Serotonin Levels in the Serum of Persons with Onchocerciasis-Associated Epilepsy: A Case-Control Study

• Main Authors: Melissa Krizia Vieri, An Hotterbeekx, Michel Mandro, Joseph Nelson Siewe Fodjo, Alfred Dusabimana, Francoise Nyisi, Deby Mukendi, Joe Gwatsvaira, Samir Kumar-Singh, Robert Colebunders
• Format: Article
• Language: English
• Published: MDPI AG 2021-06-01
• Series: Pathogens
• Subjects: epilepsy; nodding syndrome; onchocerciasis; <i>Onchocerca volvulus</i>; serotonin; pathogenesis
• Online Access: https://www.mdpi.com/2076-0817/10/6/720

Onchocerciasis-associated epilepsy (OAE) is a devastating childhood disorder occurring in areas with high <i>Onchocerca volvulus</i> transmission. Despite epidemiological evidence showing the association between <i>O. volvulus</i> and epilepsy, the underlying mechanism remains unknown. Since high levels of serotonin are known to induce seizures, we investigated serotonin levels in persons with OAE and controls selected from the Democratic Republic of Congo. Serum serotonin levels were determined by ELISA in 19 persons with OAE, 32 persons with epilepsy without <i>O. volvulus</i> infection, 18 with <i>O. volvulus</i> infection but without epilepsy, and 35 with neither <i>O. volvulus</i> infection nor epilepsy. <i>O. volvulus</i> infection was diagnosed by skin snip testing and/or OV16 antibody detection. Serum serotonin levels were significantly decreased in persons with OAE compared to persons with <i>O. volvulus</i> infection and no epilepsy. In conclusion, an increased serotonin level is unable to explain the pathogenesis of OAE. Other hypotheses to identify the causal mechanism of OAE will need to be investigated.