Nodding syndrome (NS) and Onchocerca Volvulus (OV) in Northern Uganda

Lagoro, David Kitara; Arony, Denis Anywar

doi:10.11604/pamj.2017.28.1.13554

Cited by 10 publications

(4 citation statements)

References 8 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…A suspected case of NS was reportedly seen in India [ 73 ], but the clinical presentation was substantially marred by preexisting neurological conditions, thus making the diagnosis of NS very unlikely. While other infectious, nutritional, or environmental causes have been suggested for the NS [ 74 , 75 ], the most significant association was consistently found with O . volvulus infection [ 76 ].…”

Section: Resultsmentioning

confidence: 99%

Onchocerca volvulus and epilepsy: A comprehensive review using the Bradford Hill criteria for causation

et al. 2021

View full text Add to dashboard Cite

Background The possibility that onchocerciasis may cause epilepsy has been suggested for a long time, but thus far, an etiological link has not been universally accepted. The objective of this review is to critically appraise the relationship between Onchocerca volvulus and epilepsy and subsequently apply the Bradford Hill criteria to further evaluate the likelihood of a causal association. Methods PubMed and gray literature published until September 15, 2020, were searched and findings from original research were synthesized. Adherence to the 9 Bradford Hill criteria in the context of onchocerciasis and epilepsy was determined to assess whether the criteria are met to strengthen the evidence base for a causal link between infection with O. volvulus and epilepsy, including the nodding syndrome. Results Onchocerciasis as a risk factor for epilepsy meets the following Bradford Hill criteria for causality: strength of the association, consistency, temporality, and biological gradient. There is weaker evidence supporting causality based on the specificity, plausibility, coherence, and analogy criteria. There is little experimental evidence. Considering the Bradford Hill criteria, available data suggest that under certain conditions (high microfilarial load, timing of infection, and perhaps genetic predisposition), onchocerciasis is likely to cause epilepsy including nodding and Nakalanga syndromes. Conclusion Applying the Bradford Hill criteria suggests consistent epidemiological evidence that O. volvulus infection is a trigger of epilepsy. However, the pathophysiological mechanisms responsible for seizure induction still need to be elucidated.

show abstract

Section: Resultsmentioning

confidence: 99%

Onchocerca volvulus and epilepsy: A comprehensive review using the Bradford Hill criteria for causation

et al. 2021

View full text Add to dashboard Cite

show abstract

“…The epidemiological association between OV and NS has been questioned. 81 OV occurs in 34 countries in Africa, the Middle East, South and Central America, with an estimated 17.7 million people affected. 82 In contrast, there have only been several thousand cases of NS in restricted parts of Africa.…”

Section: Discussionmentioning

confidence: 99%

Aetiologies and therapies of nodding syndrome: a systematic review and meta-analysis

Stacey

Woodhouse²,

Welburn³

et al. 2019

Journal of Global Health Reports

View full text Add to dashboard Cite

Nodding syndrome (NS) is a childhood epileptic disorder of unknown aetiology confined to parts of South Sudan, Uganda and the United Republic of Tanzania. Patients suffer from atonic seizures that result in characteristic head nodding, and may develop other neurological, endocrinological and psychiatric manifestations. The objective of this study was to adopt a non-judgemental approach to review the hypothesised aetiologies and therapeutic options available for NS. To explore the reported association between NS and Onchocerca volvulus (OV) a meta-analysis of the prevalence of OV among NS cases and controls was performed. Methods MethodsSystematic searching of five electronic databases yielded 26 articles that addressed potential aetiologies of NS and 12 that explored the treatment of NS. R Results esultsNine articles contained data about the prevalence of OV in NS cases that was suitable for inclusion in the meta-analysis. Four broad aetiological themes were identified. 1) Nutritional associations included biomarkers of malnutrition and conflicting reports regarding the consumption of some foodstuffs. 2) Regional conflict and the associated psychological trauma have led to consideration of psychiatric aetiologies. 3) There is a strong epidemiological association between NS and Onchocerca volvulus. The meta-analysis in this study revealed that 68.0% (95% confidence interval (CI)=45.2-87.0) of 416 NS patients were OV+, compared to 46.6% (95% CI=16.4-78.1) of 321 controls. Heterogeneity among both cases (I 2 =95.5%, 95% CI=93.3-97.0) and controls (I 2 =97.1%, 95% CI=95.5-98.2) was high. The difference of 21.4% in OV prevalence between the pooled populations was significant (P<0.0001). It is thought that NS represents a form of onchocerciasis-associated epilepsy, however there are also reported associations with Mansonella pestans and measles virus. 4) Autoantibodies against leiomodin-1 and the voltage-gated potassium channel have been associated with NS. Molecular mimicry between leiomodin-1 and O. volvulus tropomyosin is a recently suggested aetiology. Without a clear aetiology treatment is symptomatic and patients have been shown to improve with a combination of anti-epileptic medication and supportive therapy. C Conclusions onclusionsThe aetiology of NS remains unclear. The leading theory is that NS represents a form of onchocerciasis-associated epilepsy secondary to autoimmunity driven by molecular mimicry. Alternatively, it has been suggested that NS may represent a post-infectious sequelae of measles virus infection. However, each theory currently leaves some questions unanswered. It remains important to understand the aetiology of NS to better prevent or treat future outbreaks.Nodding syndrome (NS) is a neurological condition of unknown aetiology confined to parts of the United Republic of Tanzania (URT), South Sudan and Uganda. The characteristic head nodding that gives the syndrome its name was

show abstract

“…The burden places upon affected communities are multifaceted; ranging from physical and mental health decline of an individual child to increasing health disparities of the entire community. It should be considered a critical and pervasive threat to human security in the affected communities of Northern Uganda because it exacerbates vulnerability to socioeconomic activities thereby results in extreme poverty to families [5].…”

Section: Introductionmentioning

confidence: 99%

Spatiotemporal Analysis of Nodding Syndrome in Northern Uganda 1990-2014

Ongaya

Aturinde

Farnaghi

et al. 2020

Health

View full text Add to dashboard Cite

The emergence of nodding syndrome (NS) in Northern Uganda has generated controversial views with respect to patterns, natural history, and aetiology of the disease which is yet unknown. This study explored spatial patterns of NS using spatial-temporal methods to establish its clustering patterns across both space and time. Village and year of NS onset for individual patients between the years 1990 and 2014 were entered as input for spatial and temporal analysis in the 6 districts in northern Uganda where it is prevalent. Our temporal results showed that NS onset started before the population was moved in Internally Displaced People's (IDPs) camps. It also shows that NS continued to be reported during the IDPs and after people had left the IDPs. Our spatial and spatiotemporal analysis showed that two periods had persistent NS clusters. These were 2000-2004 and 2010-2014, coinciding with the period when the population was in the IDP camps and when the population was already out of the camps, respectively. Our conclusion is that the view of associating NS outbreak with living conditions in IDP camps is thus coincidental. We, therefore, contend that the actual aetiological factor of NS is still at large.

show abstract

Nodding syndrome (NS) and Onchocerca Volvulus (OV) in Northern Uganda

Cited by 10 publications

References 8 publications

Onchocerca volvulus and epilepsy: A comprehensive review using the Bradford Hill criteria for causation

Onchocerca volvulus and epilepsy: A comprehensive review using the Bradford Hill criteria for causation

Aetiologies and therapies of nodding syndrome: a systematic review and meta-analysis

Spatiotemporal Analysis of Nodding Syndrome in Northern Uganda 1990-2014

Contact Info

Product

Resources

About