bioRxiv Science⌕ Search
Home/Archive/bioRxiv

bioRxiv · 10.1101/577247

Onchocerciasis-associated epilepsy in the Democratic Republic of Congo: Clinical description and relationship with microfilarial density

Siewe Fodjo, J. N.·Mandro, M. N.·Mukendi, D.·Tepage, F.·Menon, S.·Nakato, S.·Francoise, N.·Abhafule, G.·Wonya'rossi, D.·Anyolito, A.·Lokonda, R.·Hotterbeekx, A.·Colebunders, R.
View original source ↗Export metadata ↓

Abstract

Background: High epilepsy prevalence and incidence were observed in onchocerciasis-endemic villages in the Democratic Republic of Congo (DRC). We sought to investigate the clinical characteristics of onchocerciasis-associated epilepsy (OAE), and the relationship with microfilarial density. Methods: In October 2017, ivermectin-naive persons with epilepsy (PWE) were recruited from onchocerciasis-endemic areas in the Logo health zone in the DRC. Additional PWE were enrolled in the Aketi health zone, where ivermectin had been distributed annually for 14 years. Past medical history, clinical characteristics and skin snips for Onchocerca volvulus detection were obtained from participants. Bivariate and multivariable analyses were used to investigate associations with microfilarial density. Results: Of the 420 PWE in the Logo health zone, 392 were skin snipped (36.5% positive). Generalized motor seizures were most frequent (392 PWE, 93.3%), and nodding seizures were reported in 32 (7.6%) participants. Twelve PWE (3.1%) presented Nakalanga features. More skin snip-positive participants reported a family history of epilepsy (p=0.027). Eighty-one onchocerciasis-infected PWE were recruited in the Aketi health zone. Positive correlations between seizure frequency and microfilarial density were observed in Logo (Spearman-rho=0.181; p=0.0003) and Aketi (Spearman-rho=0.228; p=0.046). In the multivariable analysis which adjusted for age, gender and previous anti-epileptic drug use, factors associated with high seizure frequency included: high microfilarial density (RR=1.004, 95% CI: 1.002-1.007; p<0.001), history of nodding seizures (RR=3.852, 95% CI: 2.926-5.082; p<0.001) and shorter duration of epilepsy (RR=0.948, 95% CI: 0.928-0.968; p<0.001). In Aketi, previous ivermectin use was associated with reduced seizures (RR=0.69, 95% CI: 0.58-0.83; p<0.001). Conclusion: In onchocerciasis-endemic regions in the DRC, a wide spectrum of seizures was observed. Nodding seizures, Nakalanga features, and a positive association between microfilarial density and seizures suggest a high OAE prevalence in the study villages, requiring a double management strategy: treatment with anti-epileptic drugs and stronger onchocerciasis elimination programs.

Source connections

Explore related subjects

neurosciencePreprint

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Siewe Fodjo, J. N., Mandro, M. N., Mukendi, D., Tepage, F., Menon, S., Nakato, S., Francoise, N., Abhafule, G., Wonya'rossi, D., Anyolito, A., Lokonda, R., Hotterbeekx, A., Colebunders, R.. 2019-03-13. Onchocerciasis-associated epilepsy in the Democratic Republic of Congo: Clinical description and relationship with microfilarial density. https://doi.org/10.1101/577247

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related preprints

bioRxiv2026

Novel Tau Interaction Partners as Potential Biomarkers and Therapeutic Targets in Neurodegenerative Diseases

Alzheimers disease is a progressive neurodegenerative disorder leading to cognitive decline and ultimately death. One of the main hallmarks of this disease is the accumulation of pathological tau protein into neurofibrillary tangles. To better understand these pathological mechanisms, it is essential to characterize the tau protein interactome in health and disease. In this study, we performed a yeast two-hybrid screening using a human brain cDNA library, from which we identified 15 novel tau-interacting proteins that bind to full-length human tau, or its fragments: the N-terminus, microtubule-binding domain, or C-terminus. We subsequently validated these novel interactions using in vitro co-immunoprecipitation and colocalization assays with both physiological and pathological tau isoforms. Furthermore, their interactions with the human tau protein were analyzed using surface plasmon resonance. Finally, an in silico interactome analysis of these newly discovered tau-binding partners revealed several additional interactors that can link them to downstream processes critical to neurodegenerative pathways Our findings offer fresh insights into tau biology and highlight novel targets for therapeutic intervention and biomarker development.

neuroscience↗
bioRxiv2026

Early visual cortex is not functionally necessary for temporal attention: A TMS study

Temporal attention enhances the selective processing of information at a specific point in time and improves perception. Previous neuroimaging studies investigating its neural mechanisms have either conflated temporal attention with temporal expectation or provided correlational evidence. Thus, whether early visual cortex is functionally necessary for temporal attention remains unknown. Here, we combined psychophysics with transcranial magnetic stimulation (TMS) to examine whether V1/V2 are functionally necessary and play a causal role in temporal attention. Observers performed an orientation-discrimination task in which two consecutive stimuli, T1 and T2, were presented in the periphery, preceded by a precue providing either valid or neutral temporal information. Double-pulse TMS was delivered under four conditions: at T1 (T1-TMS), at T2 (T2-TMS), at both T1 and T2 (both-TMS), or not at all (none-TMS), to assess its effects on temporal attention and the efficacy of the stimulation was verified by pupil size analysis. Behavioral results revealed robust temporal attention benefits on d', reaction time, and the Balanced Integration Score (BIS) across all four TMS conditions, indicating that the benefits of temporal attention were unaffected by occipital TMS. Furthermore, pupil dilation was largest in the both-TMS condition, followed by the T1-TMS and T2-TMS conditions, and smallest in the none-TMS condition, providing physiological verification of the stimulation protocol. Together, these findings reveal the first causal evidence that the early visual cortex is not functionally necessary for endogenous temporal attention.

neuroscience↗
bioRxiv2026

Disentanglement of persistent and dynamic neural substrates of working memory

Competing theories of working memory have alternatively emphasized the importance of persistent and dynamic substrates of this cognitive function. Here, we directly tested these theories by computationally isolating the contributions of persistent and dynamic activity to working memory. We analyzed neuronal population activity recordings in macaques doing match/non-match working memory tasks. We first extracted signatures of persistent and dynamic activity through cue-specific temporal means, temporal principal components, and correlations of activity patterns across task epochs. We then generated synthetic data constrained by these signatures, and decoded cue stimuli from these data, separately from persistent and non-persistent neurons. We found that high decoding performance arose from a nuanced interplay of persistent and dynamic activity. Specifically, we could decode stimuli at empirical or above-chance levels across all tasks only from persistent neurons, but only after constraining correlations of activity patterns across epochs. In this way, we showed distinct roles for persistent and dynamic neuronal activity that help to unify two competing theories of working memory. More broadly, we also advanced computational controlled experiments as a principled framework for adjudicating between competing models of neuronal population activity.

neuroscience↗