Risk mapping and environmental delineation of filariasis transmission hotspots in Central Africa

Onchocerciasis (river blindness) is a neglected tropical disease (NTD) targeted for global elimination. The disease is caused by the parasite Onchocerca volvulus and transmitted by black flies (Simulium) that breed in rivers and streams. The highest burden occurs in sub-Saharan Africa and in communities near rivers. The National NTD programmes have been implementing mass drug administration (MDA) of ivermectin to interrupt transmission in meso- and hyper-endemic areas. This MDA strategy has been recently extended to hypo-endemic areas as part of the elimination goal and raised two main challenges. First, hypo-endemic areas are geographically vast and the focal areas of transmission or ‘micro-hotspots’ are not well-defined making populations at risk difficult to identify and treat with effective coverage.  Second, the distribution of high prevalence loiasis (eye worm) in forested areas, increases the risk of severe adverse events (SAEs) associated with ivermectin, resulting in the need for alternative intervention strategies, which may include vector control. 

There is a need to better define the distribution of micro-hotspots in hypo-endemic onchocerciasis areas and the extent to which they geographically overlap with loiasis hotspots. The use environmental data to delineate riverine and forest risk factors associated with the onchocerciasis Simulium and loiasis Chrysops vector habitats may help to delineate risk areas and target interventions. This PhD project will address these challenges through a combination a desk-based and field-based work by i) identifying and mapping hotspots using onchocerciasis and loiasis prevalence and vector data available in open source databases ii) developing risk maps and spatial ecological maps and models to characterize hotspots using high resolution satellite imagery and environmental data, and ii) micro-mapping ecological characteristics of prevalence distributions and vector habitats within hotspots using community participatory mapping and innovative mHealth tools.

Where does the project lie on the Translational Pathway?

T2 Human/Clinical Research + T3 Evidence into Practice

Expected Outputs

Authorship on major articles

Training Opportunities

 

GIS mapping methods

Satellite remote sensing data processing

Spatial ecological modelling

 

Skills Required

 

Good quantitative skills with an interest in mapping, environment, and climate.

 

Key Publications associated with this project

Badia-Rius X, Betts H, Molyneux DH, Kelly-Hope LA. Environmental factors associated with the distribution of Loa loa vectors Chrysops spp. in Central and West Africa: seeing the forest for the trees. Parasit Vectors. 2019 Feb 6;12(1):72.

Kelly-Hope LA, Blundell HJ, Macfarlane CL, Molyneux DH. Innovative Surveillance Strategies to Support the Elimination of Filariasis in Africa. Trends Parasitol. 2018 Aug;34(8):694-711.

Kelly-Hope LA, Unnasch TR, Stanton MC, Molyneux DH. Hypo-endemic onchocerciasis hotspots: defining areas of high risk through micro-mapping and environmental delineation. Infect Dis Poverty. 2015 16;4:36.

Brant TA, Okorie PN, Ogunmola O, Ojeyode NB, Fatunade SB, Davies E, Saka Y, Stanton M, Molyneux DH, Russell Stothard J, Kelly-Hope LA. Integrated risk mapping and landscape characterisation of lymphatic filariasis and loiasis in South West Nigeria Parasite Epidemiol Control. 2017 Dec 28;3(1):21-35.

Stanton MC, Molyneux DH, Kyelem D, Bougma RW, Koudou BG, Kelly-Hope LA.

Baseline drivers of lymphatic filariasis in Burkina Faso. Geospat Health. 2013 Nov;8(1):159-73.

LSTM Themes and Topics – Key Words

Neglected Tropical Diseases