of epilepsy and associated factors in a health district in North-West Cameroon: A population survey

This population-based cross-sectional survey with a follow-up case-control study assessed the prevalence, incidence, and risk factors for epilepsy in a rural health district in the North-West Region of Cameroon. Community-based epilepsy screening targeted all inhabitants, six years and older, in all 16 health areas in the Batibo Health District. During door-to-door visits, trained fieldworkers used a validated questionnaire to interview consenting household heads to screen for epilepsy in eligible residents. Trained physicians subsequently assessed people with suspected seizures. After clinical assessment, they confirmed or refuted the diagnosis and estimated the date of epilepsy onset. A trained nurse interviewed people with epilepsy and randomly selected healthy individuals, obtaining relevant demographic details and information on exposure to risk factors for epilepsy. Out of 36,282 residents screened, 524 had active epilepsy. The age-standardized prevalence of active epilepsy was 33.9/1,000 (95% CI: 31.0-37.1/1,000). We estimated the one-year age-standardized epilepsy incidence at 171/100,000 (95%CI: 114.0-254.6). Active epilepsy prevalence varied widely between health areas, ranging between 12 and 75 per 1,000. The peak age-specific prevalence was in the 25-34 age group. In adults, multivariate analysis showed that having a relative with epilepsy was positively associated with epilepsy. Epilepsy characteristics in this population, geographical heterogeneity, and the age-specific prevalence pattern suggest that endemic neurocysticercosis and onchocerciasis may be implicated. Further investigations are warranted to establish the full range of risk factors for epilepsy in this population.

Incidence and prevalence of epilepsy in the Republic of North Macedonia: Data from nationwide integrated health care platform

PURPOSE

This study aimed to evaluate the incidence and period prevalence of epilepsy in the Republic of North Macedonia, an upper-middle-income country with universal access to healthcare, based on a nationwide healthcare platform (NHP).

METHODS

NHP contains reports from all inpatient and outpatient medical encounters and procedures, and all electronic medical records are linked together with a unique patient number. We performed the analysis of the data maintained at the Macedonian Ministry of Health, concerning the five years of the study (2014 through 2018). Population and demographic data for each year were obtained from the State Statistical Office.

RESULTS

The period prevalence was 6.67 per 1,000 inhabitants. There were 6383 (46.2%) females and 7435 (53.8%) males; the gender difference was significant: 6.17 per 1,000 females and 7.16 per 1,000 males (p = 0.0000). Between 2015 and 2018 the median annual incidence of epilepsy was 68 new epilepsy patients per 100,000, with an upward trend over time. The age-specific incidence was high in childhood and adolescence, was constant (and low) in the adult years, and gradually increased in each successive age group after the age of 50 years. The greatest incidence was found in group 70-79 years of age. The incidence in childhood and adolescence tends to gradually decrease from 2015 to 2018, while it progressively increased in population over 50 years of age, which may explain a rise in overall incidence. We found a statistically significant higher incidence in males than in females, a ratio consistently being 1.2: 1.

CONCLUSION

The data from the study provides accurate findings on the prevalence and incidence of epilepsy in the upper-middle-income Southeastern European country.

Prevalence and incidence of epilepsy in Latin America and the Caribbean: A systematic review and meta-analysis of population-based studies

OBJECTIVE

This study was undertaken to perform an updated systematic review and meta-analysis to estimate the pooled prevalence and incidence of epilepsy in Latin America and the Caribbean (LAC), describing trends over time, and exploring potential clinical and epidemiological factors explaining the heterogeneity in the region.

METHODS

Observational studies assessing the incidence or prevalence of epilepsy in LAC countries up to March 2020 were systematically reviewed according to PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. Meta-analyses and cumulative analyses were performed using random-effects models. We assessed between-study heterogeneity with sensitivity, subgroup, and meta-regression analyses. Moreover, the quality of the included studies and the certainty of evidence were evaluated using the GRADE (grading of recommendation, assessment, development, and evaluation) approach.

RESULTS

Overall, 40 studies (from 42 records) were included, 37 for prevalence analyses and six for incidence (312 387 inhabitants; 410 178 person-years). The lifetime prevalence was 14.09 per 1000 inhabitants (95% confidence interval [CI] = 11.72-16.67), for active epilepsy prevalence was 9.06 per 1000 individuals (95% CI = 6.94-11.44), and the incidence rate was 1.11 per 1000 person-years (95% CI = .65-1.70). These high estimates have been constant in the region since 1990. However, substantial statistical heterogeneity between studies and publication bias were found. The overall certainty of evidence was low. Methodological aspects (sample size) and countries' epidemiological characteristics such as access to sanitation services and child and adult mortality rates explained the high heterogeneity. Finally, the prevalence of epilepsy associated with neurocysticercosis (NCC) in the general population was high, and the proportion of NCC diagnosis among people living with epilepsy was 17.37%.

SIGNIFICANCE

The epilepsy prevalence and incidence in LAC are higher than worldwide estimates, being constant since 1990 and strongly influenced by NCC. We identified high between-study heterogeneity and significant methodological limitations (e.g., heterogeneous definitions, lack of longitudinal studies). The region needs upgraded research using standardized definitions and diagnostic methods, and urgent action against preventable causes.

Neurocysticercosis in Northern Peru: Qualitative Insights from men and women about living with seizures

BACKGROUND

Neurocysticercosis (NCC) is a helminthic disease of the central nervous system, and it is one of the leading causes of seizures and symptomatic epilepsy in countries with tropical regions like Peru. Studies of people with epilepsy in Peru's northern coast have consistently found that between 30% and 50% of epilepsy cases is associated with NCC. There are few studies that report on the differences in incidence and prevalence of NCC by sex, and to our knowledge, none that consider the gendered dimensions of having epilepsy.

METHODOLOGY

This qualitative study based on individual interviews (n = 9) and focus group discussions (n = 12) explored the challenges of diagnosis and the implications for everyday activities among men and women with epilepsy as well as the views of their family members on the impact of such condition.

PRINCIPAL FINDINGS

The explanatory models used by women to discuss their condition reflect low levels of decision-making power in areas such a reproductive health, health care access and treatment. For some women domestic violence is also a probable cause for seizures among women. The implications of living with neurocysticercosis and the accompanying seizures were reported differently by men and women. While women were mostly concerned about their capacity to perform their domestic responsibilities and their roles as mothers and caregivers; men were mostly concerned about the impact on their income generation activities. Women and men shared concern about the consequences of their condition on the wellbeing of their families.

CONCLUSIONS/SIGNIFICANCE

NCC is a disrupting experience for men and women in ways that reflect their position and roles in society: Women as caregivers within the home, men as income generators outside the home. Further gender research is needed to better understand and address the differential impacts of NCC and health system responses as well as gendered dimensions of prevalence and incidence. (268 words).

Comorbidities of epilepsy in low and middle-income countries: systematic review and meta-analysis

Epilepsy is a major public health concern in low and middle-income countries (LMICs) and comorbidities aggravate the burden associated with the disease. The epidemiology of these comorbidities has not been well described, although, identifying the main comorbidities of epilepsy, and their relative importance, is crucial for improving the quality of care. Comorbidities were defined as disorders coexisting with or preceding epilepsy, or else compounded or directly attributed to epilepsy or to its treatment. A meta-analysis of the proportion of main comorbidities by subcontinent as well as overall was also conducted. Out of the 2,300 papers identified, 109 from 39 countries were included in this systematic review. Four groups of comorbidities were identified: parasitic and infectious diseases (44% of comorbid conditions), somatic comorbidities (37%), psychosocial (11%), as well as psychiatric comorbidities (8%). Heterogeneity was statistically significant for most variables then random effect models were used. The most frequently studied comorbidities were: neurocysticercosis (comorbid proportion: 23%, 95% CI: 18-29), head trauma (comorbid proportion: 9%, 95% CI: 5-15) malnutrition (comorbid proportion: 16%, 95% CI: 28-40), stroke (comorbid proportion: 1.3%, 95% CI: 0.2-7.0), and discrimination for education (comorbid proportion: 34%, 95% CI: 28-40). Many comorbidities of epilepsy were identified in LMICs, most of them being infectious.

Unique Characteristics of Epilepsy Development in Neurocysticercosis

The parasitic helminth infection neurocysticercosis (NCC) is the most common cause of adult-acquired epilepsy in the world. Despite the serious consequences of epilepsy due to this infection, an in-depth review of the distinct characteristics of epilepsy due to neurocysticercosis has never been conducted. In this review, we evaluate the relationship between NCC and epilepsy and the unique characteristics of epilepsy caused by NCC. We also discuss recent advances in our understanding of NCC-related epilepsy, including the importance of anti-inflammatory therapies, the association between NCC and temporal lobe epilepsy, and the recent discovery of biomarkers of severe epilepsy development in individuals with NCC and seizures.

An estimation of global volume of surgically treatable epilepsy based on a systematic review and meta-analysis of epilepsy

OBJECTIVE

Epilepsy is one of the most common neurological disorders, yet its global surgical burden has yet to be characterized. The authors sought to compile the most current epidemiological data to quantify global prevalence and incidence, and estimate global surgically treatable epilepsy. Understanding regional and global epilepsy trends and potential surgical volume is crucial for future policy efforts and resource allocation.

METHODS

The authors performed a systematic literature review and meta-analysis to determine the global incidence, lifetime prevalence, and active prevalence of epilepsy; to estimate surgically treatable epilepsy volume; and to evaluate regional trends by WHO regions and World Bank income levels. Data were extracted from all population-based studies with prespecified methodological quality across all countries and demographics, performed between 1990 and 2016 and indexed on PubMed, EMBASE, and Cochrane. The current and annual new case volumes for surgically treatable epilepsy were derived from global epilepsy prevalence and incidence.

RESULTS

This systematic review yielded 167 articles, across all WHO regions and income levels. Meta-analysis showed a raw global prevalence of lifetime epilepsy of 1099 per 100,000 people, whereas active epilepsy prevalence is slightly lower at 690 per 100,000 people. Global incidence was found to be 62 cases per 100,000 person-years. The meta-analysis predicted 4.6 million new cases of epilepsy annually worldwide, a prevalence of 51.7 million active epilepsy cases, and 82.3 million people with any lifetime epilepsy diagnosis. Differences across WHO regions and country incomes were significant. The authors estimate that currently 10.1 million patients with epilepsy may be surgical treatment candidates, and 1.4 million new surgically treatable epilepsy cases arise annually. The highest prevalences are found in Africa and Latin America, although the highest incidences are reported in the Middle East and Latin America. These regions are primarily low- and middle-income countries; as expected, the highest disease burden falls disproportionately on regions with the fewest healthcare resources.

CONCLUSIONS

Understanding of the global epilepsy burden has evolved as more regions have been studied. This up-to-date worldwide analysis provides the first estimate of surgical epilepsy volume and an updated comprehensive overview of current epidemiological trends. The disproportionate burden of epilepsy on low- and middle-income countries will require targeted diagnostic and treatment efforts to reduce the global disparities in care and cost. Quantifying global epilepsy provides the first step toward restructuring the allocation of healthcare resources as part of global healthcare system strengthening.

Epidemiology of central nervous system infectious diseases: a meta-analysis and systematic review with implications for neurosurgeons worldwide

OBJECTIVE

Central nervous system (CNS) infections cause significant morbidity and mortality and often require neurosurgical intervention for proper diagnosis and treatment. However, neither the international burden of CNS infection, nor the current capacity of the neurosurgical workforce to treat these diseases is well characterized. The objective of this study was to elucidate the global incidence of surgically relevant CNS infection, highlighting geographic areas for targeted improvement in neurosurgical capacity.

METHODS

A systematic literature review and meta-analysis were performed to capture studies published between 1990 and 2016. PubMed, EMBASE, and Cochrane databases were searched using variations of terms relating to CNS infection and epidemiology (incidence, prevalence, burden, case fatality, etc.). To deliver a geographic breakdown of disease, results were pooled using the random-effects model and stratified by WHO region and national income status for the different CNS infection types.

RESULTS

The search yielded 10,906 studies, 154 of which were used in the final qualitative analysis. A meta-analysis was performed to compute disease incidence by using data extracted from 71 of the 154 studies. The remaining 83 studies were excluded from the quantitative analysis because they did not report incidence. A total of 508,078 cases of CNS infections across all studies were included, with a total sample size of 130,681,681 individuals. Mean patient age was 35.8 years (range: newborn to 95 years), and the male/female ratio was 1:1.74. Among the 71 studies with incidence data, 39 were based in high-income countries, 25 in middle-income countries, and 7 in low-income countries. The pooled incidence of studied CNS infections was consistently highest in low-income countries, followed by middle- and then high-income countries. Regarding WHO regions, Africa had the highest pooled incidence of bacterial meningitis (65 cases/100,000 people), neurocysticercosis (650/100,000), and tuberculous spondylodiscitis (55/100,000), whereas Southeast Asia had the highest pooled incidence of intracranial abscess (49/100,000), and Europe had the highest pooled incidence of nontuberculous vertebral spondylodiscitis (5/100,000). Overall, few articles reported data on deaths associated with infection. The limited case fatality data revealed the highest case fatality for tuberculous meningitis/spondylodiscitis (21.1%) and the lowest for neurocysticercosis (5.5%). In all five disease categories, funnel plots assessing for publication bias were asymmetrical and suggested that the results may underestimate the incidence of disease.

CONCLUSIONS

This systematic review and meta-analysis approximates the global incidence of neurosurgically relevant infectious diseases. These results underscore the disproportionate burden of CNS infections in the developing world, where there is a tremendous demand to provide training and resources for high-quality neurosurgical care.

Needs of exploring the burden of recent onset seizures due to neurocysticercosis and challenges in southeast Asia focusing on scenario in Malaysia

Seizures due to neurocysticercosis (NCC) is a neglected human-to-human transmitted disorder and an emerging problem worldwide. A substantial portion of recent onset seizures is known to be attributed to NCC in Taenia solium (T. solium) endemic areas where populations which neither raise pigs nor eat pig meat are also at risk. High prevalence of NCC causing epilepsy has been reported in the underdeveloped areas of Southeast Asia (SEA) however, only fragmentary information on its incidence is available in countries like Malaysia. In Malaysia T. solium infection was previously thought to be infrequent due to Muslim population majority and the religious prohibition of consuming pork, but it is not totally absent. There is an evident lack of knowledge and awareness of the actual burden, routes of transmission, and the impact of NCC in this region. The problem is assumed to be more prevalent particularly in cities because of the frequent inflow of possibly T. solium infected individuals or carriers among those who migrate from neighboring endemic countries to Malaysia. The issue of imported cases that are likely to be emerging in Malaysia is highlighted here. An accurate quantification of regional burdens of epilepsy due to NCC in Malaysia is warranted considering the disease emergence in its neighboring countries. It is suggested that the importance of NCC be recognized through quantification of its burden, and also to collect epidemiological data for its subsequent elimination in line of World Health Organization's mission for control of cysticercosis as a neglected tropical disease. In this review the need as well as a strategy for neuro-care center screening of epilepsy cases, and various issues with possible explanations are discussed. It is also proposed that NCC be declared as a reportable disease which is one of the eradicable public health problems in SEA.

Prevalence, Response to Cysticidal Therapy, and Risk Factors for Persistent Seizure in Indian Children with Neurocysticercosis

Background. Neurocysticercosis (NCC) is the commonest cause of childhood acquired epilepsy in developing countries. The use of cysticidal therapy in NCC, except "single lesion NCC," is still debated in view of its doubtful usefulness and potential adverse effects. Methods. Children presenting with first episode of seizure or acute focal neurological deficit without fever were screened for NCC and received appropriate therapy (followup done for 1 year to look for the response and side effects). Results. The prevalence of NCC was 4.5%. Most common presenting feature was generalized seizure and commonest imaging finding was single small enhancing lesion in the parietal lobe. Abnormal EEG and CSF abnormalities were found in almost half of the children. The response to therapy was very good with infrequent recurrence of seizure and adverse effects of therapy were encountered rarely. No risk factors for persistent seizure could be identified. Conclusion. Present study shows that the response to cysticidal therapy is very good in NCC as seizure recurrence was observed in only 5%, 4.2%, and 4.2% of cases at 3-month, 6-month, and 1-year followup. Adverse effects of therapy were observed in 20% of cases during therapy but they were mild and self-limiting.

Update on the Diagnosis and Management of Neurocysticercosis

Neurocysticercosis is an important cause of seizures worldwide and is endemic in most of Latin America, Sub-Saharan Africa, Southeast Asia, India, and China. Neurocysticercosis has profoundly different disease manifestations varying from asymptomatic presentation to life-threatening hydrocephalus. Clinical manifestations, pathogenesis, diagnostic methods, and optimal treatment vary with the location, number of lesions, and host response. Diagnosis is based on a combination of clinical presentation, neuroimaging findings, history of exposure, and serologic testing. Initial therapy should be focused on symptom management including seizure control and management of increased intracranial pressure. Emerging data are demonstrating that the optimal management approach varies with stage. Single enhancing or cystic lesions should be treated with albendazole and steroids. Patients with more than two cystic lesions should be treated with combination therapy with albendazole and praziquantel, whereas patients with hydrocephalus benefit from surgical management, especially with minimally invasive approaches.

Novel rat model for neurocysticercosis using Taenia solium

Neurocysticercosis is caused by Taenia solium infecting the central nervous system and is the leading cause of acquired epilepsy and convulsive conditions worldwide. Research into the pathophysiology of the disease and appropriate treatment is hindered by lack of cost-effective and physiologically similar animal models. We generated a novel rat neurocysticercosis model using intracranial infection with activated T. solium oncospheres. Holtzman rats were infected in two separate groups: the first group was inoculated extraparenchymally and the second intraparenchymally, with different doses of activated oncospheres. The groups were evaluated at three different ages. Histologic examination of the tissue surrounding T. solium cysticerci was performed. Results indicate that generally infected rats developed cysticerci in the brain tissue after 4 months, and the cysticerci were observed in the parenchymal, ventricle, or submeningeal brain tissue. The route of infection did not have a statistically significant effect on the proportion of rats that developed cysticerci, and there was no dependence on infection dose. However, rat age was crucial to the success of the infection. Epilepsy was observed in 9% of rats with neurocysticercosis. In histologic examination, a layer of collagen tissue, inflammatory infiltrate cells, perivascular infiltrate, angiogenesis, spongy change, and mass effect were observed in the tissue surrounding the cysts. This study presents a suitable animal model for the study of human neurocysticercosis.

Taenia solium infection in Peru: a collaboration between Peace Corps Volunteers and researchers in a community based study

Background

Neurocysticercosis is a leading cause of seizures and epilepsy in most of the world, and it occurs when Taenia solium larval cysts infect the central nervous system. T. solium tapeworm infection is endemic in much of Peru, but there are scarce data on the prevalence in many rural highland communities where it is likely to be hyper-endemic. Peace Corps Volunteers live and work in these communities; however, to our knowledge, they have not been used to facilitate public health research.

Materials and Methods

We utilized Peace Corps Volunteers to estimate the prevalence of T. solium tapeworm infection in seven rural communities in northern Peru. A convenience non-random sampling frame was used. Peace Corps Volunteers facilitated the collection of stool samples (N = 2,328), which were analyzed by sedimentation and microscopy. Niclosamide treatment and purgation preceded species identification, which was done by PCR-REA.

Results

Taenia sp. egg-positive stool samples were found in three of the seven communities we surveyed. The overall prevalence of Taenia sp. egg positivity was 2.1% (49/2,328) (95% CI = 1.6–2.8%) with prevalence up to 4.3% (42/977) (95% CI = 3.1–5.8%) by community. All 34 of the specimens tested by PCR-REA were T. solium. The overall prevalence of T. solium tapeworm infection was 1.5% (34/2,328) (95% CI = 1.0–2.0%). Prevalence up to 2.9% (28/977) (95% CI = 1.9–4.1%) by community was observed.

Conclusion/Significance

This study recorded high T. solium tapeworm prevalence, and identified hyper-endemic rural communities. It demonstrates that synergy between researchers and Peace Corps Volunteers can be an effective means to conducting large-scale, community-based studies in remote areas of Peru.

Incidence of human Taenia solium larval Infections in an Ecuadorian endemic area: implications for disease burden assessment and control

BACKGROUND

Human cysticercosis is a zoonotic disease causing severe health disorders and even death. While prevalence data become available worldwide, incidence rate and cumulative incidence figures are lacking, which limits the understanding of the Taenia solium epidemiology.

METHODOLOGY/PRINCIPAL FINDINGS

A seroepidemiological cohort study was conducted in a south-Ecuadorian community to estimate the incidence rate of infection with and the incidence rate of exposure to T. solium based on antigen and antibody detections, respectively. The incidence rate of infection was 333.6 per 100,000 person-years (95% CI: [8.4-1,858] per 100,000 person-years) contrasting with a higher incidence rate of exposure 13,370 per 100,000 person-years (95% CI: [8,730-19,591] per 100,000 person-years). The proportion of infected individuals remained low and stable during the whole study year while more than 25% of the population showed at least one antibody seroconversion/seroreversion during the same time period.

CONCLUSIONS/SIGNIFICANCE

Understanding the transmission of T. solium is essential to develop ad hoc cost-effective prevention and control programs. The estimates generated here may now be incorporated in epidemiological models to simulate the temporal transmission of the parasite and the effects of control interventions on its life cycle. These estimates are also of high importance to assess the disease burden since incidence data are needed to make regional and global projections of morbidity and mortality related to cysticercosis.

The importance of neurocysticercosis in stroke in rural areas of a developing Latin American country

There is limited information on the prevalence of neurocysticercosis (NCC) among stroke patients, and no community-based survey has addressed this issue. We performed a 3-Phase, population-based study, to assess the prevalence and pathogenesis of stroke in a rural village of coastal Ecuador, where cysticercosis is highly endemic. Twenty stroke patients were found among 642 individuals ≥ 40 years of age. Eighteen of these patients underwent neuroimaging studies and no patient had evidence of NCC or angiitis of intracranial vessels. The serum immunoblot test for the detection of anticysticercal antibodies, performed in 15 of these 20 patients during a previous survey, were negative in 13 cases and the remaining two had a normal computed tomography of the head. This study suggests that NCC is not responsible for the increasing burden of stroke in rural areas of developing countries.

Incidence of convulsive epilepsy in a rural area in Kenya

Purpose

There are only a few studies of incidence of epilepsy in low and middle income countries (LMICs). These are often small and conducted in specific age groups or areas where the prevalence of risk factors is high; therefore, these studies are not representative of the wider populations. We determined the incidence of convulsive epilepsy (CE) in a large rural population in Kenya.

Methods

We conducted two cross‐sectional surveys 5 years apart within a health and demographic surveillance system. Initially we identified residents without epilepsy who were then reexamined in the follow‐up survey to determine incidence. We estimated the overall incidence of CE and incidence by age‐group, sex, and by administrative location. Estimates were adjusted for attrition during case identification and for the sensitivity of the screening method.

Key Findings

In a cohort of 151,408 people, 194 developed CE over the 5 years. The minimum crude incidence rate was 37.6/100,000 persons per year (95% confidence interval (CI) 32.7–43.3) and adjusted for loss to follow‐up, and the sensitivity of the survey methodology was 77.0/100,000 persons per year (95% CI 67.7–87.4). Incidence was highest in children 6–12 years (96.1/100,000 persons per year; 95% CI 78.4–117.9), and was lowest in the 29–49 year age group (37.4/100,000 persons per year; 95% CI 25.7–54.7).

Significance

We estimated a high incidence of convulsive epilepsy in this population. Incidence was highest early and late in life, suggesting that preventive interventions should target exposures that occur in these age groups. Incidence of focal epilepsy was more than twice that of generalized epilepsy, suggesting that etiologies that are amenable to intervention were most important in this population. It is likely that incidence is underestimated because of the early mortality of incident cases.

The incidence of human cysticercosis in a rural community of Eastern Zambia

A community-based longitudinal study was performed in the Eastern Province of Zambia, in which repeated serological samplings were done to determine the incidence of human cysticercosis. Three sampling rounds were carried out at six months intervals. A total of 867 participants presented for all three samplings. All samples were tested for the presence of cysticercus antigens using a monoclonal antibody-based enzyme-linked immunosorbent assay (sero-Ag-ELISA), while a randomly selected sub-sample of 161 samples from each sampling round was tested for specific antibodies using a commercial enzyme-linked immunoelectrotransfer blot (EITB) assay. Stool samples (n = 226) were also collected during the final round of sampling for taeniosis diagnosis by coprology and coproantigen ELISA. Cysticercosis seroprevalence varied from 12.2% to 14.5% (sero-Ag) and from 33.5% to 38.5% (sero-Ab) during the study period. A taeniosis prevalence of 11.9% was determined. Incidence rates of 6300 (sero-Ag, per 100000 persons-year) and 23600 (sero-Ab, per 100000 persons-year) were determined. Seroreversion rates of 44% for sero-Ag and 38.7% for sero-Ab were recorded over the whole period. In conclusion, this study has shown the dynamic nature of T. solium infections; many of the people at risk become (re)infected due to the high environmental contamination, with a high number turning seronegative within a year after infection. An important number of infections probably never fully establish, leading to transient antibody responses and short-term antigen presence.

The validation of a three-stage screening methodology for detecting active convulsive epilepsy in population-based studies in health and demographic surveillance systems

Background

There are few studies on the epidemiology of epilepsy in large populations in Low and Middle Income Countries (LMIC). Most studies in these regions use two-stage population-based screening surveys, which are time-consuming and costly to implement in large populations required to generate accurate estimates. We examined the sensitivity and specificity of a three-stage cross-sectional screening methodology in detecting active convulsive epilepsy (ACE), which can be embedded within on-going census of demographic surveillance systems.

We validated a three-stage cross-sectional screening methodology on a randomly selected sample of participants of a three-stage prevalence survey of epilepsy. Diagnosis of ACE by an experienced clinician was used as ‘gold standard’. We further compared the expenditure of this method with the standard two-stage methodology.

Results

We screened 4442 subjects in the validation and identified 35 cases of ACE. Of these, 18 were identified as false negatives, most of whom (15/18) were missed in the first stage and a few (3/18) in the second stage of the three-stage screening. Overall, this methodology had a sensitivity of 48.6% and a specificity of 100%. It was 37% cheaper than a two-stage survey.

Conclusion

This was the first study to evaluate the performance of a multi-stage screening methodology used to detect epilepsy in demographic surveillance sites. This method had poor sensitivity attributed mainly to stigma-related non-response in the first stage. This method needs to take into consideration the poor sensitivity and the savings in expenditure and time as well as validation in target populations. Our findings suggest the need for continued efforts to develop and improve case-ascertainment methods in population-based epidemiological studies of epilepsy in LMIC.

Cestode infestations: hydatid disease and cysticercosis

Although humans can be definitive hosts for cestodes (tapeworms), major pathologic conditions occur during cestode larval stages when humans serve as the intermediate host for these parasites. The most relevant forms of human disease caused by cestode larvae are echinococcosis, caused by Echinococcus granulosus (cystic echinococcosis) and Echinococcus multilocularis (alveolar echinococcosis), and cysticercosis, caused by Taenia solium. These infections occur worldwide, but their relevance is particularly high in developing countries, where poor hygiene conditions facilitate the transmission of the parasites. The therapeutic approach is often complex, requiring surgery and/or chemotherapy or, in the case of cystic echinococcosis, percutaneous treatments.

Cognitive changes and quality of life in neurocysticercosis: a longitudinal study

BACKGROUND

Few studies have focused on the cognitive morbidity of neurocysticercosis (NCC), one of the most common parasitic infections of the central nervous system. We longitudinally assessed the cognitive status and quality of life (QoL) of patients with incident symptomatic NCC cases and matched controls.

METHODOLOGY/PRINCIPAL FINDINGS

The setting of the study was the Sabogal Hospital and Cysticercosis Unit, Department of Transmissible Diseases, National Institute of Neurological Sciences, Lima, Peru. The design was a longitudinal study of new onset NCC cases and controls. Participants included a total of 14 patients with recently diagnosed NCC along with 14 healthy neighborhood controls and 7 recently diagnosed epilepsy controls. A standardized neuropsychological battery was performed at baseline and at 6 months on NCC cases and controls. A brain MRI was performed in patients with NCC at baseline and 6 months. Neuropsychological results were compared between NCC cases and controls at both time points. At baseline, patients with NCC had lower scores on attention tasks (p<0.04) compared with epilepsy controls but no significant differences compared to healthy controls. Six months after receiving anti-parasitic treatment, the NCC group significantly improved on tasks involving psychomotor speed (p<0.02). QoL at baseline suggested impaired mental function and social function in both the NCC and epilepsy group compared with healthy controls. QoL gains in social function (p=0.006) were noted at 6 months in patients with NCC.

CONCLUSIONS/SIGNIFICANCE

Newly diagnosed patients with NCC in this sample had mild cognitive deficits and more marked decreases in quality of life at baseline compared with controls. Improvements were found in both cognitive status and quality of life in patients with NCC after treatment.

Diagnosis and treatment of neurocysticercosis

Neurocysticercosis is a parasitic disease caused by the larval (cystic) form of the pork cestode tapeworm, Taenia solium, and is a major cause of acquired seizures and epilepsy worldwide. Development of sensitive and specific diagnostic methods, particularly CT and MRI, has revolutionized our knowledge of the burden of cysticercosis infection and disease, and has led to the development of effective antihelminthic treatments for neurocysticercosis. The importance of calcified granulomas with perilesional edema as foci of seizures and epilepsy in populations where neurocysticercosis is endemic is newly recognized, and indicates that treatment with anti-inflammatory agents could have a role in controlling or preventing epilepsy in these patients. Importantly, neurocysticercosis is one of the few diseases that could potentially be controlled or eliminated-an accomplishment that would prevent millions of cases of epilepsy. This Review examines the rationale for treatment of neurocysticercosis and highlights the essential role of inflammation in the pathogenesis of disease, the exacerbation of symptoms that occurs as a result of antihelminthic treatment, and the limitations of current antihelminthic and anti-inflammatory treatments.

Incidence of epilepsy: a systematic review and meta-analysis

OBJECTIVE

To estimate the pooled incidence of epilepsy from published studies and investigate sources of heterogeneity in the estimates.

METHODS

We searched online databases for incidence studies and used meta-analytic methods to analyze the data.

RESULTS

Thirty-three articles met the entry criteria. The median incidence of epilepsy was 50.4/100,000/year (interquartile range [IQR] 33.6-75.6), while it was 45.0 (IQR 30.3-66.7) for high-income countries and 81.7 (IQR 28.0-239.5) for low- and middle-income countries. Population-based studies had higher incidence estimates than hospital-based studies (p = 0.02) while retrospective study design was associated with lower estimates than prospective studies (p = 0.04).

CONCLUSION

We provide data that could potentially be used to assess the burden and analyze the trends in incidence of epilepsy. Our results support the need for large population-based incidence studies of epilepsy.

Multicultural challenges in epilepsy

Epilepsy is a common neurological condition throughout the world. Its care involves medical expertise, but may also bring different cultural challenges. We discuss clinical, social and psychological outcomes in different cultural settings. We point out differences and similarities in epilepsy epidemiology (etiology and risk factors, prognosis, and natural history), disparities in care and health services, and cultural influences and traditional beliefs, with special respect to practical issues and possible transcultural misunderstandings. We also discuss the relevance of multicultural issues to clinicians working in developed countries.