Cysticercosis as a major risk factor for epilepsy in Burundi, east Africa

The epidemiology of human Taenia solium infections: A systematic review of the distribution in Eastern and Southern Africa

Background

Taenia solium is a tapeworm that causes taeniosis in humans and cysticercosis in humans and pigs. Within Eastern and Southern Africa (ESA), information on the presence of human taeniosis and cysticercosis seems scarce. This systematic review aimed to describe the current information available and gaps in the epidemiology of human T. solium infections in ESA.

Methods/Principle findings

Scientific literature published between 1st January 2000 and 20th June 2022 in international databases [MEDLINE (Ovid), Embase (Ovid), Global Health (Ovid), Scopus (Elsevier), African Index Medicus (via WHO Global Index Medicus), and Open Grey] was systematically reviewed for ESA. The study area included 27 countries that make up the ESA region. Information on either taeniosis, cysticercosis or NCC was available for 16 of 27 countries within the region and a total of 113 reports were retained for the review. Most case reports for cysticercosis and NCC were from South Africa, while Tanzania had the most aggregated cysticercosis reports. Eleven countries reported on NCC with seven countries reporting data on NCC and epilepsy. Unconfirmed human T. solium taeniosis cases were reported in nine countries while two countries (Madagascar and Zambia) reported confirmed T. solium cases. The cysticercosis seroprevalence ranged between 0.7–40.8% on antigen (Ag) ELISA and between 13.1–45.3% on antibody (Ab) ELISA. Based on immunoblot tests the Ab seroprevalence was between 1.7–39.3%, while the proportion of NCC-suggestive lesions on brain CT scans was between 1.0–76% depending on the study population. The human taeniosis prevalence based on microscopy ranged between 0.1–14.7%. Based on Copro Ag-ELISA studies conducted in Kenya, Rwanda, Tanzania, and Zambia, the highest prevalence of 19.7% was reported in Kenya.

Conclusions

Despite the public health and economic impact of T. solium in ESA, there are still large gaps in knowledge about the occurrence of the parasite, and the resulting One Health disease complex, and monitoring of T. solium taeniosis and cysticercosis is mostly not in place.

Status of epilepsy in the tropics: An overlooked perspective

Epilepsy is one of the most common serious chronic neurological diseases affecting people of all ages globally. It is characterized by recurrent seizures. About 50 million people worldwide have epilepsy. Indubitably, people with epilepsy (PWE) may be without access to appropriate treatment. Many studies have examined the molecular mechanisms and clinical aspects of epilepsy; nonetheless, the treatment gap exists in some special areas. In the tropics, the specific geographical and ecological conditions and a lack of medical resources result in neglect or delay of diagnosis for PWE. Herein, we summarized the epidemiology of epilepsy in the tropics and discussed the disease burden and existing problems, aiming to offer a medical environment for patients in need and highlight the importance of reducing the epileptic disease burden in tropical countries.

Assessing the burden of Taenia solium cysticercosis in Burundi, 2020

Background

Taenia solium cysticercosis is a zoonotic disease that is endemic in many low- and middle-income countries where risk factors for disease transmission are present. The economic impact of cysticercosis on public health and on the pig production sector is not well known in many of those countries, including Burundi. This study aimed at estimating the burden of T. solium cysticercosis in Burundi including data on humans and pigs.

Methods

Epidemiological and economic data were collected from literature up to July 30, 2021 and governmental and non-governmental agencies. Direct and indirect costs for neurocysticercosis (NCC)-associated epilepsy and losses due to porcine cysticercosis were estimated to assess the economic burden, while the health burden was estimated using zoonotic disability-adjusted life years (zDALYs). Different probability distributions (Uniform, Beta, Dirichlet and Gamma) were applied depending on the type of epidemiological parameter. Monte Carlo simulations and 100,000 iterations were used to calculate the 95% uncertainty interval (UI) for each parameter and perform sensitivity analyses.

Results

In Burundi, 4.26 million USD (95% UI, 1,858,308–8,190,951) were estimated as economic impact due to T. solium cysticercosis in humans and pigs, of which 40.2% (95% UI, 10.3–75.1) of the total costs were due to NCC-associated epilepsy and 59.8% (95% UI, 24.9–89.7) of the losses due to porcine cysticercosis. The cost per NCC-associated epilepsy case was 72 USD (95% UI, 25–168), representing 30.8% of the GDP per capita in 2020. The probable incident cases and deaths for NCC-associated epilepsy were 9065 (95% UI, 2370–16,716) and 61 (95% UI, 16–114), respectively. More than 2 zDALYs (95% UI, 1.1–3.4) per thousand person-years was estimated, of which an average of 1.3 DALYs [0;0] (95% UI, 0.3–2.6) was due to NCC- associated epilepsy and 0.8 animal loss equivalents (ALEs) (95% UI, 0.3–1.5) due to porcine cysticercosis.

Conclusions

This study provides evidence of a significant burden of T. solium cysticercosis for Burundi’s population. We urge policy makers to use these evidence-based results and put T. solium cysticercosis on the public health agenda of the country. This study recommends urgent action to find solutions for integrated control strategies for T. solium cysticercosis in Burundi.

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.

Evidence for Transmission of Taenia solium Taeniasis/Cysticercosis in a Rural Area of Northern Rwanda

Cysticercosis is a parasitic infection caused by the metacestode larval stage (cysticercus) of Taenia solium. In humans, cysticercosis may infect the central nervous system and cause neurocysticercosis, which is responsible for over 50,000 deaths per year worldwide and is the major cause of preventable epilepsy cases, especially in low-income countries. Cysticercosis infection is endemic in many less developed countries where poor hygiene conditions and free-range pig management favor their transmission. A cross-sectional study was conducted in 680 children from a rural primary school in Gakenke district (Northern province of Rwanda). Stool samples were collected from participants and analyzed using the Kato-Katz method (KK), formol-ether concentration (FEC), and/or copro-antigen enzyme-linked immunosorbent assay (CoAg-ELISA) to detect taeniasis. Blood samples were collected and analyzed using enzyme-linked immunoelectrotransfer blot (EITB) and antigen enzyme-linked immunosorbent assay (Ag-ELISA) to detect human cysticercosis. The overall proportion of taeniasis positivity was 0.3% (2/680), and both cases were also confirmed by CoAg-ELISA. A total of 13.3% (76/572) of the children studied were positive to cysticercosis (T. solium-specific serum antibodies detected by EITB), of whom 38.0% (27/71) had viable cysticercus (T. solium antigens by Ag-ELISA). This study provides evidence of the highest cysticercosis prevalence reported in Rwanda in children to date. Systematic investigations into porcine and human cysticercosis as well as health education and hygiene measures for T. solium control are needed in Gakenke district.

Prevalence and risk assessment of porcine cysticercosis in Ngozi province, Burundi

Cysticercosis is a major zoonotic disease in many developing countries leading to substantial economic and public health impacts on affected communities. Due to a lack of updated data on T. solium cysticercosis in Burundi, the present study was carried out to determine the prevalence of porcine cysticercosis and to identify potential associated risk factors in Ngozi province. This study was conducted in Ngozi and Marangara communes of Ngozi province during January and February 2020. A multistage random sampling strategy was used. Tongue palpation was performed on pigs to diagnose cysticercosis. Randomly selected heads of pig keeping households were interviewed to assess the risk factors for porcine cysticercosis. A logistic regression model was used to analyse the main risk factors associated with porcine cysticercosis. In total, 496 pigs from 321 households distributed in 16 hills, randomly selected in Ngozi and Marangara communes were inspected. The apparent prevalence by tongue palpation in Ngozi province was 15.5% (95% CI: 12.3-18.7%). In Ngozi and in Marangara communes, the prevalence was 22.9% (95% CI: 17.7-28.2%) and 8.1% (95% CI: 4.6-11.4%), respectively. The true prevalence was estimated at 31% for the province, with a prevalence of 45.8% in Ngozi and 16.2% in Marangara commune, respectively. Pig farming systems including free ranging, tethering and penned part of the day (OR = 3.5; 95% CI: 2.1-6.1; p ≤  0.001) and lack of meat inspection at home slaughter (OR = 2.5; 95% CI: 1.1-5.6; p = 0.019) were significant risk factors associated with porcine cysticercosis. The present findings show that porcine cysticercosis is highly endemic in Ngozi province and that pig management systems currently used in the area permit pigs to have access to human stool. Moreover, lack of meat inspection during home slaughter potentially gives the possibility for household and community members to eat infected pork. Total confinement of pigs, improved hygiene and sanitation in households, and improvement of meat inspection through awareness campaigns and overall health education of the community should be implemented to control T. solium infections.

Epilepsy due to Neurocysticercosis: Analysis of a Hospital Cohort

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

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.

Neurocysticercosis in people with epilepsy in Sub-Saharan Africa: A systematic review and meta-analysis of the prevalence and strength of association

PURPOSE

We analyzed studies on neurocysticercosis (NCC) and epilepsy across Sub-Saharan Africa (SSA) to determine the prevalence of NCC in people with epilepsy (PWE) and the strength of association of NCC with epilepsy in the region.

METHODS

We conducted a systematic review of the existing literature on NCC and epilepsy in SSA. Diagnostic methods for NCC in the studies selected for our analysis included one or more of the following: positive brain CT, serum ELISA and serum EITB. A common prevalence and overall odds-ratio were then estimated using meta-analysis.

RESULTS

A total of 25 (overall) and 20 (case-control) studies met the inclusion criteria for the prevalence and strength of association estimation, respectively. The overall prevalence estimate of NCC in PWE was 22 % [95 % confidence interval [CI]: 17-27.0 %). The figures were higher in the Southern and Eastern Africa sub-region (45 % and 25 % respectively) but lower in the Central and Western Africa sub-region (6 % and 15 % respectively). The prevalence of NCC estimate in PWE varied with method of diagnosis; with 29 % 18 % and 15 % in studies that used a minimum of Brain CT, ELISA and EITB respectively. The overall odds ratio was 2.4 (95 % CI 2.1-2.8), p < 0.0001.

CONCLUSION

The overall prevalence of NCC in PWE in SSA was 22 %. The prevalence figure varied with the sub-region of SSA. The odd of NCC in PWE in SSA was 2.4. In spite of the sub-regional variation in NCC prevalence, this meta-analysis suggests that neurocysticercosis contributes significantly to epilepsy in SSA.

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.

Parasites and epilepsy: Understanding the determinants of epileptogenesis

There is a large body of evidence suggesting that parasites could be a major preventable risk factor for epilepsy in low- and middle-income countries. We review potentially important substrates for epileptogenesis in parasitic diseases. Taenia solium is the most widely known parasite associated with epilepsy, and the risk seems determined mainly by the extent of cortical involvement and the evolution of the primary cortical lesion to gliosis or to a calcified granuloma. For most parasites, however, epileptogenesis is more complex, and other favorable host genetic factors and parasite-specific characteristics may be critical. In situations where cortical involvement by the parasite is either absent or minimal, parasite-induced epileptogenesis through an autoimmune process seems plausible. Further research to identify important markers of epileptogenesis in parasitic diseases will have huge implications for the development of trials to halt or delay onset of epilepsy.

Estimating the association between being seropositive for cysticercosis and the prevalence of epilepsy and severe chronic headaches in 60 villages of rural Burkina Faso

Background

Individuals diagnosed with neurocysticercosis often present with epilepsy and sometimes with progressively worsening severe chronic headaches (WSCH). While cross-sectional associations between seropositivity to cysticercal antigens and epilepsy have been reported, few large scale studies have been conducted in West Africa and none have measured the association between seropositivity to cysticercal antigens and headaches. This study aimed at filling these knowledge gaps by estimating the strength of the cross-sectional association between seropositivity to cysticercal antigens and the prevalence of epilepsy and WSCH in 60 villages of Burkina Faso, West Africa.

Methodology/Principal findings

Baseline data from a cluster randomized controlled trial collected from January 2011 to February 2012 in 60 villages across three provinces in Burkina Faso were used. Between 78 and 80 individuals were screened for epilepsy and WSCH in each village, and those screened positive were confirmed by a physician. Seventy-five percent of all participants were asked to provide a blood sample to test for Taenia solium cysticercus circulating antigens. Hierarchical multivariable logistic models were used to measure the association between seropositivity to cysticercal antigens and epilepsy (lifetime and active) as well as WSCH. Among 3696 individuals who provided a blood sample, 145 were found to have epilepsy only, 140 WSCH only and 19 both. There were positive associations between seropositivity to cysticercal antigens and active epilepsy (prevalence odds ratio (POR): 2.40 (95%CI: 1.15–5.00)) and WSCH (POR: 2.59 (1.34–4.99)).

Conclusions/Significance

Our study is the first to demonstrate a cross-sectional association between seropositivity to cysticercal antigens and WSCH in a large community-based study conducted in West Africa. The measured cross-sectional association had a strength similar to the ones previously observed between seropositivity to cysticercal antigens and lifetime or active epilepsy. As a result, preventing new cysticercosis cases in communities may reduce the prevalence of these two important neurological disorders.

Taenia solium is a parasite that can be transmitted between humans and pigs in areas with poor sanitation and pig management practices. When this parasite infects the human brain, it can cause epilepsy or severe headaches. Our study aimed to measure the association between being seropositive to cysticercal antigens and having epilepsy (lifetime and active) or severe headaches in 60 villages of Burkina Faso. We found that active epilepsy and severe headaches were associated with seropositivity to cysticercal antigens. These results confirm prior studies which suggested an association between being seropositive for cysticercal antigens and these two neurological symptoms. Preventing cysticercosis could reduce new cases of these two neurological symptoms from occurring.

The status and health burden of neurocysticercosis in Mbulu district, northern Tanzania

OBJECTIVE

The objective of this study was to assess the extent and health burden of neurocysticercosis in the general community of the Mbulu district, northern Tanzania. About 1051 randomly select participants were screened for human cysticercosis. The Cysticercus Western Blot IgG and Computed Tomography scan were used to detect infection by cysticerci. The DALYs was used to assess the community's health burden vis-a-vis neurocysticercosis.

RESULTS

The sero-prevalence of HCC was 16.27%. About 76% of 25 selected human cysticercosis sero-positives had neurocysticercosis suggestive lesions on CT scan and 74% had history of epilepsy. Epilepsy caused 2.8 years of life lost and 2.2 healthy years of life lost due to disability per 1000 person-years in Mbulu. The average DALYs imposed due to neurocysticercosis and epilepsy were 3.0 and 3.9 per 1000 person-years, respectively. Neurocysticercosis is a serious public health concern in northern Tanzania.

Etiologies of non-genetic epilepsies of child and adolescent, newly diagnosed in Ouagadougou, Burkina Faso

Introduction

in sub-Saharan Africa, epilepsy is common and mainly concerns children before the age of 15 years. The data on childhood epilepsy is parcel, but a high prevalence of non-genetic epilepsy is frequently reported. EEG, TDM and MRI devices are rare. The aim of this work was to study the etiological aspects of non - genetic epilepsy of the child and adolescent, newly diagnosed in Ouagadougou, Burkina Faso.

Methods

This was a cross-sectional, descriptive, multicentric study, from 01/01/2016 to 31/12/2016, involving patients aged 0 to 18 years old, epileptic, newly diagnosed, in the city of Ouagadougou. Each patient included in the study was to have had an EEG and brain CT scan and/or brain MRI and to gather the anamnestic and electro clinical arguments for non-genetic epilepsy. Sociodemographic, clinical, EEG and neuroradiological data were analyzed. An univariate analysis was used to determine the electro-clinical and neuro-radiological characteristics associated with epilepsies of structural causes.

Results

In all 115 patients were collected, with an average age of onset of epilepsy of 8.2 years, a male predominance with a sex ratio to 1.67. Risk factors of epilepsy was present in 74.8%; They were dominated by perinatal events in 79.1%. Focal seizures, daily frequency of these seizures and focal epilepsy, were predominant, respectively in 53%, 58% and 60.9% of cases. Brain scan and Brain MRI where performed in 90.4% and 9.6% of patients, respectively. The brain sequelaes of perinatal adverse events, the sequelae of central nervous system infections, and the sequelae of cranial and brain trauma, with 34.8%, 14.8%, and 5.2% respectively, were the main causes of non- genetic epilepsies of the child and adolescent. No cause was identified in 37.4% of cases.

Conclusion

The improvement of policies in the field of maternal and child health and the generalization of the control of infectious and parasitic diseases, including malaria, may contribute to the reduction of non-genetic epilepsy in sub-Saharan Africa.

Taenia solium cysticercosis in West Africa: status update

Cysticercosis is caused by the larvae of the cestode Taenia solium. Few data are available on the prevalence of this disease in pigs and humans in West African countries. The aim of this study was to provide an overview of existing data concerning the spread of this parasitosis in the countries of the Economic Community of West African States (ECOWAS) on the basis of the literature published over the last five decades. Systematic searches for publications were carried out on PubMed and Google Scholar, as well as in certain regional and local journals. From a total of 501 articles initially retrieved concerning T. solium cysticercosis in West African countries, only 120 articles were relevant for this review and therefore finally retained. For pigs, only eight out of sixteen countries of the region have reported porcine cysticercosis. Post-mortem examination of carcasses at slaughterhouses, meat inspection at butcheries or tongue inspection in herds have been the main source of data, but may not entirely reflect actual parasite distribution. For humans, only five out of sixteen countries reported epidemiological data on neurocysticercosis. Most data referred to neurocysticercosis prevalence among epileptic patients or isolated clinical cases. Furthermore, existing data are often old. Overall, T. solium cysticercosis remains largely neglected in West Africa, and its prevalence appears not to be affected by any religion in particular. There is an urgent need to promote and implement health partnerships and programs on this disease in order to collect more data and identify sensitive populations in the countries of the ECOWAS area.

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.

Taenia solium taeniosis/cysticercosis and the co-distribution with schistosomiasis in Africa

Background

This study aimed to map the distribution of Taenia solium taeniosis/cysticercosis and the co-distribution with schistosomiasis in Africa. These two major neglected tropical diseases are presumed to be widely distributed in Africa, but currently the level of co-distribution is unclear.

Methods

A literature search on T. solium taeniosis/cysticercosis was performed to compile all known studies on the presence of T. solium and apparent prevalence of taeniosis and porcine cysticercosis in Africa. Studies were geo-referenced using an online gazetteer. A Bayesian framework was used to combine the epidemiological data on the apparent prevalence with external information on test characteristics to estimate informed district-level prevalence of taeniosis and porcine cysticercosis. Districts with T. solium taeniosis/cysticercosis presence were cross-referenced with the Global Neglected Tropical Diseases Database for schistosomiasis presence.

Results

The search strategies identified 141 reports of T. solium in Africa from 1985 to 2014 from a total of 476 districts in 29 countries, 20 with porcine cysticercosis, 22 with human cysticercosis, and 16 with taeniosis, in addition to 2 countries identified from OIE reports. All 31 countries were considered, on national scale, to have co-distribution with schistosomiasis. Presence of both parasites was confirmed in 124 districts in 17 countries. The informed prevalence of taeniosis and porcine cysticercosis were estimated for 14 and 41 districts in 10 and 13 countries, respectively.

Conclusions

With the paucity of data, T. solium infection is grossly under-reported and expected to be more widespread than this study suggests. In areas where co-distribution occurs there is a need for increased emphasis on evaluation of integrated intervention approaches for these two helminth infections and allocation of resources for evaluating the extent of adverse effects caused by mass drug administration.

Electronic supplementary material

The online version of this article (doi:10.1186/s13071-015-0938-7) contains supplementary material, which is available to authorized users.

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.

Prevalence and risk factors for active convulsive epilepsy in rural northeast South Africa

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Epilepsy is prevalent in rural South Africa, but less than other parts of Africa.

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Most epilepsy starts in childhood.

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Poor obstetric history and snoring were associated with active convulsive epilepsy.

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HIV and parasitic infection were not associated with active convulsive epilepsy.

Rationale

Epilepsy is among the most common neurological disorders worldwide. However, there are few large, population-based studies of the prevalence and risk factors for epilepsy in southern Africa.

Methods

From August 2008 to February 2009, as part of a multi-site study, we undertook a three-stage, population-based study, embedded within the Agincourt health and socio-demographic surveillance system, to estimate the prevalence and identify risk factors of active convulsive epilepsy (ACE) in a rural South African population.

Results

The crude prevalence of ACE, after adjusting for non-response and the sensitivity of the screening method, was 7.0/1,000 individuals (95%CI 6.4–7.6) with significant geographic heterogeneity across the study area. Being male (OR = 2.3; 95%CI 1.6–3.2), family history of seizures (OR = 4.0; 95%CI 2.0–8.1), a sibling with seizures (OR = 7.0; 95%CI 1.6–31.7), problems after delivery (OR = 5.9; 95%CI 1.2–24.6), and history of snoring (OR = 6.5; 95%CI 4.5–9.5) were significantly associated with ACE. For children, their mother's exposure to some formal schooling was protective (OR = 0.30; 95%CI 0.11–0.84) after controlling for age and sex. Human immunodeficiency virus was not found to be associated with ACE.

Conclusions

ACE is less frequent in this part of rural South Africa than other parts of sub-Saharan Africa. Improving obstetric services could prevent epilepsy. The relationship between snoring and ACE requires further investigation, as does the relative contribution of genetic and environmental factors to examine the increased risk in those with a family history of epilepsy.

Epilepsy prevalence, potential causes and social beliefs in Ebonyi State and Benue State, Nigeria

Epilepsy is a common neurological disorder in Nigeria. Many individuals are affected in rural areas, although prevalence data is not available. In this study we aimed to establish the prevalence of epilepsy in a rural community in south-east Nigeria, a community suspected for having a high number of people living with epilepsy. We compared this with the prevalence in a nearby semi-urban community in north-central Nigeria. In both communities we identified potential causes of epilepsy and obtained information on the social beliefs regarding epilepsy. We used door-to-door surveys and focus group discussions. The epilepsy prevalence in the rural community was 20.8/1000 [95% confidence interval (CI): 15.7-27.4]. The prevalence in the semi-rural community was lower, namely 4.7/1000 [CI: 3.2-6.9]. The difference in prevalence was highly significant (χ(2)-test, p<0.0001). In both communities most people with epilepsy were in the age range of 7-24 years. Causes that might be contributory to the prevalence of epilepsy in both communities included poor obstetric practices, frequent febrile convulsions, head trauma, meningitis and neurocysticercosis. In both communities we found stigma of people with epilepsy. In conclusion, the epilepsy prevalence in the semi-urban community is similar to that in industrialized countries. In contrast, the rural community has a much higher prevalence. This may require the establishment of specific community-based epilepsy control programs. Community interventions should focus on treatment of acute epilepsy and on stigma reduction.

High prevalence of cysticercosis in people with epilepsy in southern Rwanda

Background

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

Methodology/Principal findings

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

Conclusions/Significance

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

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

Understanding of and attitudes towards people with epilepsy among community-based rehabilitation volunteers in Guinea-Bissau

BACKGROUND

Community-based epilepsy care programs improve access to epilepsy treatment in resource-poor settings. Community volunteers are important to these services. Most studies on familiarity with, understanding of, and attitudes towards people with epilepsy (PWE), however, ignore these volunteers.

METHODS

We explored these issues among 15 community volunteers involved in a community-based rehabilitation child epilepsy service recently initiated in Guinea-Bissau using face-to-face interviews.

RESULTS

We found that the volunteers had a reasonable understanding of epilepsy, moderate attitudes towards PWE, and a good understanding of difficulties PWE encounter in society.

CONCLUSION

Evaluation of understanding and attitudes of community volunteers may be useful to improve low-cost community-based epilepsy programs. A correct understanding of epilepsy among community volunteers may increase effective treatment of and support to children with epilepsy through community-based epilepsy programs.

Case-control studies on the relationship between onchocerciasis and epilepsy: systematic review and meta-analysis

OBJECTIVE

A systematic review and meta-analysis of all available case-control studies on the relationship between onchocerciasis and epilepsy. Because age and level of onchocerciasis endemicity in the area of residence are major determinants for infection, an additional analysis was performed, restricted to studies achieving control of these confounding factors.

DATA SOURCES

Medical databases, the "African Neurology Database, Institute of Neuroepidemiology and Tropical Neurology, Limoges," reference lists of relevant articles, commercial search engines, up to May 2012.

METHODS

We searched for studies examining infection status with Onchocerca volvulus in persons with epilepsy (PWE) and without epilepsy (PWOE) providing data suitable for the calculation of pooled odds ratios (ORp) and/or standardized mean differences (SMD) using random-effects models.

RESULTS

Eleven studies providing data of qualitative skin biopsies for diagnosis of onchocerciasis were identified. Combined analysis on the total sample of 876 PWE and 4712 PWOE resulted in an ORp of 2.49 (95% confidence interval (95%CI): 1.61-3.86, p<0.001). When this analysis was restricted to those studies achieving control for age, residence and sex (367 PWE, 624 PWOE), an ORp of 1.29 (95% CI: 0.93-1.79; p = 0.139) was found. Presence of nodules for diagnosis of onchocerciasis was analyzed in four studies (225 PWE, 189 PWOE; ORp 1.74; 95%CI: 0.94-3.20; p<0.076), including two studies of the restricted analysis (106 PWE, 106 PWOE; ORp 2.81; 95%CI: 1.57-5.00; p<0.001). One study examined quantitative microfilariae counts in patients without preceding microfilaricidal treatment and demonstrated significantly higher counts in PWE than in PWOE.

INTERPRETATION

Our results strengthen the hypothesis that, in onchocerciasis foci, epilepsy and infection with O. volvulus are associated. Analysis of indicators giving information on infection intensity, namely nodule palpation and quantitative microfilaria count in untreated patients, support the hypothesis that intensity of infection with O. volvulus is involved in the etiology of epilepsy.

Prevalence and risk factors associated with human Taenia solium infections in Mbozi District, Mbeya Region, Tanzania

Background

Taenia solium cysticercosis/taeniosis is emerging as a serious public health and economic problem in many developing countries. This study was conducted to determine prevalence and risk factors of human T. solium infections in Mbeya Region, Tanzania.

Methods and Findings

A cross-sectional survey was conducted in 13 villages of Mbozi district in 2009. Sera of 830 people (mean 37.9±11.3 years (SD); 43% females) were tested for circulating cysticerci antigen (Ag-ELISA) and antibody (Ab-ELISA). A subset of persons found seropositive by Ag-ELISA underwent computed tomography (CT) scan of the brain for evidence of neurocysticercosis. Stool samples from 820 of the same participants were tested for taeniosis by copro-antigens (copro-Ag-ELISA) and formol-ether concentration technique. Cases of T. solium taeniosis were confirmed serologically by EITB assay (rES38). A questionnaire was used for identification of risk factors. Active cysticercosis by positive Ag-ELISA was found in 139 (16.7%) persons while anti-cysticercal antibodies were detected in 376 (45.3%) persons by Ab-ELISA. Among 55 persons positive for Ag-ELISA undergoing CT scan, 30 (54.6%) were found to have structures in the brain suggestive of neurocysticercosis. Using faecal analysis, 43 (5.2%) stool samples tested positive for taeniosis by copro-Ag-ELISA while Taenia eggs were detected in 9 (1.1%) stool samples by routine coprology. Antibodies specifically against adult T. solium were detected in 34 copro-Ag-ELISA positive participants by EITB (rES38) indicating T. solium taeniosis prevalence of 4.1%. Increasing age and hand washing by dipping in contrast to using running water, were found associated with Ag-ELISA seropositivity by logistic regression. Gender (higher risk in females) and water source were risk factors associated with Ab-ELISA seropositivity. Reported symptoms of chronic severe headaches and history of epileptic seizures were found associated with positive Ag-ELISA (p≤0.05).

Conclusion

The present study indicates T. solium infection in humans is highly endemic in the southern highlands of Tanzania.

Cysticercosis caused by the zoonotic pork tapeworm, Taenia solium, is emerging as a serious public health and agricultural problem in sub-Saharan Africa. Surveys have shown cysticercosis in pigs to be highly prevalent in multiple foci in Tanzania, and a hospital-based study in the northern highlands indicated neurocysticercosis as an important cause of epileptic seizures in humans. We present here a cross-sectional community-based survey on the prevalence and risk factors of human cysticercosis and taeniosis conducted in the southern highlands – the major pig-producing area of the country. The most striking findings were that more than 15% of people surveyed were found to have active cysticercosis and nearly half of them were found to have been exposed to larval T. solium indicating a high level of environmental contamination with T. solium eggs. This was supported by finding over 4% of people having had T. solium tapeworms. A subset of persons found positive serologically for active cysticercosis underwent brain scanning and more than half of them were found to have neurocysticercosis. This strong evidence that T. solium cysticercosis/neurocysticercosis/taeniosis is highly endemic in the southern highlands of Tanzania demands urgent attention of regional and national authorities to combat the parasite.

Epilepsy and cysticercosis in Northwest Cameroon: a serological study

PURPOSE

The prevalence of epilepsy in Cameroon is higher than that of the industrialized world and other developing countries. Neurocysticercosis due to Taenia solium infestation has been reported as a major cause of epilepsy in some parts of Cameroon although there are some conflicting data. The prevalence of epilepsy is especially high in the Momo division of the North-West Province of Cameroon. We hypothesized that individuals with epilepsy in this region have a higher percentage of seropositivity to T. solium than matched controls.

METHODS

We conducted a case-control study in the Momo subdivision of Ngie. Individuals with epilepsy were recruited from the health centers in Ngie. Control subjects were selected from 19 Ngie villages. Potential cases of people with epilepsy (PWE) were identified through a questionnaire applied by trained field workers, using history of epileptic seizures as a key indicator. Blood samples were taken from all consenting individuals by finger prick, stored in StabilZyme Select, and assayed for antibodies to T. solium in an Atlanta based reference laboratory.

RESULTS

We accrued 249 patients with epilepsy, of whom 237 met the inclusion criteria, and 245 age-matched controls. There was no significant difference in seropositivity to T. solium between those individuals with epilepsy (5%) and controls (4.9%).

CONCLUSIONS

Our data do not support the hypothesis that epilepsy is associated with seropositivity to T. solium. It is highly unlikely that cysticercosis plays a causative role in the high prevalence of epilepsy in this region of Cameroon.

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.

Multicenter transversal two-phase study to determine a national prevalence of epilepsy in Algeria

BACKGROUND/AIMS

The prevalence of epilepsy in Algeria is unknown. The aims of this multicenter transversal study were to determine the national prevalence and clinical characteristics of epilepsy in the Algerian population.

METHODS

This two-phase study was conducted in 5 circumscriptions and included 8,046 subjects aged over 2 months who attended the randomly selected public and private primary care clinics. In the phase 1 study, a questionnaire was submitted to the sample of patients. In the phase 2 study, all potentially epileptic people were examined by neurologists and a second questionnaire was submitted, eventually assessed by appropriate investigations.

RESULTS

Sixty-seven patients were identified as having active epilepsy, giving a crude prevalence ratio of 8.32 per 1,000 (95% CI, 6.34-10.3) and an age-adjusted prevalence ratio of 8.9 per 1,000. The highest age-specific ratio was found in patients aged 10-19 years (16.92 per 1,000). Generalized seizures (68.7%) were more common than partial seizures (29.8%). Perinatal injuries were the major leading putative causes (11.9%).

CONCLUSION

The prevalence of epilepsy of 8.32 determined in this study is relatively high. These results provide new epidemiological data and suggest that epilepsy remains an important public health issue to consider in Algeria.

Epilepsy in Tanzanian children: association with perinatal events and other risk factors

Purpose

To define the prevalence and risk factors for epilepsy in children in a rural district of Tanzania by conducting a community-based case–control study.

Methods

Children aged 6–14 years with active epilepsy (at least two unprovoked seizures in the last 5 years) were identified in a cross-sectional survey in Tanzania. Cases were compared with age-matched controls.

Key Findings

Overall 112 children with epilepsy (CWE) were identified; the unadjusted prevalence of epilepsy was 2.91 per 1,000 (95% confidence interval [95% CI] 2.4–3.5). The main seizure types were focal motor with secondary generalization in 73 (65.2%) of 112 and generalized convulsive seizures in 19 (16.9%) of 112. Adverse perinatal events were present in 16 (14%) of 112 cases but in no controls. In multivariate analysis, epilepsy was associated with number of parents who were resident at home (odds ratio [OR] 6.2 for none vs. both resident, 95% CI 1.5–25.5), history of adverse perinatal events (OR 14.9, 95% CI 1.4–151.3), family history of afebrile seizures (OR 5.7, 95% CI 1.0–27.5), and poor scholastic attainment (OR 8.6, 95% CI 4.0–18.4). Electroencephalography (EEG) and computed tomography (CT) scans were abnormal in 44 (44%) of 101 and 26 (29%) of 90 cases, respectively. Overall, 98 (88%) of 112 cases had focal features on assessment.

Significance

In this study from sub-Saharan Africa, CWE predominantly had focal features that support the suggestion that most epilepsy in this region has a symptomatic etiology. Adverse perinatal events were strongly associated with epilepsy. Genetic and social factors may also be important. Epilepsy may be preventable in a significant proportion of children with better antenatal and perinatal care.

Investigating epilepsy in Africa: 10 years of data collection using a standardized questionnaire in 2,269 peoples with epilepsy

PURPOSE

The need for comparable epidemiologic data on epilepsy from various locations in tropical areas has led in 1994 to the creation of a questionnaire able to standardize information. The Limoges' questionnaire was created to collect information independently of the objectives of each survey performed, and since it has been employed in various continents under tropics latitude. In Africa between 1994 and 2004, 13 epidemiologic surveys in 12 countries were performed by this means. Authors of these works were solicited to communicate their raw data on people with epilepsy (PWE).

METHODS

Information collected was aggregated in a database upon which operations of data management were processed. Undernutrition status was determined using an anthropologic method, according World Health Organization (WHO) recommendations. Factors associated with undernutrition and absence of treatment by phenobarbitone were searched for by using multivariate logistic regression.

KEY FINDINGS

Information about 2,269 PWE was collected. Mean treatment gap and undernutrition were determined, respectively, to be 30.6% [95% confidence interval (95% CI) 28.7-32.6] and 25.4% (95% CI 22.7-28.2). Factors significantly associated with undernutrition and not being treated with phenobarbitone were determined.

SIGNIFICANCE

Despite the different purposes of each study, we were able to pool information in order to characterize and study particular traits of PWE in Africa. Some items of particular importance should be collected systematically and will be highlighted in a newer version of this questionnaire. Because many surveys were undertaken using this tool in tropical areas, a backward compatibility should be ensured.

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.

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.

Seroprevalence of cysticercosis in children and young adults living in a helminth endemic community in leyte, the Philippines

Cysticercosis is a significant public health problem in countries where pigs are raised for consumption and remains an important cause of neurological disease worldwide. The Philippines is considered an endemic area for cysticercosis because cases in both humans and pigs have been reported; however, epidemiologic information stays limited. We conducted a pilot survey of the seroprevalence of human cysticercosis in a village in Leyte, the Philippines, by measuring antibody specific for Taenia solium cyst-fluid antigen. There were 497 subjects aged 7–30 years in our study and most subjects were infected with one or more helminths. The overall cysticercosis seroprevalence in this population was 24.6% (95% CI: 20.82% ~ 28.58%) with no significant difference based on age, sex, or other helminth coinfection status. Although the sample may not be representative of the whole community, the findings suggest that cysticercosis is a significant, but underrecognized public health concern in the Philippines.

Epilepsy and neurocysticercosis in sub-Saharan Africa

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

Epilepsy is not caused by cysticercosis in The Gambia

OBJECTIVE

To determine whether epilepsy is caused by Taenia solium cysticercosis in The Gambia.

METHODS

Case-control study testing samples collected from 210 people with epilepsy and 420 matched controls by sex and age +/-5 years from 69 different places around the country during the period October 2008-March 2009. All serum samples were subjected to an antigen detection ELISA (Ag-ELISA) and electro-immunotransfer blot (EITB), and the seropositives were further CT-scanned to determine the presence of cysticerci in the brain.

RESULTS

Although not significantly different (P = 0.668), circulating Taenia antigen was found by Ag-ELISA in 1.4% (95% CI: 0.3-4.1) of people with epilepsy and in 1.9% (95% CI: 0.8-3.7) of the controls. A non-significant (P = 0.4718) odds ratio of association 0.75 (95% CI: 0.13-3.15) between epilepsy and the presence of Taenia antigens was found. All 630 serum samples turned out seronegative by the EITB test. There were no intracranial cysts or cyst-like structures detected among the nine CT-scanned Ag-ELISA seropositives.

CONCLUSION

Epilepsy appears not to be caused by cysticercosis in The Gambia.

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.

Accuracy of serological testing for the diagnosis of prevalent neurocysticercosis in outpatients with epilepsy, Eastern Cape Province, South Africa

BACKGROUND

Few studies have estimated prevalence of neurocysticercosis (NCC) among persons with epilepsy in sub-Saharan Africa. While the limitations of serological testing in identification of NCC are well known, the characteristics of persons who are misdiagnosed based on serology have not been explored. The first objective of this pilot study was to estimate the prevalence of NCC in epilepsy outpatients from an area of South Africa endemic for cysticercosis. The second objective was to estimate the accuracy of serological testing in detecting NCC in these outpatients and characterize sources of disagreement between serology and neuroimaging.

METHODOLOGY/PRINCIPAL FINDINGS

All out-patients aged 5 or older attending the epilepsy clinic of St. Elizabeth's Hospital in Lusikisiki, Eastern Cape Province, between July 2004 and April 2005 were invited to participate. Epidemiological data were collected by local study staff using a standardized questionnaire. Blood samples were tested by ELISA for antibody and antigen for Taenia solium. Four randomly chosen, consenting participants were transported each week to Mthatha for brain CT scan. The proportion of persons with epilepsy attending St. Elizabeth clinic with CT-confirmed NCC was 37% (95% CI: 27%-48%). Using CT as the gold standard, the sensitivity and specificity of antibody testing for identifying NCC were 54.5% (36.4%-71.9%) and 69.2% (52.4%-83.0%), respectively. Sensitivity improved to 78.6% (49.2%-95.3%) for those with active lesions. Sensitivity and specificity of antigen testing were considerably poorer. Compared to false negatives, true positives more often had active lesions. False positives were more likely to keep pigs and to have seizure onset within the past year than were true negatives.

CONCLUSIONS/SIGNIFICANCE

The prevalence of NCC in South African outpatients with epilepsy is similar to that observed in other countries where cysticercosis is prevalent. Errors in classification of NCC using serology alone may reflect the natural history of NCC.

Meta-analysis of the association between cysticercosis and epilepsy in Africa

PURPOSE

The association between cysticercosis and epilepsy has been widely studied in Latin America and Asia and has proven to be one of the main causes of epilepsy. Despite high prevalences of both diseases in Africa, their association remains unclear. In this article we quantified the strength of the association between epilepsy and cysticercosis in Africa and we proposed some guidelines for future studies.

METHODS

We performed a systematic review of literature on cysticercosis (considered as exposure) and epilepsy (considered as the disease) and collected data from both cross-sectional and case-control studies. A common odds ratio was estimated using a random-effects meta-analysis model of aggregate published data.

RESULTS

Among 21 retrieved documents, 11 studies located in 8 African countries were included in the meta-analysis. Odds ratio of developing epilepsy when presenting cysticercosis (defined as Taenia solium seropositivity) ranged from 1.3-6.1. Overall, association between cysticercosis and epilepsy was found significant with a common odds ratio of 3.4 [95% confidence interval (CI) 2.7-4.3; p < 0.001].

DISCUSSION

The variability of the association found between the studies could be due to differences in study design or in pathogenesis of cysticercosis. Further studies should overcome identified problems by following some guidelines to improve epidemiologic and clinical assessment of the association. Better understanding of the relation between cysticercosis and epilepsy is a key issue in improving prevention of epilepsy in Africa.

Neglected tropical diseases in sub-saharan Africa: review of their prevalence, distribution, and disease burden

The neglected tropical diseases (NTDs) are the most common conditions affecting the poorest 500 million people living in sub-Saharan Africa (SSA), and together produce a burden of disease that may be equivalent to up to one-half of SSA's malaria disease burden and more than double that caused by tuberculosis. Approximately 85% of the NTD disease burden results from helminth infections. Hookworm infection occurs in almost half of SSA's poorest people, including 40-50 million school-aged children and 7 million pregnant women in whom it is a leading cause of anemia. Schistosomiasis is the second most prevalent NTD after hookworm (192 million cases), accounting for 93% of the world's number of cases and possibly associated with increased horizontal transmission of HIV/AIDS. Lymphatic filariasis (46-51 million cases) and onchocerciasis (37 million cases) are also widespread in SSA, each disease representing a significant cause of disability and reduction in the region's agricultural productivity. There is a dearth of information on Africa's non-helminth NTDs. The protozoan infections, human African trypanosomiasis and visceral leishmaniasis, affect almost 100,000 people, primarily in areas of conflict in SSA where they cause high mortality, and where trachoma is the most prevalent bacterial NTD (30 million cases). However, there are little or no data on some very important protozoan infections, e.g., amebiasis and toxoplasmosis; bacterial infections, e.g., typhoid fever and non-typhoidal salmonellosis, the tick-borne bacterial zoonoses, and non-tuberculosis mycobaterial infections; and arboviral infections. Thus, the overall burden of Africa's NTDs may be severely underestimated. A full assessment is an important step for disease control priorities, particularly in Nigeria and the Democratic Republic of Congo, where the greatest number of NTDs may occur.

Porcine cysticercosis in southeast Uganda: seroprevalence in kamuli and kaliro districts

The recent recognition of neurocysticercosis as a major cause of epilepsy in Uganda and changes in pig demography have lead to a need to better understand the basic epidemiology of Taenia solium infections in pigs and humans. Human exposure is a function of the size of the animal reservoir of this zoonosis. This is the first field survey for porcine cysticercosis to investigate the prevalence of antigen-positive pigs across an entire rural district of south-east Uganda. In our field surveys, 8.6% of 480 pigs screened were seropositive for the parasite by B158/B60 Ag-ELISA. In addition, of the 528 homesteads surveyed 138 (26%) did not have pit latrines indicating a high probability of pigs having access to human faeces and thus T. solium eggs. This study thus indicates the need for better data on this neglected zoonotic disease in Uganda, with a particular emphasis on the risk factors for infection in both pigs and humans. In this regard, further surveys of pigs, seroprevalence surveys in humans and an understanding of cysticercosis-related epilepsy are required, together with risk-factor studies for human and porcine infections.

Development of an immunobinding dot-blot assay as an alternative for the serodiagnosis of human cysticercosis

An immunobinding dot-blot assay (DBA) was developed on nitrocellulose paper for the serodiagnosis of human cysticercosis, using Cysticercus cellulosae as antigen. The DBA had an immunological sensitivity of 0.08 mg of antigen protein/ml; however, it showed cross-reactions with antigens of adult Taenia solium and Echinococcus granulosus, but not with Toxoplasma gondii and Entamoeba histolytica antigens. An enzyme-linked immunosorbent assay (ELISA) was used as the gold standard for obtaining the diagnostic validity of the DBA, giving 84.61%, 100.00%, 100.00% and 97.98% for epidemiological sensitivity, epidemiological specificity and positive and negative predictive values, respectively. There were no statistical differences between the two tests (P < 0.05, kappa = 0.907). This study showed that DBA is an alternative method for the serodiagnosis of human cysticercosis.

High prevalence of epilepsy in a village in the Littoral Province of Cameroon

PURPOSE

In the Littoral Province of Cameroon, in the Sanaga River Valley, a door-to-door epidemiological study was carried out in order to evaluate the prevalence of epilepsy in a small village located in a geographically isolated area, hyper-endemic for onchocerciasis. It was followed by an electro-clinical evaluation of patients and a case-control study.

METHODS

The study involved a three-phases design: in phase I, a screening questionnaire was administered, in phase II, the presence of epilepsy was confirmed with electro-clinical evaluation, and in phase III, risk factors for epilepsy, socio-economical factors and life habits were evaluated in patients and two matched controls for the age (+/-1 year) residents in the same village. Endemicity level of onchocerciasis was assessed in the village by measuring the prevalence of nodules in adult males aged >or=20 years (PNAM).

RESULTS

One hundred eighty-one subjects (100 male and 81 female) were examined (91.9% of the overall population). The crude prevalence rate of active epilepsy was 105 per 1000 pop (CI 95% 60-150) while the age-adjusted prevalence rate was 134.5 cases per 1000 pop (CI 95% 90-178). Seizures were classified as generalized in 10 patients (52.6%) and partial in nine (47.4%). In 17 patients EEG was recorded. Afterward the electro-clinical classification this distribution was inverted: generalized seizures occurred in 35.3% of cases and partial seizures in 64.7% of cases. The PNAM was 62.5%. The surveyed village was classified as hyper-endemic for onchocerciasis. Among risk factors, only positive family history for epilepsy was found (p=0.031). A sample pedigree of a family with 10 epileptic cases (4 included in the epidemiological study) was showed.

CONCLUSIONS

To our knowledge, this is the first door-to-door study that produce an adjusted prevalence rate on epilepsy in Cameroon. In according to studies done in Tanzania, Liberia, Uganda, and Ethiopia, our results (i.e., the high prevalence rate in a restricted area, the clinical characteristics of epileptic seizures, the positive family history for epilepsy and the type of pedigree of a family with epileptic patients) may be accounted for by the presence of an strong interaction between environmental and genetic factors in some circumscribed areas.