Publications by authors named "Elex Hill"

2 Publications

  • Page 1 of 1

Predicting the environmental suitability for onchocerciasis in Africa as an aid to elimination planning.

PLoS Negl Trop Dis 2021 Jul 28;15(7):e0008824. Epub 2021 Jul 28.

Department of Health Policy Planning and Management, University of Health and Allied Sciences, Ho, Ghana.

Recent evidence suggests that, in some foci, elimination of onchocerciasis from Africa may be feasible with mass drug administration (MDA) of ivermectin. To achieve continental elimination of transmission, mapping surveys will need to be conducted across all implementation units (IUs) for which endemicity status is currently unknown. Using boosted regression tree models with optimised hyperparameter selection, we estimated environmental suitability for onchocerciasis at the 5 × 5-km resolution across Africa. In order to classify IUs that include locations that are environmentally suitable, we used receiver operating characteristic (ROC) analysis to identify an optimal threshold for suitability concordant with locations where onchocerciasis has been previously detected. This threshold value was then used to classify IUs (more suitable or less suitable) based on the location within the IU with the largest mean prediction. Mean estimates of environmental suitability suggest large areas across West and Central Africa, as well as focal areas of East Africa, are suitable for onchocerciasis transmission, consistent with the presence of current control and elimination of transmission efforts. The ROC analysis identified a mean environmental suitability index of 0·71 as a threshold to classify based on the location with the largest mean prediction within the IU. Of the IUs considered for mapping surveys, 50·2% exceed this threshold for suitability in at least one 5 × 5-km location. The formidable scale of data collection required to map onchocerciasis endemicity across the African continent presents an opportunity to use spatial data to identify areas likely to be suitable for onchocerciasis transmission. National onchocerciasis elimination programmes may wish to consider prioritising these IUs for mapping surveys as human resources, laboratory capacity, and programmatic schedules may constrain survey implementation, and possibly delaying MDA initiation in areas that would ultimately qualify.
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http://dx.doi.org/10.1371/journal.pntd.0008824DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8318275PMC
July 2021

A database of geopositioned onchocerciasis prevalence data.

Sci Data 2019 May 22;6(1):67. Epub 2019 May 22.

Institute for Health Metrics and Evaluation, University of Washington, 2301 5th Ave., Seattle, WA, United States.

Onchocerciasis is a neglected tropical disease with numerous symptoms and side effects, and when left untreated can lead to permanent blindness or skin disease. This database is an attempt to combine onchocerciasis prevalence data from peer-reviewed publications into a single open-source dataset. The process followed to extract and format the information has been detailed in this paper. A total of 14,043 unique location, diagnostic, age and sex-specific records from 1975-2017 have been collected, organized and marked for collapse where a single geo-position is shared between multiple records. The locations vary from single villages up to smaller administrative units and onchocerciasis control program-defined foci. This resulting database can be used to by the global health community to advance understanding of the distribution of onchocerciasis infection and disease.
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http://dx.doi.org/10.1038/s41597-019-0079-5DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6531454PMC
May 2019
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