Nodding syndrome since 2012: recent progress, challenges and recommendations for future research

In pursuit of a cure: The plural therapeutic landscape of onchocerciasis-associated epilepsy in Cameroon - A mixed methods study

BACKGROUND

A high prevalence of epilepsy has been observed in several onchocerciasis-endemic villages in the Sanaga River basin, Cameroon. Recent studies suggest that ivermectin, a drug that is distributed annually with the aim of eliminating onchocerciasis, may have a protective effect against acquiring onchocerciasis-associated epilepsy (OAE). This study, therefore, provides an in-depth understanding of both the complex therapeutic landscape for epilepsy as well as the experiences related to the 'community-directed treatment with ivermectin' (CDTI) campaign in order to identify a more trenchant path forward in the fight against epilepsy.

METHODOLOGY/PRINCIPAL FINDINGS

Based on a mixed methods study combining a qualitative strand with a quantitative survey, we found that epilepsy was perceived to have had an epidemic emergence in the past and was still considered an important health issue in the study area. Socio-economic status, availability and accessibility of drugs and practitioners, as well as perceived aetiology shaped therapeutic itineraries for epilepsy, which included frequenting (in)formal biomedical health care providers, indigenous and/or faith healing practitioners. Ivermectin uptake for onchocerciasis was generally well known and well regarded. The CDTI faced structural and logistical bottlenecks undermining equal access and optimal adherence to the drug.

CONCLUSIONS/SIGNIFICANCE

Locally accessible, uninterrupted, sustainable and comprehensive health-service delivery is essential to help alleviate the epilepsy burden on afflicted households. Addressing structural challenges of CDTI and communicating the potential link with epilepsy to local populations at risk could optimize the uptake of this potentially significant tool in OAE prevention.

Antiparasitic antibiotics from Japan

Antibiotics are microbial secondary metabolites and they are important for the treatment of infectious diseases. Japanese researchers have made a large contribution to studies of antibiotics, and they have also been important in the discovery of antiparasitic antibiotics. Satoshi Ōmura received the Nobel Prize in 2015 for the "discoveries concerning a novel therapy against infections caused by roundworm parasites", which means discovery of a new nematocidal antibiotic, avermectin. Here, I review the many antiparasitic antibiotics and their lead compounds that have been discovered for use in human and veterinary medicine.

Nodding syndrome: bridging the gap-a scoping review protocol

INTRODUCTION

Nodding syndrome (NS) is an encephalopathy of unknown origin that affects children aged between 3 and 15 years old. Cases have been reported since the 1950 in Tanzania and South Sudan, the most heavily affected population is the Acholi community in Uganda. In response to the high incidence of the disease, the Ugandan Government has developed a management algorithm, but access to such measures in affected communities is limited. There is little funding for research on the disease, consequently, few studies have been conducted to date. Nevertheless, the number of scientific publications on NS has increased since 2013, reporting several aetiological hypotheses, management algorithms and cases of stigmatisation; however, none has obtained conclusive results.This document describes a protocol for a scoping review of NS to date aimed at obtaining a broad overview of the disease. The results will identify gaps in knowledge in order to better guide future research, intervention strategies, health policies in areas at risk and cooperation and development programmes.

METHODS AND ANALYSIS

To identify the relevant data, we will conduct a literature search using the electronic databases PubMed/Medline, Embase, Social Science Citation Index Scopus, Scientific Electronic Library Online (SciELO), Literatura Latinoamericana y del Caribe en Ciencias de la Salud (LILACS), Social Science Citation Index Expanded and The Cochrane Library. We will also include grey literature. The search strategy will be designed by a librarian.Two members of the team will work independently to identify studies for inclusion and perform data extraction. The search results will be assessed by two independent reviewers and data from the included studies will be charted and summarised in duplicate. The data will be summarised in tables and figures to present the research landscape and describe and map gaps.

ETHICS AND DISSEMINATION

Ethical approval is not required. The scoping review will adhere to the Preferred Reporting Items for Systematic Reviews andMeta-Analyses-ScR guidelines. The results will be disseminated at scientific congresses and meetings.

After 70 years of fighting an age-old scourge, onchocerciasis in Uganda, the end is in sight

Onchocerciasis causes severe itching, serious skin disease and ocular damage leading to visual impairment or permanent blindness. It is associated with hanging groin, epilepsy, Nakalanga dwarfism and, most recently, nodding disease. This disease affected communities in 17 transmission foci in 37 districts of Uganda, where about 6.7 million people are once at risk. The efforts against onchocerciasis in Uganda commenced in the late 1940s, when vector control was launched using dichlorodiphenyltrichloroethane; by 1973, Simulium damnosum had been eliminated in the Victoria focus. Success outside of the Victoria focus was short-lived due to changes in government priorities and the political upheavals of the 1970s and 1980s. With the return of political stability, annual treatment with ivermectin through mass drug administration was launched in the early 1990s. Control of the disease has been successful, but there has been failure in interrupting transmission after more than 15 years. In 2007 Uganda launched a nationwide transmission elimination policy based on twice-per-year treatment and vector control/elimination, with a goal of eliminating river blindness nationwide by 2020. By 2017, 1 157 303 people from six foci had been freed from river blindness. This is the largest population ever declared free under World Health Organization elimination guidelines, providing evidence that elimination of river blindness in Africa is possible.

Baseline characterization of epilepsy in an onchocerciasis endemic area of the Democratic Republic of Congo

Increased epilepsy prevalence is reported in onchocerciasis (OC) endemic areas and is associated with the occurrence of distinct syndromes such as nodding disease and Nakalanga syndrome. To date, a causal relationship between OC and epilepsy is still a matter of controversy. We conducted a case-control study of participants with epilepsy and age- and gender-matched presumably healthy controls to elucidate the relationships between OC and epilepsy and explore the role of inflammation and growth factors in an OC endemic area in the Democratic Republic of Congo (DRC). Eighty-two participants with epilepsy (mean age ± SD: 23.2 ± 8.7 years) and 27 controls (mean age ± SD: 22.3 ± 12.0 years) underwent snip skin biopsies to determine Onchocerca volvulus infection status. Serum concentrations of cytokines, chemokines, and growth factors were measured using a Luminex Multiplex Assay kit. Children <19 years of age underwent neurocognitive assessments using the Kaufman Assessment Battery for Children, 2^nd edition (KABC-II). Overall, epilepsy was associated with OC (OR = 4.51, z = 3.11, p = 0.0019), and children with OC were more likely to be severely stunted (OR = 11.67, z = 2.62, p = 0.0087). The relationship between epilepsy and OC was no longer significant (z = 1.27, p = 0.20) when stunting was included as a correcting covariate. Epilepsy was associated with poor KABC-II test scores, high serum levels of IL-17, and low levels of IL-1RA, IL-8, and EGF. KABC-II testing scores correlated with serum levels of IL-10, MCP-1 and HGF. Familial history of epilepsy occurred frequently. Future studies should consider cytokines and/or growth factors when assessing susceptibility to epilepsy in OC endemic areas. Additional investigations, preferentially in low-prevalence OC areas, may provide further insights into the concept, risk, and burden of river epilepsy.

Ivermectin Treatment in Patients With Onchocerciasis-Associated Epilepsy: Protocol of a Randomized Clinical Trial

BACKGROUND

Many studies have reported an association between epilepsy, nodding syndrome (NS), and onchocerciasis (river blindness). A high prevalence of epilepsy has been noted particularly in onchocerciasis hyperendemic areas where onchocerciasis is not or insufficiently controlled with mass ivermectin distribution. There is evidence that increasing the coverage of ivermectin reduces the incidence of epilepsy, and anecdotal evidence suggests a reduction in seizure frequency in onchocerciasis-associated epilepsy (OAE) patients who receive ivermectin. Finding an alternative treatment for epilepsy in these patients will have major consequences.

OBJECTIVE

The goal of the study is to assess whether ivermectin treatment decreases the frequency of seizures and leads to seizure freedom in OAE patients, including patients with NS. If we are able to demonstrate such an effect, this would strengthen the argument that onchocerciasis is causing epilepsy and therefore we should increase our efforts to eliminate onchocerciasis.

METHODS

We will conduct a randomized clinical trial in the Democratic Republic of Congo to compare seizure freedom in onchocerciasis-infested epilepsy patients who receive immediate ivermectin treatment with delayed (after 4 months) ivermectin treatment. All participants will simultaneously receive antiepilepsy drugs (AEDs) according to local guidelines for epilepsy treatment. The primary endpoint is seizure freedom defined as no seizures during the 4 month of follow-up. Secondary endpoint is significant (>50%) seizure reduction compared to baseline seizure frequency. Reduction of seizures will be compared between ivermectin and nonivermectin arms.

RESULTS

Start of enrollment is planned for August 2017, and we expect to have enrolled all 110 participants by December 2017. Results are expected in June 2018.

CONCLUSIONS

If ivermectin treatment in addition to AEDs is able to lead to seizure freedom or significantly reduces seizure frequency in OAE patients, this will have major consequences for epilepsy treatment in onchocerciasis-endemic regions. Ivermectin is donated for free and in non Loa-Loa-endemic regions has negligible side effects. Reducing the burden of epilepsy will have a major impact on quality of life and socioeconomic status of families with affected members in Africa.

TRIAL REGISTRATION

ClinicalTrials.gov NCT03052998; https://clinicaltrials.gov/ct2/show/NCT03052998 (Archived by WebCite at http://www.webcitation.org/6roFVQSG0).

Esperanza Window Traps for the collection of anthropophilic blackflies (Diptera: Simuliidae) in Uganda and Tanzania

There is an increasing need to evaluate the impact of chemotherapeutic and vector-based interventions as onchocerciasis affected countries work towards eliminating the disease. The Esperanza Window Trap (EWT) provides a possible alternative to human landing collections (HLCs) for the collection of anthropophilic blackflies, yet it is not known whether current designs will prove effective for onchocerciasis vectors throughout sub-Saharan Africa. EWTs were deployed for 41 days in northern Uganda and south eastern Tanzania where different Simulium damnosum sibling species are responsible for disease transmission. The relative efficacy of EWTs and HLCs was compared, and responses of host-seeking blackflies to odour baits, colours, and yeast-produced CO2 were investigated. Blue EWTs baited with CO2 and worn socks collected 42.3% (2,393) of the total S. damnosum s.l. catch in northern Uganda. Numbers were comparable with those collected by HLCs (32.1%, 1,817), and higher than those collected on traps baited with CO2 and BG-Lure (25.6%, 1,446), a synthetic human attractant. Traps performed less well for the collection of S. damnosum s.l. in Tanzania where HLCs (72.5%, 2,432) consistently outperformed both blue (16.8%, 563) and black (10.7%, 360) traps baited with CO2 and worn socks. HLCs (72.3%, 361) also outperformed sock-baited (6.4%, 32) and BG-Lure-baited (21.2%, 106) traps for the collection of anthropophilic Simulium bovis in northern Uganda. Contrasting blackfly distributions were observed on traps in Uganda and Tanzania, indicating differences in behaviour in each area. The success of EWT collections of S. damnosum s.l. in northern Uganda was not replicated in Tanzania, or for the collection of anthropophilic S. bovis. Further research to improve the understanding of behavioural responses of vector sibling species to traps and their attractants should be encouraged.

Ivermectin: enigmatic multifaceted 'wonder' drug continues to surprise and exceed expectations

Over the past decade, the global scientific community have begun to recognize the unmatched value of an extraordinary drug, ivermectin, that originates from a single microbe unearthed from soil in Japan. Work on ivermectin has seen its discoverer, Satoshi Ōmura, of Tokyo's prestigious Kitasato Institute, receive the 2014 Gairdner Global Health Award and the 2015 Nobel Prize in Physiology or Medicine, which he shared with a collaborating partner in the discovery and development of the drug, William Campbell of Merck & Co. Incorporated. Today, ivermectin is continuing to surprise and excite scientists, offering more and more promise to help improve global public health by treating a diverse range of diseases, with its unexpected potential as an antibacterial, antiviral and anti-cancer agent being particularly extraordinary.

Health Seeking Behaviours among Caretakers of Children with Nodding Syndrome in Pader District - Northern Uganda: A Mixed Methods Study

Background

Nodding syndrome is a neurological disorder which had affected about 3000 children with over 170 deaths in northern Uganda by 2012. With limited data on health seeking, the study aimed to assess the health seeking behavior and associated factors among caretakers of children with nodding syndrome in Pader district.

Methods

A mixed methods cross sectional study was conducted in July 2013 among 249 caretakers of children with nodding syndrome in three sub-counties of Pader. Respondents were consecutively interviewed using semi-structured questionnaires. Eleven key informants were additionally interviewed. We determined the associations of various factors with health care seeking and obtained adjusted odds ratios and 95% confidence intervals using logistic regression model. Quantitative data was analysed using Stata version 12 while qualitative data was analysed manually and quotes reported.

Results

Most caretakers, 78.3% (195/249) sought care first from a health facility, 12.9% (32/249) visited traditional healers and 8.8% (22/249) self-medicated. Of those who sought care from a health facility, 50% sought care after a month. Factors associated with improved care seeking included: Time taken to reach care 1–3 hours; adjusted odds ratio = 6.4 (95% CI = 2.96–14.03), time spent in care above five years; adjusted odds ratio = 12.0 (95% CI: 1.24–117.73) and changed care seeking place; adjusted odds ratio = 17.2 (95% CI: 3.64–81.67).

Conclusion/ Recommendation

Caretakers sought care from multiple places. One in five caretakers still sought care outside a formal health facility. Many respondents who sought care first from health facilities went late, at least one month after symptoms onset. Factors associated with health seeking included distance, duration in treatment and not having changing care provider. There is need for massive sensitization of community to enhance prompt care seeking. More research is needed to elucidate the cause, thus finding the treatment for nodding syndrome, to prevent "wandering in hope".

Prevalence of River Epilepsy in the Orientale Province in the Democratic Republic of the Congo

BACKGROUND

An increased prevalence of epilepsy has been reported in many onchocerciasis endemic areas.

OBJECTIVE

To determine the prevalence and distribution of epilepsy in an onchocerciasis endemic region in the Democratic Republic of the Congo (DRC).

DESIGN/METHODS

An epilepsy prevalence study was carried out in 2014, in two localities of the Bas-Uélé district, an onchocerciasis endemic region in the Orientale Province of the DRC. Risk factors for epilepsy were identified using a random effects logistic regression model and the distribution of epilepsy cases was investigated using the Moran's I statistic of spatial auto-correlation.

RESULTS

Among the 12,776 individuals of Dingila, 373 (2.9%) individuals with epilepsy were identified. In a house-to-house survey in Titule, 68 (2.3%) of the 2,908 people who participated in the survey were found to present episodes of epilepsy. Epilepsy showed a marked spatial pattern with clustering of cases occurring within and between adjacent households. Individual risk of epilepsy was found to be associated with living close to the nearest fast flowing river where blackflies (Diptera: Simuliidae)-the vector of Onchocerca volvulus-oviposit and breed.

CONCLUSIONS

The prevalence of epilepsy in villages in the Bas-Uélé district in the DRC was higher than in non-onchocerciasis endemic regions in Africa. Living close to a blackflies infested river was found to be a risk factor for epilepsy.

Nodding syndrome and epilepsy in onchocerciasis endemic regions: comparing preliminary observations from South Sudan and the Democratic Republic of the Congo with data from Uganda

Background

Nodding syndrome (NS) is an epilepsy disorder occurring in children in South Sudan, northern Uganda and Tanzania. The etiology of NS is unknown, but epidemiological studies demonstrate an association between NS and onchocerciasis.

Methods

Between November 2013 and July 2015 we visited onchocerciasis endemic regions in South Sudan, Uganda, and the Democratic Republic of the Congo (DRC) to assess the epilepsy situation. In South Sudan we interviewed patients and affected families, health officials, colleagues and healthcare workers, and performed a small household survey to estimate the epilepsy prevalence in the village of Mvolo, Western Equatoria State. Most information from Uganda was collected through discussions with colleagues and a review of published literature and reports. In the Bas-Uélé district of the DRC, we visited the villages of Liguga, Titule and Dingila, interviewed patients with epilepsy and family members and conducted a preliminary entomological assessment.

Results

In South Sudan there is an ongoing NS and epilepsy epidemic in the Western Equatoria state that started around 1990. A survey of 22 households in Mvolo revealed that 28 out of 168 (16.7 %) children suffered from NS or another form of epilepsy. Thirteen (59 %) households had at least one child, and nine (41 %) households at least two children with NS or another form of epilepsy. In northern Uganda, an NS and epilepsy epidemic started around 2000. The occurrence of new NS cases has been in decline since 2008 and no new NS cases were officially reported in 2013. The decline in NS cases coincided with the bi-annual distribution of ivermectin and the treatment of blackfly-breeding rivers with larvicides. In Bas-Uélé district in the DRC, epilepsy appears to be endemic with cases clustered in villages close to blackfly-infested, rapid-flowing rivers. The majority of epilepsy cases in Liguga, Dingila and Titule presented with generalized (tonic–clonic) seizures without nodding, but with mental retardation. In Titule, an epilepsy prevalence of 2.3 % was documented. The only anthropophilic species of blackfly collected in the region belonged to the Simulium damnosum complex.

Conclusion

Blackflies may play a key role in the transmission of an etiological agent that either directly or indirectly cause, not only NS, but also other forms of epilepsy in onchocerciasis endemic regions.

Financing and collaboration on research and development for nodding syndrome

Background

Nodding syndrome is a neurological disease with no known cure or treatment, impacting children aged 3–18 years old, mainly in East Africa. Children progressively develop varying degrees of cognitive impairment which may lead to severe wasting, a vegetative state and, eventually, death. Despite its 50-year existence, little is known about its cause, risk factors and prognosis. It is a disease where markets will not provide solutions because the patients are both too few and too poor, making it especially neglected. Open source innovation has been recommended as an approach to neglected disease research in order to maximize available funding through greater collaboration and openness to results. Nodding syndrome is a useful case to examine the relevance of open source innovation.

Methods

We assessed the magnitude of research related to nodding syndrome, its availability, financing and the amount of collaboration. We surveyed researchers regarding their motivations, attitudes toward open source innovation concepts and barriers to greater collaboration.

Results

Little research is occurring for nodding syndrome, but it is openly available and researchers are highly collaborative. The disease is largely unknown, which is partly attributed to WHO not classifying nodding syndrome as a neglected tropical disease and not including it in any formal programme. Impacted countries, particularly Uganda, demonstrate a strong degree of ownership through both authorship and research financing. Nodding syndrome researchers have been allocated a total of €5 million from 2013 to 2019 in grant funding. Annual financing, due to three new grants, doubled from 2014 to 2015.

Conclusions

Nodding syndrome, a disease previously ignored by the international community, is starting to receive greater attention, although financing remains modest. If infectious, a larger epidemic could take the world by surprise. Open source innovation can likely help by sharing research protocols (to avoid duplication) and early research results (to adjust to the findings of others). The existing scientists have already endorsed open source innovation, but increased financing is needed. The support of just a few high-income countries could reap a large impact.

Parasitic diseases of the central nervous system: lessons for clinicians and policy makers

Parasitic diseases of the central nervous system are associated with high mortality and morbidity, especially in resource-limited settings. The burden of these diseases is amplified as survivors are often left with neurologic sequelae affecting mobility, sensory organs, and cognitive functions, as well as seizures/epilepsy. These diseases inflict suffering by causing lifelong disabilities, reducing economic productivity, and causing social stigma. The complexity of parasitic life cycles and geographic specificities, as well as overlapping clinical manifestations in the host reflecting the diverse pathogenesis of parasites, can present diagnostic challenges. We herein provide an overview of these parasitic diseases and summarize clinical aspects, diagnosis, therapeutic strategies and recent milestones, and aspects related to prevention and control.

Infections, inflammation and epilepsy

Epilepsy is the tendency to have unprovoked epileptic seizures. Anything causing structural or functional derangement of brain physiology may lead to seizures, and different conditions may express themselves solely by recurrent seizures and thus be labelled "epilepsy." Worldwide, epilepsy is the most common serious neurological condition. The range of risk factors for the development of epilepsy varies with age and geographic location. Congenital, developmental and genetic conditions are mostly associated with the development of epilepsy in childhood, adolescence and early adulthood. Head trauma, infections of the central nervous system (CNS) and tumours may occur at any age and may lead to the development of epilepsy. Infections of the CNS are a major risk factor for epilepsy. The reported risk of unprovoked seizures in population-based cohorts of survivors of CNS infections from developed countries is between 6.8 and 8.3 %, and is much higher in resource-poor countries. In this review, the various viral, bacterial, fungal and parasitic infectious diseases of the CNS which result in seizures and epilepsy are discussed. The pathogenesis of epilepsy due to brain infections, as well as the role of experimental models to study mechanisms of epileptogenesis induced by infectious agents, is reviewed. The sterile (non-infectious) inflammatory response that occurs following brain insults is also discussed, as well as its overlap with inflammation due to infections, and the potential role in epileptogenesis. Furthermore, autoimmune encephalitis as a cause of seizures is reviewed. Potential strategies to prevent epilepsy resulting from brain infections and non-infectious inflammation are also considered.

Nodding syndrome, western Uganda, 1994

Nodding syndrome (NS) is a poorly understood condition, which was delineated in 2008 as a new epilepsy syndrome. So far, confirmed cases of NS have been observed in three circumscribed African areas: southern Tanzania, southern Sudan, and northern Uganda. Case-control studies have provided evidence of an association between NS and infection with Onchocerca volvulus, but the causation of NS is still not fully clarified. We report a case of a 15-year old boy with head nodding seizures and other characteristic features of NS from an onchocerciasis endemic area in western Uganda, with no contiguity to the hitherto known areas. We suggest that the existence of NS should be systematically investigated in other areas.