Ictal Electroencephalographic Characteristics of Nodding Syndrome: A Comparative Case-Series from South Sudan, Tanzania, and Uganda.

Nodding syndrome (NS) is a poorly understood form of childhood-onset epilepsy that is characterized by the pathognomonic ictal phenomenon of repetitive vertical head drops. To evaluate the underlying ictal neurophysiology, ictal EEG features were evaluated in nine participants with confirmed NS from South Sudan, Tanzania, and Uganda and ictal presence of high frequency gamma oscillations on scalp EEG were assessed. Ictal EEG during the head nodding episode predominantly showed generalized slow waves or sharp-and-slow wave complexes followed by electrodecrement. Augmentation of gamma activity (30-70 Hz) was seen during the head nodding episode in all the participants. We confirm that head nodding episodes in persons with NS from the three geographically distinct regions in sub-Saharan Africa share the common features of slow waves with electrodecrement and superimposed gamma activity. ANN NEUROL 2022;92:75-80.

Does the presence of a specialist doctor reduce the burden of disease in people with epilepsy in low-resource settings? A comparison of two epilepsy clinics in rural Tanzania.

BACKGROUND: With an estimated lifetime prevalence of epilepsy of 7.6 per 1,000 people, epilepsy represents one of the most common neurological disorders worldwide, with the majority of people with epilepsy (PWE) living in low-income and middle-income countries (LMICs). Adequately treated, up to 70 % of PWE will become seizure-free, however, as many as 85% of PWE worldwide, mostly from LMICs, do not receive adequate treatment. OBJECTIVE: To assess the impact of the presence of a neurologist on the management of PWE in Tanzania. METHODS: Two epilepsy clinics in rural Tanzania, one continuously attended by a neurologist, and one mainly attended by nurses with training in epilepsy and supervised intermittently by specialist doctors (neurologists/psychiatrists) were comparatively analyzed by multivariable linear and logistic regression models with regard to the outcome parameters seizure frequency, the occurrence of side effects of antiepileptic medication and days lost after a seizure. RESULTS: The presence of a neurologist significantly reduced the mean number of seizures patients experienced per month by 4.49 seizures (p < 0.01) while leading to an increase in the occurrence of reported side effects (OR: 2.15, p = 0.02). CONCLUSION: The presence of a neurologist may play a substantial role in reducing the burden of the disease of PWE in LMICs. Hence, specialist training should be encouraged, and relevant context-specific infrastructure established.

Characteristics of people with epilepsy in three Eastern African countries - a pooled analysis.

BACKGROUND: Epilepsy is one of the most common neurological disorders worldwide. Yet, its treatment gap is large in some areas and especially in sub-Saharan Africa data on clinical, radiological and semiological characteristics, as well as on treatment of persons with epilepsy (PWE) are still scarce. METHODS: We pooled data from four cross-sectional studies on epilepsy in eastern Africa. Two studies from Malawi and Uganda were community-based; two studies in Tanzania (urban Dar es Salaam and rural Haydom) were hospital-based. Clinical characteristics of PWE were assessed by the same questionnaire. Additionally, data on treatment were collected and computed tomography (CT) scans were performed. RESULTS: Overall, 1179 PWE were included in our analysis (581 (49.3%) female, median age 22 years (IQR 15-32 years)). Up to 25% of the patients had focal onset seizures. Those showed a higher rate of remarkable CT scan findings, with especially post-ischaemic and neurocysticercosis-associated lesions, compared to PWE with generalized onset seizures (35.1% vs. 20%). The majority of the patients experienced tonic-clonic seizures (70-85%). Only 67-78% of PWE received anti-seizure medication (ASM) treatment in the community-based studies, mostly monotherapy with phenobarbital, phenytoin or carbamazepine. Yet, underdosage was frequent and a large proportion of PWE received alternative non-ASM treatment consisting of herbal treatment (up to 83%) and/or scarification (up to 20%). CONCLUSIONS: Epilepsy is common in sub-Saharan Africa, often caused by neurocysticercosis or ischaemic strokes. PWE suffer from high seizure rates and subsequent injuries, as well as from socio-economic consequences due to insufficient ASM treatment. This pooled analysis illustrates the need for structural programmes for adequate identification, education, assessment and treatment of PWE in sub-Saharan Africa.

Febrile seizures in an urban Tanzanian population: lessons learned from a community-based random cluster survey.

OBJECTIVE: To analyse the cumulative incidence of febrile seizures, to evaluate the accuracy of our screening questionnaire and to describe clinical characteristics of children with febrile seizure in an urban population in Tanzania. METHODS: A large random cluster sampled population was screened for a febrile seizure history as part of a larger epilepsy study using a standardised questionnaire in a two-stage door-to-door survey in Tanzania. A subset of screen positive participants was further examined for confirmation of diagnosis and evaluation of clinical characteristics. RESULTS: Overall, 49 697 people were screened for a febrile seizure history of whom 184 (0.4%) screened positive. Women more commonly screened positive than men (112 [0.4%] vs. 72 [0.3%]). There was no marked difference between age groups or education. The positive predictive value of the screening tool was 37% (95% CI 24-51%) but its accuracy varied with the age of interviewed individuals. Cumulative incidence rates were estimated between 1.1% and 2.0% after adjusting for the inaccuracy of the screening tool. Most febrile seizures occurred before the age of two (65%) and most children had more than one episode (80%). A large proportion of children had complex febrile seizure (65%), often caused by malaria or respiratory infections. CONCLUSIONS: The community-based cumulative incidence of a febrile seizure history in an urban Tanzanian population was similar to rates reported from other rural populations after adjusting for the inaccuracy of our screening tool. Based on the integrated nature of the febrile seizure questionnaire, screening positivity rates may have been too low. This has implications for the design of future studies. The majority of cases had complex febrile seizures often associated with malaria. This has implications for clinical case management.

Early Mortality and Associated Factors among Patients with Stroke Admitted to a Large Teaching Hospital in Tanzania.

BACKGROUND: Stroke is a major cause of death worldwide and 85.5% of stroke deaths occur in low- and middle-income countries due to stroke. The aim of this study was to investigate correlates and predictors of 30-day mortality in stroke patients in urban Tanzania. METHODS: A prospective 30-day follow-up study was conducted at the Muhimbili National Hospital, Dar es Salaam, Tanzania. We recruited all patients with stroke seen at the Emergency Medicine Department and medical wards. Patients underwent medical history and physical examination including full neurological examination. For those who met the criteria for the diagnosis of stroke according to the World Health Organization, further data were collected, including cholesterol, creatinine, fasting blood glucose, full blood picture, human immunodeficiency virus serology, and electrocardiogram. Patients were followed up at 30 days from the date of stroke onset. The date and the cause of death of those participants who died within 30 days of stroke onset were recorded. RESULTS: A total of 224 patients were recruited into the study, with follow-up data available on 186 (83.0%). At 30 days post stroke, 124 patients (66.7%) were still alive. Mortality was significantly higher among stroke patients who were over 65 years of age. Of the 62 who died, 54% died of aspiration pneumonia and 21% of septicemia. Patients with infection were 4.4 times more likely to die than thosewithout (P = .001). CONCLUSIONS: Poststroke mortality rates were high. Many deaths were potentially preventable.

Community-based prevalence and clinical characteristics of febrile seizures in Tanzania.

BACKGROUND: The prevalence of febrile seizures (FSs) and epilepsy are often reported to be higher in sub-Saharan Africa. Furthermore, several studies describe complex features of FSs as risk factors for the development of subsequent epilepsy. METHODS: During the period from 2002 to 2004 door-to-door studies with supplementary data collection were conducted in three different areas of Tanzania, examining the prevalence of FSs in 7,790 children between the age of 2 mo and 7 y at the time of the interview. The information on the presence of FSs of 14,583 children, who at the time of the interview were younger than 15 y, was collected in order to describe reported seizures, if any. RESULTS: Overall, 160 children between 2 mo and 7 y with a prevalence rate of 20.5/1,000 (95% confidence interval: 17.5-23.9/1,000) met the criteria for FSs. The average age at onset was 2.2 (SD: 1.8) y and ~42% had complex FSs. Respiratory tract infections and malaria were the most frequent concomitant diseases. CONCLUSION: Our findings do not confirm the assumption of an increased prevalence of FSs in sub-Saharan Africa. However, the elevated number of complex FSs emphasizes the necessity of more reliable studies about FSs and its consequences.

A longitudinal study on nodding syndrome--a new African epilepsy disorder.

OBJECTIVES: Nodding syndrome (NS), a new epilepsy disorder of sub-Saharan Africa, has only recently been classified. In a study conducted in southern Tanzania in 2005, 62 patients with NS were analyzed in great detail. The present study, a follow-up investigation, was conducted to evaluate the progression of NS over time and to obtain serial electroencephalography (EEG) data. METHODS: Of the 62 NS patients, 53 (85.5%), the majority of whom were currently on some form of antiepileptic treatment, could be reevaluated in 2009 with a standardized questionnaire. A subset of these patients (25/53) underwent EEG investigation. RESULTS: In patients with "head nodding (HN) only" in 2005, 10 (43.5%) of 23 remained with the same diagnosis, whereas 5 (21.7%) of 23 had developed "HN plus" (i.e., HN and generalized tonic-clonic seizures). Six patients (26.1%) had seizures other than HN only, and two patients (8.7%) had fully recovered. In the "HN plus" group of 2005, 9 (30.0%) of 30 patients remained "HN plus," and 15 patients (50.0%) had seizures other than HN only. Four patients (13.3%) reverted to "HN only," and two patients (6.7%) stopped all seizures. In 11 (44.0%) of 25 patients, electroencephalography (EEG) showed generalized slowing. Six (54.6%) of these 11 abnormal EEG studies further showed generalized epileptiform discharges: (1) ictal electroencephalographic pattern with generalized 2.5 Hz spike and waves in two patients and (2) interictal bursts of 1.5-2 Hz spike and waves in four patients. SIGNIFICANCE: This follow-up study confirms that HN represents an epilepsy disorder, possibly of the atypical absence type with dynamic development over time.

Clinical features, proximate causes, and consequences of active convulsive epilepsy in Africa.

PURPOSE: Epilepsy is common in sub-Saharan Africa (SSA), but the clinical features and consequences are poorly characterized. Most studies are hospital-based, and few studies have compared different ecological sites in SSA. We described active convulsive epilepsy (ACE) identified in cross-sectional community-based surveys in SSA, to understand the proximate causes, features, and consequences. METHODS: We performed a detailed clinical and neurophysiologic description of ACE cases identified from a community survey of 584,586 people using medical history, neurologic examination, and electroencephalography (EEG) data from five sites in Africa: South Africa; Tanzania; Uganda; Kenya; and Ghana. The cases were examined by clinicians to discover risk factors, clinical features, and consequences of epilepsy. We used logistic regression to determine the epilepsy factors associated with medical comorbidities. KEY FINDINGS: Half (51%) of the 2,170 people with ACE were children and 69% of seizures began in childhood. Focal features (EEG, seizure types, and neurologic deficits) were present in 58% of ACE cases, and these varied significantly with site. Status epilepticus occurred in 25% of people with ACE. Only 36% received antiepileptic drugs (phenobarbital was the most common drug [95%]), and the proportion varied significantly with the site. Proximate causes of ACE were adverse perinatal events (11%) for onset of seizures before 18 years; and acute encephalopathy (10%) and head injury prior to seizure onset (3%). Important comorbidities were malnutrition (15%), cognitive impairment (23%), and neurologic deficits (15%). The consequences of ACE were burns (16%), head injuries (postseizure) (1%), lack of education (43%), and being unmarried (67%) or unemployed (57%) in adults, all significantly more common than in those without epilepsy. SIGNIFICANCE: There were significant differences in the comorbidities across sites. Focal features are common in ACE, suggesting identifiable and preventable causes. Malnutrition and cognitive and neurologic deficits are common in people with ACE and should be integrated into the management of epilepsy in this region. Consequences of epilepsy such as burns, lack of education, poor marriage prospects, and unemployment need to be addressed.

Nodding syndrome.

An epidemic illness characterized by head nodding associated with onchocerciasis has been described in eastern Africa since the early 1960s; we summarize published reports and recent studies. Onset of nodding occurs in previously healthy 5-15-year-old children and is often triggered by eating or cold temperatures and accompanied by cognitive impairment. Its incidence has increased in Uganda and South Sudan over the past 10 years. Four case-control studies identified modest and inconsistent associations. There were nonspecific lesions seen by magnetic resonance imaging, no cerebrospinal fluid inflammation, and markedly abnormal electroencephalography results. Nodding episodes are atonic seizures. Testing has failed to demonstrate associations with trypanosomiasis, cysticercosis, loiasis, lymphatic filariasis, cerebral malaria, measles, prion disease, or novel pathogens; or deficiencies of folate, cobalamin, pyridoxine, retinol, or zinc; or toxicity from mercury, copper, or homocysteine. There is a consistent enigmatic association with onchocerciasis detected by skin snip or serologic analysis. Nodding syndrome is an unexplained epidemic epilepsy.

Correction: Characteristics of people with epilepsy and Neurocysticercosis in three eastern African countries-A pooled analysis.

[This corrects the article DOI: 10.1371/journal.pntd.0010870.].

Epilepsy and nodding syndrome in association with an Onchocerca volvulus infection drive distinct immune profile patterns.

Previous studies have described the association of onchocerciasis (caused by Onchocerca volvulus) with epilepsy, including nodding syndrome, although a clear etiological link is still missing. Cases are found in different African countries (Tanzania, South Sudan, Uganda, Democratic Republic of the Congo, Central African Republic and Cameroon). In our study we investigated immunological parameters (cytokine, chemokine, immunoglobulin levels) in individuals from the Mahenge area, Tanzania, presenting with either epilepsy or nodding syndrome with or without O. volvulus infection and compared them to O. volvulus negative individuals from the same endemic area lacking neurological disorders. Additionally, cell differentiation was performed using blood smears and systemic levels of neurodegeneration markers, leiomodin-1 and N-acetyltyramine-O, ß-glucuronide (NATOG) were determined. Our findings revealed that cytokines, most chemokines and neurodegeneration markers were comparable between both groups presenting with epilepsy or nodding syndrome. However, we observed elevated eosinophil percentages within the O. volvulus positive epilepsy/nodding syndrome patients accompanied with increased eosinophilic cationic protein (ECP) and antigen-specific IgG levels in comparison to those without an O. volvulus infection. Furthermore, highest levels of NATOG were found in O. volvulus positive nodding syndrome patients. These findings highlight that the detection of distinct biomarkers might be useful for a differential diagnosis of epilepsy and nodding syndrome in O. volvulus endemic areas. Trial-registration: NCT03653975.

Characteristics of people with epilepsy and Neurocysticercosis in three eastern African countries-A pooled analysis.

BACKGROUND: Neurocysticercosis (NCC), a zoonotic disease caused by the pork tapeworm T. solium, represents one of the most common causes of secondary epilepsy but remains often undiagnosed due to lack of awareness and diagnostic facilities. METHODOLOGY: We pooled data from four cross-sectional studies on epilepsy and NCC in eastern Africa. Study sites were in Uganda, Malawi and in Tanzania (Dar es Salaam and Haydom). The study in Uganda and Malawi were community-based, the two studies in Tanzania were hospital-based. The same questionnaire was used for assessment of clinical characteristics of patients with epilepsy. Computed tomography (CT) scans and serological testing were performed in order to diagnose NCC. RESULTS: Overall, 1,179 people with epilepsy were included in our analysis. Of those, 941 PWE underwent CT scanning and were pooled for NCC analysis. Seventy patients were diagnosed with NCC, but NCC prevalence differed considerably between sites ranging from 2.0% (95%CI 0.4% to 3.6%) in Dar es Salaam to 17.5% (95%CI 12.4% to 22.6%) in Haydom. NCC prevalence did not show any association with sex but increased with age and was higher in rural than urban settings. In addition, being a farmer, non-Muslim, eating pork and living with pigs close by was associated with a higher NCC prevalence. PWE with NCC experienced their first epileptic seizure around 3 years later in life compared to PWE without NCC and their epileptic seizures seemed to be better controlled (p<0.001). There was no difference between focal onset seizures and focal signs on neurological examination in both groups (p = 0.49 and p = 0.92, respectively). The rT24H-EITB had a sensitivity for the detection of NCC of 70% (95% confidence interval [CI] 51 to 84%), the LLGP of 76% (95%CI 58 to 89%) and the antigen ELISA of 36% (95% CI 20 to 55%). CONCLUSIONS: NCC is prevalent among PWE in eastern Africa, although it may not be as common as previously stated. Demographic characteristics of PWE with NCC differed from those without NCC, but semiological characteristics and results on neurological examination did not differ compared to PWE without NCC. Interestingly, seizures seemed to be less frequent in PWE with NCC. Being aware of those differences and similarities may help triaging PWE for neuroimaging in order to establish a diagnosis of NCC.

Migraine attack frequency, duration, and pain intensity: disease burden derived from a community-based survey in northern Tanzania.

OBJECTIVE: One goal of the campaign "Lifting the burden: The global campaign against headache" is to highlight existing evidence about headache worldwide. In this context, the aim of our study was to report the migraine-related headache burden in northern Tanzania. METHODS: From December 2003 until June 2004 a community-based door-to-door survey was undertaken in northern Tanzania, using multistage cluster sampling. Based on the criteria of the International Headache Society, 7412 individuals were enrolled in this survey. RESULTS: Migraine patients' average annual attack frequency was 18.4 (n = 308, standard deviation [SD] ± 47.4) with a mean duration of 16.4 hours (SD ± 20.6). The average headache intensity per patient was 2.65 (SD ± 0.59) with a calculated loss of 6.59 (SD ± 26.7) working days per year. Extrapolation of data to the investigated population (n = 7412) resulted in annual migraine burden of 281.0 migraine days per 1000 inhabitants. CONCLUSIONS: To our knowledge, this study reports for the first time the burden that arises from migraine headache in a rural population of sub-Sahara Africa (SSA). As the presented migraine-related burden is considerable, we hope that our data will increase the awareness among local decision makers in allocating resources for treatment and research on headache.

Lifetime prevalence of epilepsy in urban Tanzania - A door-to-door random cluster survey.

OBJECTIVES: Epileptic seizures and epilepsy in urban settings of low-income and middle-income countries (LMIC) are largely under-researched, but their prevalence is necessary for good healthcare planning. This study aimed to determine the lifetime prevalence of epileptic seizures and epilepsy in urban Dar es Salaam. METHODS: Nearly 50,000 people in former Kinondoni district, Dar es Salaam, were screened for epileptic seizures using a set of nine questions. Answers to these nine questions were categorized into generalized, focal, and unspecified seizures. Screening positivity rates were adjusted for questionnaire inaccuracy using two scenarios to analyse true epilepsy prevalences. RESULTS: Overall, 1085 (2.23%) people fulfilled the criteria for ever having had at least one type of epileptic seizure. Two-hundred-ninety-six (0.60%) people screened positive for generalized seizures, 986 (2.02%) for focal seizures, and 32 (0.07%) for unspecified seizures. Women more commonly screened positive than men (2.61% versus 1.72%, p < 0.001), particularly for focal seizures (p < 0.001). Adjusting for different degrees of accuracy of the screening questionnaire yielded true lifetime prevalences for epilepsy of any type between 1.59% and 2.41%. We furthermore observed a considerable variation of screening positivity rates between wards in Kinondoni district (p < 0.001). CONCLUSION: The prevalence of epilepsy, based on a questionnaire survey in urban Tanzania, was higher than previously observed, probably due to the screening questionnaire, which contained questions specifically designed to identify focal seizures. Further studies on epileptic seizures/epilepsy are needed for urban settings in LMIC, preferably with an integrated follow-up of positive cases.

The role of Onchocerca volvulus in the development of epilepsy in a rural area of Tanzania.

INTRODUCTION: Several reports indicate high prevalences of both onchocerciasis and epilepsy in some regions of Africa. This raises the question of whether these diseases are associated. We therefore investigated people with epilepsy and/or onchocerciasis living in an area in Tanzania endemic for Onchocerca volvulus (O. volvulus). METHODS: We collected clinical information, skin snips, and blood from 300 individuals, and cerebrospinal fluid (CSF) from 197. Participants were allocated to 4 groups consisting of people with epilepsy and onchocerciasis (n=135), those with either epilepsy (n=61) or onchocerciasis only (n=35), and healthy individuals (n=69). Samples were evaluated for microfilaria, IgG4 antibodies against O. volvulus, O. volvulus antibody index (CSF/serum), and CSF routine parameters. Polymerase chain reaction (PCR) was performed on skin snips and CSF. RESULTS: No difference was found in microfilarial density between participants with and without epilepsy (P=0.498). The antibody index was raised in 2 participants. CSF PCR was negative in all samples tested. DISCUSSION: Our results do not give evidence of a relationship between O. volvulus and epilepsy. Despite the fact that 2 participants had raised antibody index, the existence of cerebral onchocerciasis caused by migration of microfilariae into the CSF appears unlikely. However, to date unexplored reactions to the infestation with O. volvulus causing epilepsy cannot be excluded.

Epilepsy and neurocysticercosis in rural Tanzania-An imaging study.

PURPOSE: In developing countries, neurocysticercosis (NCC) is a common cause of epilepsy. Most of the work on NCC and epilepsy has been compiled in Latin America. To date, comprehensive neuroimaging studies are missing in sub-Saharan Africa. METHODS: In our study, we interviewed 212 people with epilepsy (PWE) and performed cerebral computed tomography (CT) at the Haydom Lutheran Hospital in northern Tanzania. Control cerebral CT scans were selected from 198 consecutive individuals without epilepsy. Sera of PWE with lesions indicating NCC (n = 20), PWE without NCC lesions (n = 20), and healthy individuals (n = 20), as well as cerebrospinal fluid (CSF) samples of PWE with NCC lesions (n = 11) were investigated for anticysticercal antibodies. RESULTS: Definite NCC lesions were present in five (2.4%), lesions highly suggestive of NCC in 24 (11.3%), and lesions compatible with NCC in nine (4.2%) PWE. This compares to two (1.0%) people with definite NCC lesions, two (1.0%) with lesions highly suggestive of, and six (2.9%) with lesions compatible with NCC in the control group. NCC lesions were significantly more frequent in PWE compared to controls (p < 0.0001). CT results, and serum and CSF analysis taken together, we diagnosed 22 (10.4%) individuals with probable and 7 (3.3%) with definitive NCC in our cohort of PWE. CONCLUSION: For the first time in sub-Saharan Africa, we give evidence within a large-scale neuroimaging study that NCC, a so far neglected infectious disease, represents a major cause of epilepsy.

Taenia solium cysticercosis and taeniasis in urban settings: Epidemiological evidence from a health-center based study among people with epilepsy in Dar es Salaam, Tanzania.

In Africa, urbanization is happening faster than ever before which results in new implications for transmission of infectious diseases. For the zoonotic parasite Taenia solium, a major cause of acquired epilepsy in endemic countries, the prevalence in urban settings is unknown. The present study investigated epidemiological, neurological, and radiological characteristics of T. solium cysticercosis and taeniasis (TSCT) in people with epilepsy (PWE) living in Dar es Salaam, Tanzania, one of the fastest growing cities worldwide. A total of 302 PWE were recruited from six health centers in the Kinondoni district of Dar es Salaam. Serological testing for T. solium cysticercosis-antigen (Ag) and -antibodies (Abs) and for T. solium taeniasis-Abs was performed in all PWE. In addition, clinical and radiological examinations that included cranial computed tomography (CT) were performed. With questionnaires, demographic data from study populations were collected, and factors associated with TSCT were assessed. Follow-up examinations were conducted in PWE with TSCT. T. solium cysticercosis-Ag was detected in three (0.99%; 95% CI: 0-2.11%), -Abs in eight (2.65%; 95% CI: 0.84-4.46%), and taeniasis-Abs in five (1.66%; 95% CI: 0.22-3.09%) of 302 PWE. Six PWE (1.99%; 95% CI: 0.41-3.56%) were diagnosed with neurocysticercosis (NCC). This study demonstrates the presence of TSCT in Dar es Salaam, however, NCC was only associated with a few cases of epilepsy. The small fraction of PWE with cysticercosis- and taeniasis-Abs may suggest that active transmission of T. solium plays only a minor role in Dar es Salaam. A sufficiently powered risk analysis was hampered by the small number of PWE with TSCT; therefore, further studies are required to determine the exact routes of infection and risk behavior of affected individuals.

Clinical presentation of epilepsy in six villages in an onchocerciasis endemic area in Mahenge, Tanzania.

To describe the clinical manifestations of epilepsy and access to antiseizure treatment in Mahenge in Central Tanzania, an onchocerciasis endemic area with a high prevalence of epilepsy. A door-to-door epilepsy prevalence survey was conducted in four rural and two sub-urban villages. Trained community workers used five screening questions to identify persons suspected to have epilepsy. Such individuals were interviewed and examined by a neurologist or a medical doctor with additional training in epilepsy, and were tested for Onchocerca volvulus antibodies. A total of 221 out of 8,062 (2.74%) surveyed individuals were confirmed to have epilepsy. The median age at seizure onset was 12 years (interquartile range: 7-16). Seventy-nine persons with epilepsy (PWE) (36.1%) had a family member with epilepsy, which was a sibling in 52.1%. Tonic-clonic seizures (142 individuals; 64.2%) were the most common seizure type. Nodding seizures were reported in 12.7% of PWE; the majority of them living in rural villages. Persons with nodding seizures reported more frequent seizures, presented with more psychiatric symptoms, and more often had onchocerciasis antibodies than those with other seizure types. The high rate of individuals with a seizure onset at between seven and 16 years is characteristic of onchocerciasis-associated epilepsy (OAE). Of the PWE, 77.9% met the criteria for the clinical case definition of OAE. Eighty-three PWE (37.6%) were not taking any antiepileptic medication. Phenobarbital was the antiepileptic drug most commonly prescribed in 76.1% of treated PWE. The high prevalence of epilepsy in rural villages in Mahenge most likely is related to the high prevalence of OAE. To prevent children developing OAE, strengthening the onchocerciasis elimination programme in Mahenge is urgently needed. Moreover, a decentralised epilepsy treatment programme is also needed to provide uninterrupted access to affordable antiepileptic drugs for the many PWE living in rural villages in the Mahenge area.

Onchocerciasis-associated epilepsy: another piece in the puzzle from the Mahenge mountains, southern Tanzania.

In a study from the onchocerciasis-endemic area of Mahenge in southern Tanzania, Mmbando et al. [Inf Dis Poverty. 2018;7:64] demonstrate that in four selected villages the overall epilepsy prevalence was high, and significantly more elevated in the two villages of higher onchocerciasis endemicity compared to those of lower endemicity. This is replicating earlier findings from many other areas of tropical Africa. The authors are also providing data indicating that in the Mahenge focus, the prevalence of nodding syndrome may be related to that of onchocerciasis in the same way as epilepsy in general. The application of a clinical case definition for onchocerciasis-associated epilepsy (OAE) as used in the study of Mmbando et al. [Inf Dis Poverty. 2018;7:64] faces some difficulties; indeed, its precision in discerning cases of OAE from epilepsy due to other etiologies is not known, and it does not allow for a specific diagnosis in the individual patient. Because an operational surveillance tool for assessing the number of patients in the population could mean substantial advance for better estimating the burden of OAE, the proposed definition should be tried in different settings and its performance reviewed in the process.