Assessing the Potential Risk Factors Associated with Nodding Syndrome in Northern Uganda

Location: Northern Uganda

Alumni: Brooke Miers

Faculty: Lacey Ahern

Nodding Syndrome (NS) is a neurological disease of unknown etiology primarily affecting children and young adults in a few districts in Northern Uganda. NS has been classified as a form of atonic epilepsy and symptoms include uncontrolled head nodding, stunted growth and intellectual disability. Not only does NS cause debilitating symptoms in those affected, but also provokes stigma and unrest throughout affected communities. Although the etiology is unknown, some studies show an association between NS and onchocerciasis, and propose that the vector carrying the causative agent of NS is the Simulium spp. black flies. This project aimed to support the hypothesis of Simulium spp. as the vector for NS by exploring the prevalence of these black flies in areas affected by NS, and through spatial mapping of potential risk factors. The two objectives of this project were: 1) to better understand and spatially map possible NS risk factors through household assessments and surveys, and 2) to determine density and distribution through collection and identification of Simulium spp. black flies. Demographic and characteristic data was collected from area households both with and without reported NS cases. Black flies were collected using the Esperanza Window Trap and identified to genus. The Simulium spp. densities, data obtained from the households, and remotely sensed data were mapped using QGIS in order to visualize possible patterns and associations of risk factors of the disease. Maxent was also used to create a map to visualize predicted vector niches according to ecological variables. Associations between NS and onchocerciasis were found, supporting the link between NS and black flies as vectors. Also, we found age range of NS case onset possibly broader than previously reported. It is our hope that this research will increase knowledge on this disease and its hypothesized vector.

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