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.

Case-Control Study of Nodding Syndrome in Acholiland: Urinary Multi-Mycotoxin Screening.

This case-control study adds to the growing body of knowledge on the medical, nutritional, and environmental factors associated with Nodding Syndrome (NS), a seizure disorder of children and adolescents in northern Uganda. Past research described a significant association between NS and prior history of measles infection, dependence on emergency food and, at head nodding onset, subsistence on moldy maize, which has the potential to harbor mycotoxins. We used LC-MS/MS to screen for current mycotoxin loads by evaluating nine analytes in urine samples from age-and-gender matched NS cases (n = 50) and Community Controls (CC, n = 50). The presence of the three mycotoxins identified in the screening was not significantly different between the two groups, so samples were combined to generate an overall view of exposure in this community during the study. Compared against subsequently run standards, α-zearalenol (43 ± 103 µg/L in 15 samples > limit of quantitation (LOQ); 0 (0/359) µg/L), T-2 toxin (39 ± 81 µg/L in 72 samples > LOQ; 0 (0/425) µg/L) and aflatoxin M1 (4 ± 10 µg/L in 15 samples > LOQ; 0 (0/45) µg/L) were detected and calculated as the average concentration ± SD; median (min/max). Ninety-five percent of the samples had at least one urinary mycotoxin; 87% were positive for two of the three compounds detected. While mycotoxin loads at NS onset years ago are and will remain unknown, this study showed that children with and without NS currently harbor foodborne mycotoxins, including those associated with maize.

Nodding syndrome research revisited.

Nodding syndrome is one of several forms of onchocerciasis-associated epilepsy (OAE) seen among children in areas formerly hyperendemic for the transmission of Onchocerca volvulus. These forms of epilepsy are highly prevalent and clustered in certain villages located close to blackfly (Diptera: Simuliidae) breeding sites. OAE presents with a wide spectrum of seizures, including generalized tonic-clonic and head nodding seizures, impaired cognitive function, growth stunting and delayed puberty. In 2014, the present authors published a perspective paper in this journal which hypothesized that nodding syndrome may be caused by either a neurotropic virus transmitted by blackflies or an endosymbiont present within the O. volvulus parasite. Seven years later, this critical review presents progress in nodding syndrome research, and assesses whether it is still plausible that a neurotropic virus or endosymbiont could be the cause.

The Pathogenesis of Nodding Syndrome.

Nodding syndrome is a rare, enigmatic form of pediatric epilepsy that has occurred in an epidemic fashion beginning in the early 2000s in geographically distinct regions of Africa. Despite extensive investigation, the etiology of nodding syndrome remains unclear, although much progress has been made in understanding the pathogenesis of the disease, as well as in treatment and prevention. Nodding syndrome is recognized as a defined disease entity, but it is likely one manifestation along a continuum of Onchocerca volvulus-associated neurological complications. This review examines the epidemiology of nodding syndrome and its association with environmental factors. It provides a critical analysis of the data that support or contradict the leading hypotheses of the etiologies underlying the pathogenesis of the syndrome. It also highlights the important progress made in treating and preventing this devastating neurological disease and prioritizes important areas for future research.

Nodding Syndrome: The Unresolved Mystery of a Pediatric Disease in Sub-Saharan Africa.

Nodding syndrome is a mysterious neurologic illness of unknown etiology, presenting with distinctive clinical features often at early age. Currently, it affects children in restricted geographical areas in South Sudan, Northern Uganda and Southern Tanzania and is associated with high mortality and morbidity, especially in the children with severe disease. In this paper, we will give an outline of what is known about nodding syndrome with respect to epidemiology, clinical presentation, etiology and treatment. In addition, a possible approach to resolving the mystery is presented.

"Those who died are the ones that are cured". Walking the political tightrope of Nodding Syndrome in northern Uganda: Emerging challenges for research and policy.

BACKGROUND: Nodding Syndrome was first reported from Tanzania in the 1960s but appeared as an epidemic in Northern Uganda in the 1990s during the LRA civil war. It is characterized by repetitive head nodding, often followed by other types of seizures, developmental retardation and growth faltering with onset occurring in children aged 5-15 years. More than 50 years after the first reports, the aetiology remains unknown and there is still no cure. The recent hypothesis that Nodding Syndrome is caused by onchocerciasis also increases the relevance of onchocerciasis control. Northern Uganda, with its unique socio-political history, adds challenges to the prevention and treatment for Nodding Syndrome. This article aims to show how and why Nodding Syndrome has been politicised in Uganda; how this politicisation has affected health interventions including research and dissemination; and, the possible implications this can have for disease prevention and treatment. METHODOLOGY: Ethnographic research methods were used triangulating in-depth interviews, focus group discussions, informal conversations and participant observation, for an understanding of the various stakeholders' perceptions of Nodding Syndrome and how these perceptions impact future interventions for prevention, treatment and disease control. PRINCIPAL FINDINGS: Distrust towards the government was a sentiment that had developed in Northern Uganda over several decades of war and was particularly linked to the political control and ethnic divisions between the north and south. This coincided with the sudden appearance of Nodding Syndrome, an unknown epidemic disease of which the cause could not be clearly identified and optimal treatment had not clearly been established. Additionally, the dissemination of the inconclusive results of research conducted in the area lacked sufficient community involvement which further fueled this political distrust. Disease perceptions revolved around rumours that the entire Acholi ethnic group of the north would be annihilated, or that international researchers were making money by stealing study samples. This discouraged some community members from participating in research or from accepting the mass drug administration of ivermectin for prevention and treatment of onchocerciasis. Such rumour and distrust led to suspicions concerning the integrity of the disseminated results, which may negatively impact future disease management and control interventions. CONCLUSIONS AND RECOMMENDATIONS: Trust must be built up gradually through transparency and by de-politicising interventions. This can be done by engaging the community at regular intervals during research and data collection and the dissemination of results in addition to involvement during service delivery for prevention and treatment. Maintaining a regular feedback loop with the community will help control rumours, build trust, and improve the preparations for adequate dissemination.

The effect of bi-annual community-directed treatment with ivermectin on the incidence of epilepsy in onchocerciasis endemic villages in South Sudan: a study protocol.

BACKGROUND: Nodding syndrome (NS) is a devastating epileptic illness of unknown aetiology mainly affecting children 5-15 years of age. Head nodding distinguishes NS from other forms of epilepsy. Other manifestations of the illness include mental and physical growth retardation. Many children die as a result of falling in fires or drowning. Recently, it was shown that NS is only one of the phenotypic presentations of onchocerciasis associated epilepsy (OAE). Despite the strong epidemiological association between epilepsy and onchocerciasis, the causal mechanism is unknown. After implementation of bi-annual community directed treatment with ivermectin (CDTi) and larviciding of rivers in northern Uganda, new cases of NS have ceased, while new cases continue to emerge in South Sudanese onchocerciasis-endemic areas with an interrupted CDTi programme. This study is designed to evaluate the potential effects of bi-annual CDTi on reducing the incidence of NS/OAE in onchocerciasis-endemic areas in South Sudan. METHODS: A pre-intervention door-to-door population-based household survey will be conducted in selected onchocerciasis-endemic villages in Mundri and Maridi Counties, which have a high prevalence of epilepsy. Using a validated questionnaire, the entire village will be screened by community research assistants for suspected epilepsy cases. Suspected cases will be interviewed and examined by a trained clinical officer or medical doctor who will confirm or reject the diagnosis of epilepsy. Bi-annual CDTi will be implemented in the villages and a surveillance system for epilepsy set up. By implementing an epilepsy onchocerciasis awareness campaign we expect to obtain > 90% CDTi coverage of eligible individuals. The door-to-door survey will be repeated two years after the baseline survey. The incidence of NS/OAE will be compared before and after bi-annual CDTi. DISCUSSION: Our study is the first population-based study to evaluate the effect of bi-annual CDTi to reduce the incidence of NS/OAE. If the study demonstrates such a reduction, these findings are expected to motivate communities in onchocerciasis-endemic regions to participate in CDTi, and will encourage policy makers, funders and other stakeholders to increase their efforts to eliminate onchocerciasis.

Could nodding syndrome in Northern Uganda be a form of autism spectrum disorder? an observational study design.

INTRODUCTION: Nodding syndrome (NS) is associated with high anion gap, biotinidase and acetyl carnitine deficiency, vitamin B6 and D deficiency and internal displacement. The objective of this study was to conduct a metabolic analysis on NS children and review literature on its similarities with ASD. METHODS: We conducted biochemical analysis on blood and urine of NS children at Hope for HumaNs (HfH) centre in 2014 and reviewed literature on its similarities with ASD. Ethical approval was obtained from an IRB. Data analysis was conducted using STATA version 12 and a p-value less than 0.05 was considered significant. RESULTS: We found biotinidase deficiency in NS with a mean 1.98 95% CI(1.61, 2.34; p < 0.001); Acetyl carnitine deficiency 16.92 95% CI(16.10,17.75; p<0.001); Low BMI-for-age 16.92 95% CI(16.10,17.75; p = 0.42); Age 14.08 95% CI(0.78,4.660; p = 0.007); IDP duration 4.82 95% CI(4.48, 5.21; p = 0.92); Age at NS onset 8.02 95% CI(7.03, 9.01; p = 0.001); NS associated with multiple nodding episodes (χ2)=22.15, p=0.005; NS siblings with NS (χ2) = 9.68, p = 0.004; NS were in IDPs (χ2) = 22.15, p = 0.005. CONCLUSION: These findings are indicative that NS is associated with biotinidase and acetyl carnitine deficiency, IDPs, and environmental exposures. There are no new cases of NS reported by Ugandan MOH and WHO since 2012 when the IDP camps were disbanded and communities resettled in their own communities and feed on their own grown foods. Perhaps NS may be akin to Autism Spectrum Disorder (ASD). This finding will help support all efforts towards the treatment and rehabilitation of NS children.

Is nodding syndrome in northern Uganda linked to consumption of mycotoxin contaminated food grains?

OBJECTIVE: Nodding syndrome (NS) is a type of epilepsy characterized by repeated head-nodding seizures that appear in previously healthy children between 3 and 18 years of age. In 2012, during a WHO International Meeting on NS in Kampala, Uganda, it was recommended that fungal contamination of foods should be investigated as a possible cause of the disease. We therefore aimed to assess whether consumption of fungal mycotoxins contributes to NS development. RESULTS: We detected similar high levels of total aflatoxin and ochratoxin in mostly millet, sorghum, maize and groundnuts in both households with and without children with NS. Furthermore, there was no significant association between concentrations of total aflatoxin, ochratoxin and doxynivalenol and the presence of children with NS in households. In conclusion, our results show no supporting evidence for the association of NS with consumption of mycotoxins in contaminated foods.

Could Nodding Syndrome (NS) in Northern Uganda be an environmentally induced alteration of ancestral microbiota?

Hippocrates stated in 460-C.370 BC that, "All diseases begin in the Gut." This statement may be beginning to have meanings in the advent of new diseases such as Nodding Syndrome (NS) and Autism Spectrum Disorder (ASD). Interestingly, a recent publication from China in the journal of microbiology in 2017 suggests that high grain diet had dynamically shifted the composition of mucosa-associated microbiota and induced mucosal Injuries in the colon of Sheep. NS is a devastating childhood neurological disorder characterized by atonic seizure, cognitive impairment, head nodding, wasting and stunted growth. In addition, NS in Northern Uganda is clustered in time (those who were in IDPs), in space (discretely observed on either sides of the two rivers of Aswa and Pager) and in person (onset mainly between the ages of 5-15 years) and therefore exhibits spatial temporality. The first case of NS was noticed in Kitgum district in 1997, one year after the reported displacement of that community into IDP. Prior to that internal displacement, there were no reported cases of NS. The same scenario occurred in the IDPs of Odek, Gulu district where the population was displaced into IDPs in 2001 and approximately a year later in 2002, cases of NS began to appear. In the IDPs, children that eventually developed NS fed nearly exclusively on food ration provided by relief agencies and roughly a year later, cases of NS began to appear. In the other East African countries, there were no reported cases of NS prior to internal displacement and dependence on food ration. The observed common factors in the three East African regions where NS occurs at endemic proportion are perhaps: Internal displacement and feeding on relief food. These researchers suggest that NS may have perhaps resulted from dietary and environmental factors during IDPs which may have been foreign to their GIT and links this observation to the concept of microbiota-gut-brain axis.

Nodding Syndrome in the Spotlight - Placing Recent Findings in Perspective.

Nodding syndrome (NS) is a debated scientific topic. A recently published study suggests that NS is an autoimmune disorder based on findings of cross-reacting antibodies between neuronal structures and a protein present in Onchocerca volvulus (OV). In our opinion, the proposed causal relationship between OV infection and NS has yet to be demonstrated and, instead, OV infection in NS may be opportunistic.

Nakalanga Syndrome: Clinical Characteristics, Potential Causes, and Its Relationship with Recently Described Nodding Syndrome.

Nakalanga syndrome is a condition that was described in Uganda and various other African countries decades ago. Its features include growth retardation, physical deformities, endocrine dysfunction, mental impairment, and epilepsy, amongst others. Its cause remains obscure. Nodding syndrome is a neurological disorder with some features in common with Nakalanga syndrome, which has been described mainly in Uganda, South Sudan, and Tanzania. It has been considered an encephalopathy affecting children who, besides head nodding attacks, can also present with stunted growth, delayed puberty, and mental impairment, amongst other symptoms. Despite active research over the last years on the pathogenesis of Nodding syndrome, to date, no convincing single cause of Nodding syndrome has been reported. In this review, by means of a thorough literature search, we compare features of both disorders. We conclude that Nakalanga and Nodding syndromes are closely related and may represent the same condition. Our findings may provide new directions in research on the cause underlying this neurological disorder.

Reduced plasma concentrations of vitamin B6 and increased plasma concentrations of the neurotoxin 3-hydroxykynurenine are associated with nodding syndrome: a case control study in Gulu and Amuru districts, Northern Uganda.

INTRODUCTION: Nodding syndrome was first reported in Uganda in 2003 among internally displaced populations. Risk factors for the syndrome remain unknown. We therefore explored vitamin B6 deficiency and resulting high 3-hydroxykynurenine (3-HK) levels as risk factor for nodding syndrome in Northern Uganda. METHODS: Case-control study conducted in Gulu and Amuru districts. Cases were children/young adults with nodding syndrome. Healthy children/young adults were recruited as controls from same community as cases. Data on socio-demographic and other risk factors was collected using questionnaires. Whole blood was collected in EDTA tubes for assay of 3-HK and vitamin B6 using sandwich ELISA. Conditional logistic regression model was used to assess associations. RESULTS: 66 cases and 73 controls were studied. Factors associated with nodding syndrome were being positive for 3-HK (AOR=4.50, p=0.013), vitamin B6 concentration below mean (AOR=7.22, P=0.001), child being taken care of by mother only (AOR=5.43, p=0.011), child being taken care of by guardian (AOR=5.90, p=0.019) and child consuming relief food at weaning (AOR=4.05, p=0.021). CONCLUSION: Having low vitamin B6 concentration which leads to a build up of 3-hydroxykynurenine concentration in cases as a main risk factor. Therefore, cases should be treated with vitamin B6 and community members should be sensitise to ensure adequate dietary intake of vitamin B6 so that the risk of nodding syndrome among children is averted. We encourage future prospective intervention study to be conducted to assess the effect of low vitamin B6 on the development of nodding syndrome via raised 3-HK concentration.

Environmental, dietary and case-control study of Nodding Syndrome in Uganda: A post-measles brain disorder triggered by malnutrition?

Nodding Syndrome (NS) is an epileptic encephalopathy characterized by involuntary vertical head nodding, other types of seizures, and progressive neurological deficits. The etiology of the east African NS epidemic is unknown. In March 2014, we conducted a case-control study of medical, nutritional and other risk factors associated with NS among children (aged 5-18years) of Kitgum District, northern Uganda (Acholiland). Data on food availability, rainfall, and prevalent disease temporally related to the NS epidemic were also analyzed. In NS Cases, the mean age of reported head nodding onset was 7.6years (range 1-17years). The epidemiologic curve of NS incidence spanned 2000-2013, with peaks in 2003 and 2008. Month of onset of head nodding was non-uniform, with all-year-aggregated peaks in April and June when food availability was low. Families with one or more NS Cases had been significantly more dependent on emergency food and, immediately prior to head nodding onset in the child, subsistence on moldy plant materials, specifically moldy maize. Medical history revealed a single significant association with NS, namely prior measles infection. NS is compared with the post-measles disorder subacute sclerosing panencephalitis, with clinical expression triggered by factors associated with poor nutrition.

Is nodding syndrome an Onchocerca volvulus-induced neuroinflammatory disorder? Uganda's story of research in understanding the disease.

Nodding syndrome is a devastating neurological disorder, mostly affecting children in eastern Africa. An estimated 10000 children are affected. Uganda, one of the most affected countries, set out to systematically investigate the disease and develop interventions for it. On December 21, 2015, the Ministry of Health held a meeting with community leaders from the affected areas to disseminate the results of the investigations made to date. This article summarizes the presentation and shares the story of studies into this peculiar disease. It also shares the results of preliminary studies on its pathogenesis and puts into perspective an upcoming treatment intervention. Clinical and electrophysiological studies have demonstrated nodding syndrome to be a complex epilepsy disorder. A definitive aetiological agent has not been established, but in agreement with other affected countries, a consistent epidemiological association has been demonstrated with infection by Onchocerca volvulus. Preliminary studies of its pathogenesis suggest that nodding syndrome may be a neuroinflammatory disorder, possibly induced by antibodies to O. volvulus cross-reacting with neuron proteins. Histological examination of post-mortem brains has shown some yet to be characterized polarizable material in the majority of specimens. Studies to confirm these observations and a clinical trial are planned for 2016.

Nodding syndrome-a new hypothesis and new direction for research.

Nodding syndrome (NS) is an unexplained neurological illness that mainly affects children aged between 5 and 15 years. NS has so far been reported from South Sudan, northern Uganda, and Tanzania, but in spite of extensive investigations, the aetiology remains unknown. We hypothesize that blackflies (Diptera: Simuliidae) infected with Onchocerca volvulus microfilariae may also transmit another pathogen. This may be a novel neurotropic virus or an endosymbiont of the microfilariae, which causes not only NS, but also epilepsy without nodding. This hypothesis addresses many of the questions about NS that researchers have previously been unable to answer. An argument in favour of the hypothesis is the fact that in Uganda, the number of new NS cases decreased (with no new cases reported since 2013) after ivermectin coverage was increased and with the implementation of a programme of aerial spraying and larviciding of the large rivers where blackflies were breeding. If confirmed, our hypothesis will enable new strategies to control NS outbreaks.

Nodding syndrome or disease? On the conceptualization of an illness-in-the-making.

OBJECTIVE: To explore processes of conceptualizing nodding syndrome (NS), an unknown illness which has been reported to affect thousands of children in post-conflict northern Uganda, in South Sudan and in Tanzania. DESIGN: This qualitative study comprised 40 in-depth interviews with affected families, health workers and politicians during five months of fieldwork in northern Uganda and a review of available reports, newspapers and academic literature on NS. In addition, observations have been made at treatment centers and during outreaches and meetings. Focus is put on how meanings of key terms related to NS are produced and negotiated. Attention is being paid to the circulation of different discourses and explanatory models. RESULTS: Discourses and explanatory models play an active role in the conceptualization of illness, as much by medical personnel as by affected families and the media. The prominent use of biomedical terms in the academic discourse on NS is striking; links are suggested with onchocerciasis and epilepsy. In contrast, the local discourse associates NS with social issues. The illness experiences are connected to the trauma of past conflict, to poverty and to (region-bound) frustration over neglect. The cultural significance of physical symptoms raises the question of the impact of culture on health. CONCLUSION: By only looking at the biomedical significance of this new syndrome, we will miss important aspects of how this illness is being experienced and understood. In our future dealings with NS, we will have to consider and re-conceive the relation between culture and neurobiology.

Nodding syndrome in Mundri county, South Sudan: environmental, nutritional and infectious factors.

BACKGROUND: Nodding Syndrome is a seizure disorder of children in Mundri County, Western Equatoria, South Sudan. The disorder is reported to be spreading in South Sudan and northern Uganda. OBJECTIVE: To describe environmental, nutritional, infectious, and other factors that existed before and during the de novo 1991 appearance and subsequent increase in cases through 2001. METHODS: Household surveys, informant interviews, and case-control studies conducted in Lui town and Amadi village in 2001-2002 were supplemented in 2012 by informant interviews in Lui and Juba, South Sudan. RESULTS: Nodding Syndrome was associated with Onchocerca volvulus and Mansonella perstans infections, with food use of a variety of sorghum (serena) introduced as part of an emergency relief program, and was inversely associated with a history of measles infection. There was no evidence to suggest exposure to a manmade neurotoxic pollutant or chemical agent, other than chemically dressed seed intended for planting but used for food. Food use of cyanogenic plants was documented, and exposure to fungal contaminants could not be excluded. CONCLUSION: Nodding Syndrome in South Sudan has an unknown etiology. Further research is recommended on the association of Nodding Syndrome with onchocerciasis/mansonelliasis and neurotoxins in plant materials used for food.