Epilepsy, cysticercosis, and toxocariasis: a population-based case-control study in rural Bolivia

Seroprevalence of human toxocariasis in Latin America and the Caribbean: a systematic review and meta-analysis

Introduction

The current study aimed to quantitatively synthesize available evidence regarding the seroprevalence of human toxocariasis in Latin America and the Caribbean.

Methods

A systematic research involving six electronic databases was conducted using a research strategy that combined MeSH terms with free terms. Article selection and information extraction were performed using a double and independent approach. The Newcastle-Ottawa tool was used to assess the risk of bias in the included articles. The meta-analysis used the random-effects approach, with subgroup analysis and sensitivity analysis for risk of bias also being performed.

Results

We included 101 articles with a total of 31,123 participants. The studies were conducted between 1990 and 2022, with Brazil accounting for the largest number of studies (n = 37). The overall seroprevalence of human toxocariasis was 31.0% (95% CI: 27.0-35.0%, I2 = 99%). The prevalence of the main characteristics observed in seropositive patients were as follows: ocular toxocariasis (30.0%), asymptomatic (26.0%), and presence of dogs at home (68.0%). In addition, the seroprevalence was lower in studies including only adults than in those including children or both. In contrast, no differences in seroprevalences were found between studies conducted in the community and hospital.

Conclusion

The overall seroprevalence of human toxocariasis in Latin America and the Caribbean was high. Notably, our findings showed that the seroprevalence was increased among populations who kept a dog at home but was decreased in populations comprising only adults. Our findings can be used to establish epidemiological surveillance strategies for the prevention and early identification of toxocariasis.

Long-Standing International Cooperation in Parasitology Research: A Summary of 35 Years of Activities in the Bolivian Chaco

The Bolivian Chaco is a semiarid region with a low population density, situated in the southeast part of the Plurinational State of Bolivia. Here, despite the improvements of the last 15 years, poverty remains high in rural areas, where social vulnerability is widespread. The Guaraní ethnic group often lives in isolated communities with a low standard of hygiene and sanitation. This epidemiological scenario favors the spread of transmissible diseases, including several parasitic infections belonging to the neglected tropical diseases (NTDs) group. In this area, a long-standing research activity, built upon the synergism between local and foreign institutions, has been established since the late 1980s and helps to fill in the knowledge gap about the epidemiology dynamics of soil-transmitted helminths, vector-borne parasites, and other parasitic diseases. A 35-year history of cooperation programs in parasitology research has contributed to informing local health authorities of the NTD burden in the Bolivian Chaco and, ultimately, supports local healthcare providers in the management of parasitic diseases.

Case-Control Study to Assess the Association between Epilepsy and Toxocara Infection/Exposure

Although causes and etiology of epilepsy are mostly obscure, some zoonotic parasites, such as Toxocara species, have been proposed as a risk factor for this disease. Here, we conducted an age-matched case-control study to evaluate whether there is an association between epilepsy and the presence of serum antibodies to Toxocara in incident cases. We included 94 idiopathic epileptic patients as cases, and—from the same geographical region—88 people with no own history of epilepsy or neurological disease as control subjects. Epilepsy was confirmed by a physician using the International League Against Epilepsy (ILAE) definition. All participants were screened for the anti-Toxocara IgG serum antibody by enzyme-linked immunosorbent assay (ELISA). Univariate and mutltivariate statistical analyses were applied to calculate the crude and adjusted odds ratios (OR) and 95% confidence intervals (CIs). Anti-Toxocara serum antibody was detected in 37 epileptic patients and in 23 control subjects, giving respective seroprevalences of 39.3% (95% CI, 29.4–49.9%) and 26.1% (95% CI, 17.3–36.5%), respectively. Adjusted multivariate logistic regression analysis estimated an OR of 2.38 (95% CI, 1.25–4.63), indicating a significant association between epilepsy and Toxocara seropositivity. There was also a significant association between seropositivity to Toxocara and partial (OR, 2.60; 95% CI, 1.14–6.04) or generalized (OR, 2.17; 95% CI, 1.09–4.40%) seizures. Findings from the present study of incident epileptic cases support previous studies proposing that Toxocara infection/exposure is a risk factor for epilepsy. However, further well-designed population-based surveys and mechanistic/experimental studies in animal models are required to better understand the reason(s) for this association.

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.

Zoonotic and vector-borne parasites and epilepsy in low-income and middle-income countries

Zoonotic and vector-borne parasites are important preventable risk factors for epilepsy. Three parasitic infections - cerebral malaria, Taenia solium cysticercosis and onchocerciasis - have an established association with epilepsy. Parasitoses are widely prevalent in low-income and middle-income countries, which are home to 80% of the people with epilepsy in the world. Once a parasitic infection has taken hold in the brain, therapeutic measures do not seem to influence the development of epilepsy in the long term. Consequently, strategies to control, eliminate and eradicate parasites represent the most feasible way to reduce the epilepsy burden at present. The elucidation of immune mechanisms underpinning the parasitic infections, some of which are parasite-specific, opens up new therapeutic possibilities. In this Review, we explore the pathophysiological basis of the link between parasitic infections and epilepsy, and we consider preventive and therapeutic approaches to reduce the burden of epilepsy attributable to parasitic disorders. We conclude that a concerted approach involving medical, veterinary, parasitological and ecological experts, backed by robust political support and sustainable funding, is the key to reducing this burden.

Decline in Total Serum IgE and Soluble CD30 in the Context of Soil-Transmitted Helminth Decline in Bolivia

In the Bolivian Chaco, recent surveys documented a dramatic decrease in the prevalence of soil-transmitted helminth (STH) infections as compared with the 1980s after thirty years of preventive chemotherapy (PC). Concomitant immunological rearrangements are expected. Because nematode infections are associated with increased levels of circulating IgE and glycoprotein CD30 soluble form (sCD30), this study aims to evaluate changes in serological markers of T helper (Th)2-cells activity between 1987 (high STH prevalence) and 2013 (low STH prevalence) in rural communities in the Bolivian Chaco area. We collected 151 sera during two different surveys in 1987 (n = 65) and 2013 (n = 86) and measured the concentration of total IgE and sCD30 by immunoassays. We found a statistically significant age-independent decrease in the total IgE (P < 0.0001) and sCD30 (P < 0.0001) from 1987 to 2013. The significant decrease in serological Th2 markers (IgE and sCD30) between 1987 and 2013 is consistent with the drop in STH prevalence in this geographical area during the same period of time. Further studies might elucidate the clinical and epidemiological impact of these serological rearrangements.

Microsurgical Treatment of Epilepsy with Parenchymal Neurocysticercosis

Parenchymal neurocysticercosis is the most common form of neurocysticercosis in the central nervous system (CNS), which mainly causes epilepsy and usually responses well to routine medications. However, there are appreciable cases of relapses refractory to medical treatment. We investigated microsurgical treatment of epilepsy with parenchymal neurocysticercosis. Nine cases of epilepsy caused by parenchymal neurocysticercosis from 2002 to 2018 were analyzed retrospectively. Cysts in 7 cases were completely removed. No case died of operation and no new dysfunction of the nervous system was observed after surgery. Among the other 9 cases, 8 cases became seizure-free or controlled by medicine according to the postoperative follow-up for 6 months to 9 years. One case was lost for follow-up. It was suggested that epilepsy with parenchymal neurocysticercosis can usually be controlled after routine medications. However, surgery is still indicated in some cases and careful microsurgery is associated with satisfactory clinical outcomes in appropriately selected cases.

Frequency of Toxocara canis antibodies in Mexican paediatric patients with epilepsy

The relationship between epilepsy and the presence of visceral larva migrans caused by Toxocara canis in Mexican children remains uncertain; however, this relationship needs to be elucidated because these parasite larvae can invade the human central nervous system. Accordingly, this study aimed to determine the frequency and specificity of anti-T. canis antibodies in the sera of children with epilepsy to determine the relationship between this parasite and epilepsy. The sera samples of 214 children were examined: 111 children diagnosed with epilepsy and 103 clinically healthy children without neurological disorders. In the sera of each group, the presence and specificity of anti-T. canis and anti-Ascaris lumbricoides antibodies, as well as the cross-reactivity between them, were assessed using enzyme-linked immunosorbent assay and Western blotting analysis. Among the children with epilepsy, 25.2% exhibited seropositivity to T. canis. Cross-reactivity against the A. lumbricoides antigen was present in 46.8% of the children with epilepsy, whereas 11.7% of the children with epilepsy and anti-T. canis antibodies did not exhibit cross-reactivity against this antigen. The Western blotting analysis of the sera from the children with epilepsy demonstrated the presence of T. canis proteins, with molecular weights of 24, 35, 55, 70, 120 and 210 kDa, and A lumbricoides proteins with molecular weights of 70, 80 and 110 kDa. Our results revealed the presence of anti-T. canis antibodies in the children with epilepsy; furthermore, cross-reactivity tests with A. lumbricoides showed the importance of the presence of anti-T. canis antibodies in revealing the relationship between this parasite and epilepsy in children.

Prevalence of Epilepsy and its Association with Exposure to Toxocara canis: A Community Based, Case-control Study from Rural Northern India

Objectives:

Many community-based and hospital-based studies across the world have yielded contradictory results regarding association of positive Toxocara canis serology and epilepsy. The present study was planned to analyze disease burden of epilepsy in rural community of North India and its association with exposure to T. canis in this part of the world.

Methods:

A door-to-door screening survey was carried out in the rural community using a validated questionnaire for epilepsy by trained field workers, which was finally confirmed by trained neurologists. The risk factors for epilepsy and for predisposing infections were also enquired. The results were compared with an equal number of age- and sex-matched healthy controls enrolled from the same community. Serologic evaluation was carried out to detect antibodies against T. canis.

Results:

A total of 41,973 persons from the rural community in 49 villages were enrolled in the study. Two hundred and eleven persons were confirmed to be suffering from active epilepsy, resulting in a crude prevalence of 5 per 1000 population. More than 50% of people with epilepsy were in the second or third decade of life. The prevalence of antibodies to T. canis was similar in people with epilepsy (13.7%; 29 of 211 individuals) and controls (9.95%; 21 of 211 individuals). Of the 151 persons with epilepsy, who underwent CT scan, 34 people (22.3%) had evidence of inflammatory granuloma, thereby confirming high incidence of this infestation in rural Northern India.

Significance:

Our study does not support the association between epilepsy and exposure to T. canis in rural Northern Indian population.

Updated evidence of the association between toxocariasis and epilepsy: Systematic review and meta-analysis

Objective

To gain further insight on the association between human toxocariasis and epilepsy in light of the new evidence in the last years.

Methods

A systematic review was conducted without date and language restriction in the following electronic databases: MEDLINE (PubMed), Ingenta Connect, Science Direct (Elsevier), RefDoc, Scopus, HighWire, Scielo and the database of the Institute of Neuroepidemiology and Tropical Neurology of the Limoges University (IENT). Two investigators independently conducted the search up to November 2017. A pooled odds ratio (OR) was estimated using a random effects model. Meta-regression was conducted to investigate potential sources of heterogeneity.

Results

Database search produced 204 publications. Eleven case-control studies were included that were carried out in 13 countries worldwide. A total number of 4740 subjects were considered (2159 people with epilepsy and 2581 people without epilepsy). The overall pooled OR was 1.69 (95% CI 1.42–2.01) for the association between epilepsy and Toxocara spp. seropositivity. A positive association was constantly reported in the restricted analysis (WB as confirmatory or diagnostic test, younger population, and population–based studies). Meta-regression showed no statistically significant association between covariates and outcome.

Conclusion

The updated meta-analysis provides epidemiological evidence of a positive association between Toxocara seropositivity and epilepsy. New surveys supported the association, mainly population-based studies. On this basis, health strategies to reduce the impact of Toxocara spp are strongly advised. Further research should be performed to understand the physiopathological mechanisms of toxocara-associated epileptogenesis.

Human toxocariasis is a parasitic zoonosis caused by the larval stages of Toxocara canis (T. canis), the common roundworm of dogs, and by the roundworm of cats, Toxocara cati (T. cati). Toxocariasis is one of the most prevalent helminthiasis worldwide. Humans become infected by the ingestion of contaminated food or soil or by direct contact with dogs and cats. Epilepsy is the most common chronic neurological disorder worldwide with a global estimate of about 70 million cases of lifetime epilepsy. Early studies suggested high rate of toxocara exposure (toxocara seropositivity) among people with epilepsy. Despite several studies support the possible role of toxocariasis in the incidence of epilepsy, this association is still debated. We updated our previous research to gain further insight on the association. This study provides new evidence of a positive association between the two diseases. On this basis, health strategies to reduce the impact of Toxocara spp are strongly advised. Further studies are necessary to clarify the role of certain parasites in epilepsy.

Systematic review and meta-analysis estimating association of cysticercosis and neurocysticercosis with epilepsy

Background

We reviewed studies that analyzed cysticercosis (CC), neurocysticercosis (NCC) and epilepsy across Latin America, Asia and Sub-Saharan Africa, to estimate the odds ratio and etiologic fraction of epilepsy due to CC in tropical regions.

Methodology

We conducted a systematic review of the literature on cysticercosis and epilepsy in the tropics, collecting data from case-control and cross-sectional studies. Exposure criteria for CC included one or more of the following: serum ELISA or EITB positivity, presence of subcutaneous cysts (both not verified and unverified by histology), histology consistent with calcified cysts, and brain CT scan consistent with NCC. A common odds-ratio was then estimated using meta-analysis.

Principal findings

37 studies from 23 countries were included (n = 24,646 subjects, 14,934 with epilepsy and 9,712 without epilepsy). Of these, 29 were case-control (14 matched). The association between CC and epilepsy was significant in 19 scientific articles. Odds ratios ranged from 0.2 to 25.4 (a posteriori power 4.5–100%) and the common odds ratio was 2.7 (95% CI 2.1–3.6, p <0.001). Three subgroup analyses performed gave odds ratios as: 2.2 (EITB-based studies), 3.2 (CT-based studies), 1.9 (neurologist-confirmed epilepsy; door-to-door survey and at least one matched control per case). Etiologic fraction was estimated to be 63% in the exposed group among the population.

Significance

Despite differences in findings, this meta-analysis suggests that cysticercosis is a significant contributor to late-onset epilepsy in tropical regions around the world, and its impact may vary depending on transmission intensity.

Cysticercosis is a helminthic infection of the central nervous system (CNS) and the leading cause of late onset epilepsy in low-and middle-income countries. This neurological disease is a public health problem in Sub-Saharan Africa, Asia and Latin America, affecting impoverished rural and peri-urban populations where sanitation is inadequate. Diagnostic criteria for NCC vary according to regional availability and access to imaging and serological tests. This systematic review highlights the lack of appropriate methodology in most observational studies, with few studies including control groups, a basic epidemiological criteria needed to demonstrate an association. EITB for cysticercosis was widely used to measure exposure, and brain CT scan was a non-invasive alternative used to identify cysts. Neurocysticercosis (NCC) is a preventable neurological condition in the tropics despite resource limitations in LMIC regions. Well-designed studies are needed to provide quality evidence to support control interventions and surveillance systems for this important zoonotic disease.

Seropositivity of Toxoplasma gondii and Toxocara spp. in Children with Cryptogenic Epilepsy, Benha, Egypt

The present study aimed to investigate the possible association of Toxoplasma gondii and Toxocara spp. infections with cryptogenic epilepsy in children. The study was carried out between June 2014 and March 2015. Total 90 children (40 with cryptogenic epilepsy, 30 with non-cryptogenic epilepsy, and 20 healthy control children) were evaluated to determine the anti-Toxocara and anti-T. gondii IgG seropositivity using ELISA kits. Epileptic cases were selected from those attending the pediatrics outpatient clinic of Benha University Hospital, Pediatrics Neurology Unit, and from Benha Specialized Hospital of children. The results showed that the level of anti-T. gondii IgG seropositivity was significantly higher among children with cryptogenic epilepsy (20%) than among children with non-cryptogenic children (0%). In healthy controls (10%), there was no association between toxocariasis seropositivity and cryptogenic epilepsy (only 5.7%; 4 out of 70 cases) among cases and 10% (2 out of 20) among controls. Among toxocariasis IgG positive cases, 3 (7.5%) were cryptogenic, and only 1 (3.3%) was non-cryptogenic. These statistically significant results support the association between T. gondii infection and cryptogenic epilepsy while deny this association with toxocariasis.

Dramatic decrease in prevalence of soil-transmitted helminths and new insights into intestinal protozoa in children living in the Chaco region, Bolivia

We assessed the prevalence of intestinal parasites among 268 2-12-year-old children living in rural areas, small villages, and semi-urban areas of the Chaco region, south-eastern Bolivia. The overall parasitism was 69%. Only protozoa, helminths, or co-infections were observed in 89.2%, 5.9%, or 4.9% of the positive children, respectively. A significant progressive increase in overall parasite prevalence was found when passing from rural areas to small villages and semi-urban areas. The most commonly found species were Entamoeba coli (38.4%), Giardia intestinalis (37.7%), and Blastocystis spp. (16%). Hymenolepis nana was the most prevalent helminth (5.6%), followed by Ascaris lumbricoides and hookworms (1.5% and 0.4%) evidenced only in rural areas and in villages. Molecular diagnostics identified Blastocystis subtypes 9 and 2, and 5 infections by Entamoeba histolytica and 4 by Entamoeba dispar. The dramatic decrease in prevalence of soil-transmitted helminths with respect to that observed about 20 years ago (> 40%) evidences the success of the preventive chemotherapy intervention implemented in 1986. Health education and improved sanitation should be intensified to control protozoan infections.

Epidemiology, causes, and treatment of epilepsy in sub-Saharan Africa

SUMMARY

Epilepsy is a common neurological disease in tropical countries, particularly in sub-Saharan Africa. Previous work on epilepsy in sub-Saharan Africa has shown that many cases are severe, partly a result of some specific causes, that it carries a stigma, and that it is not adequately treated in many cases. Many studies on the epidemiology, aetiology, and management of epilepsy in sub-Saharan Africa have been reported in the past 10 years. The prevalence estimated from door-to-door studies is almost double that in Asia, Europe, and North America. The most commonly implicated risk factors are birth trauma, CNS infections, and traumatic brain injury. About 60% of patients with epilepsy receive no antiepileptic treatment, largely for economic and social reasons. Further epidemiological studies should be a priority to improve understanding of possible risk factors and thereby the prevention of epilepsy in Africa, and action should be taken to improve access to treatment.

Exposure to multiple parasites is associated with the prevalence of active convulsive epilepsy in sub-Saharan Africa

Background

Epilepsy is common in developing countries, and it is often associated with parasitic infections. We investigated the relationship between exposure to parasitic infections, particularly multiple infections and active convulsive epilepsy (ACE), in five sites across sub-Saharan Africa.

Methods and Findings

A case-control design that matched on age and location was used. Blood samples were collected from 986 prevalent cases and 1,313 age-matched community controls and tested for presence of antibodies to Onchocerca volvulus, Toxocara canis, Toxoplasma gondii, Plasmodium falciparum, Taenia solium and HIV. Exposure (seropositivity) to Onchocerca volvulus (OR = 1.98; 95%CI: 1.52–2.58, p<0.001), Toxocara canis (OR = 1.52; 95%CI: 1.23–1.87, p<0.001), Toxoplasma gondii (OR = 1.28; 95%CI: 1.04–1.56, p = 0.018) and higher antibody levels (top tertile) to Toxocara canis (OR = 1.70; 95%CI: 1.30–2.24, p<0.001) were associated with an increased prevalence of ACE. Exposure to multiple infections was common (73.8% of cases and 65.5% of controls had been exposed to two or more infections), and for T. gondii and O. volvulus co-infection, their combined effect on the prevalence of ACE, as determined by the relative excess risk due to interaction (RERI), was more than additive (T. gondii and O. volvulus, RERI = 1.19). The prevalence of T. solium antibodies was low (2.8% of cases and 2.2% of controls) and was not associated with ACE in the study areas.

Conclusion

This study investigates how the degree of exposure to parasites and multiple parasitic infections are associated with ACE and may explain conflicting results obtained when only seropositivity is considered. The findings from this study should be further validated.

The prevalence of epilepsy is greater in developing countries compared to developed countries, and parasitic infestations are thought to contribute to this increased burden. We conducted a case-control study across five sites in sub-Saharan Africa to investigate the relationship between epilepsy and exposure to parasitic infections, and the association between epilepsy and multiple co-incidental infections. Exposure to Onchocerca volvulus, Toxocara canis and Toxoplasma gondii as well as high antibody levels (top tertile) to Toxocara canis was positively associated with the prevalence of active convulsive epilepsy (ACE). Multiple co-incidental parasitic infections were common, and the combined effect of T. gondii and O. volvulus co-infection on ACE was greater than the sum of the individual effects. The contribution of each of these parasitic infections on the burden of epilepsy in sub-Saharan Africa should be explored.

Seroprevalence of toxoplasmosis, toxocariasis and cysticercosis in a rural settlement, São Paulo State, Brazil

BACKGROUND

The goal of this study was to estimate the seroprevalence of Toxocara spp., Toxoplasma gondii, and Taenia solium metacestode infection and determine some of the associated risk factors for people living in the Dona Carmen settlement, Pontal of Paranapanema, São Paulo, Brazil.

METHODS

Serum samples from 194 subjects were tested and participants answered a questionnaire. An enzyme-linked immunosorbent assay (ELISA) system based on Toxocara spp. excretory-secretory antigens obtained from the cultured second-stage larvae of Toxocara canis or vesicular fluid (VF) antigen from Taenia crassiceps metacestode was used to detect anti-Toxocara spp. IgG and IgE and anti-T. solium metacestode, respectively. For cysticercosis, the reactive ELISA samples were assayed by Western blotting using 18 kDa and 14 kDa proteins purified from VF. For T. gondii-specific IgG and IgM antibodies, anti-SAG-1, GRA-1, and GRA-7 epitope specificity was determined by ELISA.

RESULTS

Toxoplasma gondii IgG antibodies were found in 102/194 individuals (52·6%) with increased infections in females (P = 0·02) and those with ≤US$300 monthly income (P = 0·01). Positive IgM antibodies were detected in 21/194 individuals (10·8%). Antibodies specific to Toxocara spp. were found in 28/194 subjects (14·4%). All the individuals with Toxocara spp. also had T. gondii-specific IgG antibodies. Taenia solium metacestode antibodies were detected in 11 subjects (5·7%), but none were reactive based on Western blotting.

CONCLUSION

In spite of environmental, educational, and socioeconomic factors favoring parasite infection, the seropositivity rates of T. gondii, Toxocara spp., and T. solium metacestode-specific IgG antibodies are similar to the rates found in studies conducted in different populations in Brazil.

Investigation of anti-Toxocara antibodies in epileptic patients and comparison of two methods: ELISA and Western blotting

The relationship between Toxocara infection and epilepsy was previously demonstrated by several case-control studies and case reports. These previous studies were often based on the enzyme-linked immunosorbent assay (ELISA) using Toxocara excretory-secretory antigens, which are not specific due to cross-reactivity with other parasitic infections such as ascariasis, trichuriasis, and anisakiasis. An immunoblot analysis is highly specific and can detect low levels of Toxocara antibodies. Therefore, this assay may be useful in the identification of toxocariasis in epileptic patients. We examined patients who had epilepsy and healthy subjects for seropositivity for Toxocara infection by ELISA and Western blotting. Out of 85 epileptic patients, 10 (11.8%) and 3 (3.5%) persons exhibited Toxocara immunoglobulin G (IgG) antibodies responses by ELISA and by both techniques, respectively. Moreover, in the healthy group (n = 85), 3 (3.5%) persons were positive by ELISA, but none was detected by Western blotting. This study indicates that Toxocara infection is a risk factor for epilepsy in Iran. These findings strongly suggest the need to perform Western blotting immunodiagnosis, as well as the ELISA using Toxocara excretory-secretory antigens, to improve diagnosis of human toxocariasis in patients with epilepsy.

Association between epilepsy and cysticercosis and toxocariasis: a population-based case-control study in a slum in India

PURPOSE

To assess the association between epilepsy and exposure to the parasites, Toxocara canis and Taenia solium in a slum-community in India.

METHODS

A door-to-door survey to determine the prevalence of epilepsy was carried out by trained field workers. For every case, one age- and gender-matched control was selected from the same community. Serologic evaluation was carried out to detect antibodies against T. canis and T. solium.

KEY FINDINGS

The crude prevalence of active epilepsy was 7.2 per 1,000. We enrolled 114 people with active epilepsy and 114 controls. The prevalence of antibodies to T. canis was similar in people with active epilepsy (4.7%; 5 of 106 people) and in controls (5.7%; 6 of 106 people). The prevalence of antibodies to T. solium was 25.5% (27 of 106) in people with active epilepsy, significantly higher than in controls (12.3%; 13 of 106 cases; p = 0.02). Adjusted conditional (fixed-effects) logistic regression estimated an odds ratio of 2.8 (95% confidence interval 1.2-6.8) for detection of T. solium antibodies. Nineteen people with active epilepsy demonstrated evidence of neurocysticercosis (NCC) on magnetic resonance imaging (MRI), including 7 (36.5%) with solitary cysticercus granuloma.

SIGNIFICANCE

Our findings do not support an association between epilepsy and exposure to T. canis in the community studied. A significant association between T. solium exposure and epilepsy was observed. Of those with active epilepsy and evidence of NCC on MRI, a large proportion demonstrated solitary cysticercus granuloma.

Prevalence case-control study of epilepsy in three Burkina Faso villages

PURPOSE

To estimate the association between the prevalence of epilepsy and potential risk factors in three Burkina Faso villages.

METHODS

Three villages were selected based on local reports of high numbers of epilepsy cases and pig-rearing practices. One person aged 7 or older was selected at random from all households of selected concessions for epilepsy screening and blood sampling. Epilepsy was confirmed by a physician using the ILAE definition. The cross-sectional associations between epilepsy and selected factors and seroresponse to the antigens of Taenia solium were estimated using a Bayesian hierarchical logistic regression. Prevalence odds ratios (POR) and their 95% Bayesian Credible Intervals (95% BCI) were estimated.

RESULTS

Of 888 individuals interviewed, 39 of 70 screened positive were confirmed to have epilepsy for a lifetime prevalence of 4.5% (95% CI: 3.3; 6.0). The prevalence of epilepsy was associated with a positive reaction to cysticercosis Ag-ELISA serology (POR = 3.1, 95% BCI = 1.0; 8.3), past pork consumption (POR = 9.7, 95% BCI = 2.5; 37.9), and being salaried or a trader compared to a farmer or housewife (POR = 2.9, 95% BCI = 1.2; 6.4).

DISCUSSION

Several factors were associated with prevalent epilepsy, with Ag-ELISA suggesting the presence of neurocysticercosis. The association between epilepsy and some occupations may reflect differences in local attitudes toward epilepsy and should be further explored.

Toxocariasis and epilepsy: systematic review and meta-analysis

Objective

Human toxocariasis is a zoonotic infection caused by the larval stages of Toxocara canis (T. canis) and less frequently Toxocara cati (T. cati). A relationship between toxocariasis and epilepsy has been hypothesized. We conducted a systematic review and a meta-analysis of available data to evaluate the strength of association between epilepsy and Toxocara spp. seropositivity and to propose some guidelines for future surveys.

Data Sources

Electronic databases, the database from the Institute of Neuroepidemiology and Tropical Neurology of the University of Limoges (http://www-ient.unilim.fr/) and the reference lists of all relevant papers and books were screened up to October 2011.

Methods

We performed a systematic review of literature on toxocariasis (the exposure) and epilepsy (the outcome). Two authors independently assessed eligibility and study quality and extracted data. A common odds ratio (OR) was estimated using a random-effects meta-analysis model of aggregated published data.

Results

Seven case-control studies met the inclusion criteria, for a total of 1867 participants (850 cases and 1017 controls). The percentage of seropositivity (presence of anti-Toxocara spp. antibodies) was higher among people with epilepsy (PWE) in all the included studies even if the association between epilepsy and Toxocara spp. seropositivity was statistically significant in only 4 studies, with crude ORs ranging 2.04–2.85. Another study bordered statistical significance, while in 2 of the included studies no significant association was found. A significant (p<0.001) common OR of 1.92 [95% confidence interval (CI) 1.50–2.44] was estimated. Similar results were found when meta-analysis was restricted to the studies considering an exclusively juvenile population and to surveys using Western Blot as confirmatory or diagnostic serological assay.

Conclusion

Our results support the existence of a positive association between Toxocara spp. seropositivity and epilepsy. Further studies, possibly including incident cases, should be performed to better investigate the relationship between toxocariasis and epilepsy.

Human toxocariasis is an infection caused by the larval stage of the worms Toxocara canis and less frequently Toxocara cati, common parasites of domestic and peridomestic dogs and cats. It is a cosmopolitan infection, occurring whenever the man-soil-dog relationship is particularly close, especially in tropical countries, where the humid climate favours the survival of parasite eggs in the soil, and in rural settings, where the poor hygiene increases the probability of human infection. Epilepsy affects nowadays at least 65 million of people worldwide and is particularly common in tropical areas, probably because of the presence of cases caused by infectious diseases largely absent in industrialized countries. For several decades, researchers have investigated the possible association between toxocariasis and epilepsy. In this study we conducted a statistical analysis of all the data available on the relationship between these two conditions. The combined results of the 7 studies included indicate an association between the two diseases. Further studies are necessary to demonstrate a causal relationship (i.e. toxocariasis causes epilepsy). Considering that toxocariasis is a preventable and common disease, a better understanding of the relationship between toxocariasis and epilepsy may contribute to improving prevention of epilepsy worldwide.

The highly antigenic 53/25 kDa Taenia solium protein fraction with cathepsin-L like activity is present in the oncosphere/cysticercus and induces non-protective IgG antibodies in pigs

Cathepsin L-like proteases are secreted by several parasites including Taenia solium. The mechanism used by T. solium oncospheres to degrade and penetrate the intestine and infect the host is incompletely understood. It is assumed that intestinal degradation is driven by the proteolytic activity of enzymes secreted by the oncosphere. Blocking the proteolytic activity by an antibody response would prevent the oncosphere penetration and further infection. Serine and cysteine proteases including chymotrypsin, trypsin, elastase, and cathepsin L, are secreted by T. solium and Taenia saginata oncospheres when cultured in vitro, being potential vaccine candidates. However, the purification of a sufficient quantity of proteases secreted by oncospheres to conduct a vaccine trial is costly and lengthy. A 53/25 kDa cathepsin L-like fraction partially purified from T. solium cyst fluid was described previously as an important antigen for immunodiagnostics. In this study we found that this antigen is present in the T. solium oncosphere and is also secreted by the cysticercus. This protein fraction was tested for its ability to protect pigs against an oral challenge with T. solium oncospheres in a vaccine trial. IgG antibodies against the 53/25 kDa cathepsin L-like protein fraction were elicited in the vaccinated animals but did not confer protection.

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.

Immunoinformatics prediction of linear epitopes from Taenia solium TSOL18

Cysticercosis is a public health problem in several developing countries. The oncosphere protein TSOL18 is the most immunogenic and protective antigen ever reported against porcine cysticercosis, although no specific epitope has been identified to account for these properties. Recent evidence suggests that protection might be associated with conformational epitopes. Linear epitopes from TSOL18 were computationally predicted and evaluated for immunogenicity and protection against porcine cysticercosis. A synthetic peptide was designed based on predicted linear B cell and T cell epitopes that are exposed on the surface of the theoretically modeled structure of TSOL18. Three surface epitopes from TSOL18 were predicted as immunogenic. A peptide comprising a linear arrangement of these epitopes was chemically synthesized. The capacity of the synthetic peptide to protect pigs against an oral challenge with Taenia solium proglottids was tested in a vaccine trial. The synthetic peptide was able to produce IgG antibodies in pigs and was associated to a reduction of the number of cysts, although was not able to provide complete protection, defined as the complete absence of cysts in necropsy. This study demonstrated that B cell and T cell predicted epitopes from TSOL18 were not able to completely protect pigs against an oral challenge with Taenia solium proglottids. Therefore, other linear epitopes or eventually conformational epitopes may be responsible for the protection conferred by TSOL18.

Understanding the differences in prevalence of epilepsy in tropical regions

Epilepsy is a frequent chronic neurologic disorder that affects nearly 70 million people worldwide. The majority of people with epilepsy live in developing countries, where epilepsy remains a major public health problem. Wide prevalence differences exist among various populations across sub-Saharan Africa, Latin America, and Asia. In particular, prevalence is lower in Southeast Asia than in sub-Saharan Africa and Latin America. Methodologic problems alone do not seem to explain these differences shown in recent review papers. The distribution of numerous risk or etiologic factors such as infectious diseases with neurologic sequel, head injuries, or genetic factors could explain these differences. Stigmatization of people with epilepsy could lead to underestimating the prevalence of epilepsy, even in well-conducted studies. It is important to standardize the process of epidemiologic monitoring of epilepsy in order to improve the reliability in data comparison. Understanding the reasons for these differences is a crucial issue for eventually raising new hypotheses or prevention strategies.

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.

Emerging zoonoses in the southern United States: toxocariasis, bovine tuberculosis and southern tick-associated rash illness

The majority of emerging diseases in humans have been linked to zoonotic pathogens originating in domestic animals or wildlife. This is a public health concern because zoonotic infections affect several aspects of the society. The complex interactions among pathogen, host and environment also pose challenges in estimating the true burden of those infections. However, the recent development of new molecular diagnostic tools has allowed for better diagnosis of zoonotic infections. This review focuses on 3 emerging zoonoses, namely toxocariasis, bovine tuberculosis and southern tick-associated rash illness, and demonstrates that these infections may be more prevalent in the southern United States than previously recognized. This review places special emphasis on the recent epidemiologic trends, intra/interspecies transmission and clinical features of each of these zoonoses. In addition, treatment and prevention for each zoonotic pathogen are discussed. Clinicians working in the southern United States should be aware of the presence of those zoonotic infections.

Do helminths cause epilepsy?

Both helminthiases and epilepsy occur globally, and are particularly prevalent in developing regions of the world. Studies have suggested an association between epilepsy and helminth infection, but a causal relationship is not established in many helminths, except perhaps with neurocysticercosis. We review the available literature on the global burden of helminths, and the epidemiological evidence linking helminths to epilepsy. We discuss possible routes that helminths affect the central nervous system (CNS) of humans and the immunological response to helminth infection in the CNS, looking at possible mechanisms of epileptogenesis. Finally, we discuss the current gaps in knowledge about the interaction between helminths and epilepsy.

Toxocariasis/cysticercosis seroprevalence in a long-term rural settlement, São Paulo, Brazil

Seroprevalence of Toxocara and Taenia solium and risk factors for infection with these parasites were explored in a long-term rural settlement in São Paulo state, Brazil. An ELISA for the detection of anti-Toxocara IgG and IgE and anti-T. solium cysticerci was standardized using Toxocara excretory-secretory antigens (TES) obtained from the cultured second-stage larvae of T. canis and by vesicular fluid antigen from Taenia crassiceps cysticerci (VF). For cysticercosis, the reactive ELISA samples were assayed by Western blot using 18 kDa and 14 kDa proteins purified from VF. Out of 182 subjects, 25 (13·7%) presented anti-Toxocara IgG and a positive correlation between total IgE and the reactive index of specific anti-TES IgE (P=0·0265) was found amongst the subjects found seropositive for anti-Toxocara IgG. In these individuals 38·0% showed ocular manifestations. The frequency of anti-T. solium cysticerci confirmed by Western blot was 0·6%. Seropositivity for Toxocara was correlated with low educational levels and the owning of dogs. Embryonated eggs of Toxocara spp. were found in 43·3% of the analysed areas.

Helminthic parasites and seizures

A large number of helminthic parasites are known to involve the central nervous system (CNS) and produce neurologic symptoms including seizures and epilepsy. Taenia solium (the pork tapeworm) is perhaps most widely prevalent and well known for its association with seizures and epilepsy. Many of the other helminthic disorders have fairly restricted geographic predilections and their occurrence in much of the remaining world is limited to rare cases among travelers and immigrants. Nonetheless, knowledge about the helminthic disorders, the life cycle of their causative agents, and their clinical manifestations and diagnostic features are important in order to recognize them.

Neurotoxocarosis

Infection of humans with embryonated eggs of Toxocara canis (larva migrans) remains asymptomatic, or results in covert or common toxocarosis, visceral larva migrans syndrome, or ophthalmologic and neurologic impairment. Though neurological manifestations of Toxocara canis larvae are rare, toxocarosis remains an important differential diagnosis of various neurological disorders. Manifestations of the central nervous system are dementia, meningo-encephalitis, myelitis, cerebral vasculitis, epilepsy, or optic neuritis. Manifestations of the peripheral nervous system comprise radiculitis, affection of cranial nerves, or musculo-skeletal involvement. If toxocarosis is neglected, ignored, or refused as a differential of these abnormalities, it may be easily overlooked for years. Early recognition and treatment of the infection is, however, of paramount importance since it reduces morbidity and mortality and the risk of secondary superinfection. Like the visceral manifestations, neurological manifestations of toxocarosis are treated by benzimidazole components, most frequently albendazole, corticosteroids, or diethylcarbamazine. If detected and treated early, the prognosis of neurological manifestations of toxocarosis is favourable.

The global burden and stigma of epilepsy

Epilepsy is one of the most prevalent neurological conditions and it knows no age, racial, social class, geographic, or national boundaries. The impact of epilepsy rests not only on the individual patient, but also on the family and indirectly on the community. The burden of epilepsy may be due to the physical hazards of epilepsy resulting from the unpredictability of seizures; the social exclusion as a result of negative attitudes of others toward people with epilepsy; and the stigma, as children with epilepsy may be banned from school, adults may be barred from marriage, and employment is often denied, even when seizures would not render the work unsuitable or unsafe. Furthermore, epilepsy is a disorder associated with significant psychological consequences, with increased levels of anxiety, depression, and poor self-esteem compared with people without this condition. Here we discuss some of the aspects of the global burden of epilepsy.

Epilepsy and toxocariasis: a case-control study in Italy

PURPOSE

To assess the relationship between epilepsy and toxocariasis in adult subjects by means of a case-control study in Catania, Italy.

METHODS

People with epilepsy (PWE) were randomly selected from the database of the center of epilepsy of our department. Epilepsy was diagnosed according to the definition proposed by the International League Against Epilepsy. One healthy control per each case was selected among subjects who went to the central laboratory for a hematological check. Control subjects underwent a complete neurological examination to exclude the presence of neurological disorders. PWE and controls were assessed serologically for antibodies against Toxocara canis (T. canis) by an immunoblotting assay.

RESULTS

Two hundred thirty-one PWE (110 men and 121 women) and 201 controls (126 men and 75 women) were enrolled in the study. Of the 231 PWE, 152 presented partial seizures. Antibodies anti-T. canis were found in 38 PWE (16.4%) and in 13 controls (6.6%) giving a crude OR of 2.85 (95% CI 1.47-5.51). Adjusted OR estimated by logistic regression was 3.90 (95% CI 1.91-7.98). This association was mainly due to a significant association between Toxocara antibodies and partial epilepsy (adjusted OR 4.69; 95% CI 2.24-9.80), while a positive, but not significant, association was found with generalized seizures (adjusted OR 1.74; 95% CI 0.60-5.05).

CONCLUSION

We found a significant association between T. canis seropositivity and epilepsy and a stronger association was found with partial epilepsy. Our finding suggests that toxocariasis may increase the risk of epilepsy.

Epilepsy and toxocariasis: a case-control study in Burundi

PURPOSE

A case-control study to assess the relationship between epilepsy and toxocariasis was carried out in the Kiremba population, Burundi.

METHODS

People with epilepsy (PWE) were diagnosed according to the definition proposed by the International League Against Epilepsy (ILAE). Seizures were classified according to the classification proposed by ILAE in 1981. One control per case was selected matched by age (+/-5 years). Control subjects also lived in Kiremba, had neither neurological disorders nor kinship with the PWE. Cases and controls were assessed serologically for antibodies against Toxocara canis by an immunoblotting assay. Odds ratios (ORs) and 95% CI were determined using conditional regression analysis for matched case-control study.

RESULTS

One hundred ninety-one PWE (99 men and 92 women) and 191 age-matched controls (72 men and 112 women) were enrolled in the study. Of the 191 PWE, 113 presented partial seizures while 73 generalized seizures and five were unclassifiable. Antibodies anti T. canis were found in 114 PWE (59.7%) and in 97 controls (50.8%). Multivariate analysis (conditional logistic regression) showed a significant association between positivity for T canis and epilepsy with an adjusted OR of 2.13 (95% CI 1.18-3.83; p-value 0.01).

CONCLUSIONS

We found a significant association between toxocariasis and epilepsy. In agreement with a previous study, our finding suggests that toxocariasis may increase the risk of developing epilepsy in endemic areas and could participate to the high burden of epilepsy in tropical areas.

Combined use of an antigen and antibody detection enzyme-linked immunosorbent assay for cysticercosis as tools in an epidemiological study of epilepsy in Burundi

OBJECTIVE

To evaluate the benefits of the detection of both circulating antibodies (Ab) and antigens (Ag) for the diagnosis of cysticercosis in people with epilepsy. Neurocysticercosis is a cause of neurological diseases world-wide, especially epilepsy. The clinical symptoms of neurocysticercosis are non-specific and diagnosis is often difficult.

METHODS

Serum samples were collected from subjects in a matched case-control study for epilepsy in the Kiremba area, Burundi, between March and April 2001 (epileptic cases=303; controls without epilepsy=606). The enzyme-linked immunosorbent assay (ELISA) was used for the detection of antibodies (Ab-ELISA) and circulating Ag (Ag-ELISA).

RESULTS

The Ab-ELISA revealed 58.7% positivity in epilepsy cases and 31.4% in healthy controls; and Ag-ELISA revealed 38.3% positivity in epilepsy cases and 20.0% in controls. The matched odds ratios were 3.6 (95% CI: 2.5-4.9) for Ab-ELISA, and 2.9 (95% CI: 2.1-4.3) for Ag-ELISA.

CONCLUSION

Both Ag- and Ab-ELISA detected a significantly higher number of seropositives among people with epilepsy than among controls. The risk of epilepsy was high in cases with a positive Ag-ELISA, although less important than in cases with positivity for Ab-ELISA. Dead or degenerating cysticerci appear to be more frequently associated with epilepsy than living cysts. The high number of people with circulating Ag of Taenia solium suggests that the study area is a focus of active transmission of the parasite.

Evaluation of immunodiagnostics for toxocarosis in experimental porcine cysticercosis

We assessed whether immunodiagnostic tests for cysticercosis can cross-react with the currently available immunodiagnostic tests for Toxocara canis in an established animal model for cysticercosis infection in pigs, known host for Toxocara. We examined by TES-enzyme-linked immunosorbent test and immunoblot assay for toxocarosis and cysticercosis the baseline and final follow-up sera of 10 pigs, before and after (3 months) infection with Taenia solium. After successful cysticercosis infection, the nine evaluable pigs became seropositive to T. solium (enzyme-linked immunoelectrotransfer blot assay), but did remain seronegative for Toxocara in both assays, documenting the lack of cross-reactivity with anti-T. solium antibodies in both T. canis assays. These findings should help clinicians better interpret serology for toxocariosis and cysticercosis in endemic areas for both helminth infections.

Epilepsy and seropositivity rates of Toxocara canis and Toxoplasma gondii

PURPOSE

Increased seropositivity for Toxoplasma gondii and Toxocara canis have been observed in epileptic patients. Our aim is to determine whether there is any relationship between these agents and epilepsy in our cryptogenic epilepsy group.

MATERIAL AND METHODS

We studied specific IgG antibodies against T. gondii and T. canis in 100 cryptogenic epileptic patients and 50 healthy volunteers that had no history of epilepsy in their first degree relatives. We studied T. gondii and T. canis-specific IgG antibody serum levels and compared the values of these two groups.

RESULT

We found similar T. gondii and T. canis serum IgG antibodies in patients with cryptogenic epilepsy and in the control group, even though the control group included more animal owners.

CONCLUSION

We did not show any relationships between epilepsy and positive T. gondii and T. canis serology in our epileptic patients.

Prevalence and Clinical Features of Epilepsy in Argentina

OBJECTIVE

To ascertain the prevalence of epilepsy in Junín, a town of 70,000-80,000 inhabitants from the Province of Buenos Aires, Argentina.

BACKGROUND

Some South American communities have reported extremely high prevalences of epilepsy. We investigated whether Junín would also have a high prevalence.

DESIGN/METHODS

Systematic sampling was used to select 5,839 households (sampling fraction = 25%). Participating households amounted to 5,648 (97%), with 17,049 persons. A two-phase case-finding strategy was used. Phase 1 was the screening of the 17,049 persons, which was performed by trained but medically unsophisticated interviewers. Phase 2 was the neurological evaluation of the 250 persons who were screened positive for epilepsy. Diagnoses were based on defined diagnostic criteria.

RESULTS

As of January 1, 1991 (prevalence day), 106 persons had epilepsy, including 64 (60%) with active epilepsy. Among these, 9 (14%) were epilepsy cases newly diagnosed by survey neurologists, and 50 (78%) were on antiepileptic treatment at the time of the survey. Regarding the same 64 persons, seizures were generalized in 37 (58%) and partial in 24 (38%). Lifetime prevalence of epilepsy was 6.2/1,000 (6.3/1,000, age adjusted to the world standard population). Total point prevalence for active epilepsy was 3.8/1,000 (4.0 for females and 3.5 for males). In addition, prevalence peaked at the ages of 40-59 for females and 0-4 for males.

CONCLUSIONS

This is one of the first community-based studies of epilepsy in Argentina, and the prevalence results provide new epidemiological data contributing to our understanding of the different prevalence rates found in Latin America.

Prevalence of Epilepsy in a Rural District of Central Lao PDR

PURPOSE

To assess the prevalence of epilepsy in a rural district of Lao PDR and to describe the clinical and epidemiological profile of the disease.

METHODS

Door-to-door screening was performed on the entire population of 8 randomly selected villages in the Hinheub district, using an internationally validated and standardized questionnaire. Additional passive case detection was performed through village key informants. Suspected epilepsy patients identified by the questionnaire were revisited and examined by an experienced neurologist on two follow-up visits. The confirmation of epilepsy was based only on an in-depth clinical examination. Electroencephalograms were performed at the district health care center.

RESULTS

In the 8 villages, 277 suspected cases of epilepsy were identified among 4,310 interviewed subjects; 194 of whom (70%) underwent a clinical examination by a neurologist during the first visit while 65 of 83 remaining suspected cases were seen on the second confirmation visit. Twenty-seven persons with epilepsy were identified. Six additional patients were diagnosed in 219 self-referred subjects. An overall prevalence of 7.7 cases of epilepsy per thousand inhabitants was calculated (95% CI 5.3-10.7). Generalized epilepsy (21 cases, 63.6%) was commoner than partial epilepsy (9 cases, 27.3%). The remaining 3 cases (9.1%) were not-classifiable as either generalized or partial. EEG abnormal findings were found in 12 of the 24 patients (50.0%) who had an EEG registration.

CONCLUSIONS

This is the first study in Lao PDR to estimate the prevalence of epilepsy. Compared to Western countries it shows a pattern towards a higher prevalence.

Epidemiologic classification of seizures associated with neurocysticercosis: observations from a sample of seizure disorders in neurologic care in India

AIMS

To determine the etiologic role of neurocysticercosis (NC) in a hospital-based sample of epilepsies divided according to International League Against Epilepsy (ILAE) epidemiological criteria and number of seizures prior to presentation.

METHODS

A sample comprising 1026 consecutive patients with either definite seizures or epilepsy attending a Neurology Outpatient Service was divided into four subgroups: single seizure (n = 314), incident epilepsy (n = 127), prevalent epilepsy (n = 398) and recurrent acute symptomatic seizures (RASS) (n = 175). The etiologic contribution of NC to each of the subgroups was examined with imaging studies.

RESULTS

Neurocysticercosis was diagnosed on imaging studies in 34.6% of patients with seizure disorder of any type, 59.2% of those with a single seizure, 23.7% of those with recurrent seizure disorder, 92.0% of those with RASS, none of cases of incident epilepsy and 2.0% with prevalent epilepsy. A diagnosis of NC was significantly associated with single seizures (P < 0.001).

CONCLUSIONS

Imaging abnormalities consistent with NC are frequently noted in persons presenting with a single seizure in neurologic care in NC-endemic countries like India. The probability of diagnosing NC diminishes with increasing numbers of seizures. Among samples of individuals with recurrent-unprovoked seizures, it is rare for imaging to demonstrate lesions of NC.

Adult epilepsy

The epilepsies are one of the most common serious brain disorders, can occur at all ages, and have many possible presentations and causes. Although incidence in childhood has fallen over the past three decades in developed countries, this reduction is matched by an increase in elderly people. Monogenic Mendelian epilepsies are rare. A clinical syndrome often has multiple possible genetic causes, and conversely, different mutations in one gene can lead to various epileptic syndromes. Most common epilepsies, however, are probably complex traits with environmental effects acting on inherited susceptibility, mediated by common variation in particular genes. Diagnosis of epilepsy remains clinical, and neurophysiological investigations assist with diagnosis of the syndrome. Brain imaging is making great progress in identifying the structural and functional causes and consequences of the epilepsies. Current antiepileptic drugs suppress seizures without influencing the underlying tendency to generate seizures, and are effective in 60-70% of individuals. Pharmacogenetic studies hold the promise of being able to better individualise treatment for each patient, with maximum possibility of benefit and minimum risk of adverse effects. For people with refractory focal epilepsy, neurosurgical resection offers the possibility of a life-changing cure. Potential new treatments include precise prediction of seizures and focal therapy with drug delivery, neural stimulation, and biological grafts.

Sero-epidemiology of Toxocara canis infection among aboriginal schoolchildren in the mountainous areas of north-eastern Taiwan

A sero-epidemiological study of Toxocara canis infection was conducted among Atayal schoolchildren (aged 7-12 years) residing in the mountainous areas of north-eastern Taiwan. The 73 children investigated were each checked for anti-Toxocara IgG, in ELISA based on the larval excretory-secretory antigens of T. canis larvae. A short, self-administered questionnaire was then used to collect relevant information from each subject, including data on the keeping of dogs, playing in soil, eating raw vegetables, and whether the subjects normally washed their hands before eating. Once the seropositive children had been identified, odds ratios (OR), with their corresponding 95% confidence intervals (CI) and P-values, were calculated for each potential risk factor. When diluted 1:64, sera from 42 (57.5%) of the children gave a positive result in the ELISA, indicating that these 42 children were seropositive for T. canis infection. Seropositivity did not appear to be associated with the age or gender of the subject, the eating of raw vegetables, or the regular failure to wash hands prior to a meal. Compared with the other subjects, however, those who admitted living in a household where dogs were kept (OR = 3.79; CI = 1.23-11.69; P = 0.02) or playing in soil (OR = 3.00; CI = 1.10-8.16; P = 0.03) appeared at increased risk of seropositivity.

Epilepsy and neurocysticercosis in rural Bolivia: a population-based survey

PURPOSE

To evaluate the frequency of neurocysticercosis (NCC) in a well-defined prevalent cohort of epilepsy patients in the rural area of the Cordillera province.

METHODS

We carried out a two-phase door-to-door neuroepidemiologic survey in a sample of 10,124 subjects in a rural area of the Cordillera Province, Bolivia, to detect the prevalence of the most common neurologic disorders including epilepsy. A team of health workers administered a standard screening instrument for neurologic diseases; subjects found positive at the screening phase underwent a complete neurologic examination. Epilepsy patients were diagnosed according to the definition proposed by the International League Against Epilepsy (ILAE, 1993). Epilepsy patients identified this way underwent electroencephalographic recording, computed tomography (CT) scan, and serologic evaluation to detect antibodies against Taenia solium by enzyme-linked immunoelectrotransfer blot.

RESULTS

At the end of the survey, we detected 124 defined prevalent epilepsy patients. On the basis of the classification proposed by the ILAE in 1981, partial seizures were the most common type diagnosed (66 patients, 53.3%). Of the 124 patients, 105 underwent CT scan, and a serum sample was taken to detect antibodies against T. solium in 112 patients; for 97 patients, both neuroradiologic and serologic data were available. Considering radiologic, serologic, and clinical features, of these 124 patients, 34 (27.4%) fulfilled the diagnostic criteria for definitive or probable NCC proposed in 2001. Of these 34 patients 24 (70.6%) had partial seizures.

CONCLUSIONS

Our data confirm a high frequency of NCC among a well-defined prevalent cohort of epilepsy patients.