TY - JOUR

T1 - Understanding the spatial distribution of trichiasis and its association with trachomatous inflammation—follicular

AU - Flueckiger, Rebecca Mann

AU - Giorgi, Emanuele

AU - Cano, Jorge

AU - Abdala, Mariamo

AU - Amiel, Olga Nelson

AU - Baayenda, Gilbert

AU - Bakhtiari, Ana

AU - Batcho, Wilfrid

AU - Bennawi, Kamal Hashim

AU - Dejene, Michael

AU - Elshafie, Balgesa Elkheir

AU - Elvis, Aba Ange

AU - Francois, Missamou

AU - Goepogui, Andre

AU - Kalua, Khumbo

AU - Kebede, Biruck

AU - Kiflu, Genet

AU - Masika, Michael P.

AU - Massangaie, Marilia

AU - Mpyet, Caleb

AU - Ndjemba, Jean

AU - Ngondi, Jeremiah M.

AU - Olobio, Nicholas

AU - Turyaguma, Patrick

AU - Willis, Rebecca

AU - Yeo, Souleymane

AU - Solomon, Anthony W.

AU - Pullan, Rachel L.

PY - 2019/4/30

Y1 - 2019/4/30

N2 - BackgroundWhilst previous work has identified clustering of the active trachoma sign “trachomatous inflammation—follicular” (TF), there is limited understanding of the spatial structure of trachomatous trichiasis (TT), the rarer, end-stage, blinding form of disease. Here we use community-level TF prevalence, information on access to water and sanitation, and large-scale environmental and socio-economic indicators to model the spatial variation in community-level TT prevalence in Benin, Cote d’Ivoire, DRC, Guinea, Ethiopia, Malawi, Mozambique, Nigeria, Sudan and Uganda.MethodsWe fit binomial mixed models, with community-level random effects, separately for each country. In countries where spatial correlation was detected through a semi-variogram diagnostic check we then fitted a geostatistical model to the TT prevalence data including TF prevalence as an explanatory variable.ResultsThe estimated regression relationship between community-level TF and TT was significant in eight countries. We estimate that a 10% increase in community-level TF prevalence leads to an increase in the odds for TT ranging from 20 to 86% when accounting for additional covariates.ConclusionWe find evidence of an association between TF and TT in some parts of Africa. However, our results also suggest the presence of additional, country-specific, spatial risk factors which modulate the variation in TT risk.

AB - BackgroundWhilst previous work has identified clustering of the active trachoma sign “trachomatous inflammation—follicular” (TF), there is limited understanding of the spatial structure of trachomatous trichiasis (TT), the rarer, end-stage, blinding form of disease. Here we use community-level TF prevalence, information on access to water and sanitation, and large-scale environmental and socio-economic indicators to model the spatial variation in community-level TT prevalence in Benin, Cote d’Ivoire, DRC, Guinea, Ethiopia, Malawi, Mozambique, Nigeria, Sudan and Uganda.MethodsWe fit binomial mixed models, with community-level random effects, separately for each country. In countries where spatial correlation was detected through a semi-variogram diagnostic check we then fitted a geostatistical model to the TT prevalence data including TF prevalence as an explanatory variable.ResultsThe estimated regression relationship between community-level TF and TT was significant in eight countries. We estimate that a 10% increase in community-level TF prevalence leads to an increase in the odds for TT ranging from 20 to 86% when accounting for additional covariates.ConclusionWe find evidence of an association between TF and TT in some parts of Africa. However, our results also suggest the presence of additional, country-specific, spatial risk factors which modulate the variation in TT risk.

KW - Trachoma

KW - Trichiasis

KW - Blindness

KW - Visual impairment

KW - Neglected tropical disease

KW - Epidemiology

KW - Global trachoma mapping project

U2 - 10.1186/s12879-019-3935-1

DO - 10.1186/s12879-019-3935-1

M3 - Journal article

VL - 19

JO - BMC Infectious Diseases

JF - BMC Infectious Diseases

SN - 1471-2334

M1 - 364

ER -