TY - JOUR
T1 - Topography and environmental deficiencies are associated with chikungunya virus exposure in urban informal settlements in Salvador, Brazil
AU - Travis, Catherine Tamera
AU - Argibay, Hernán D.
AU - Pellizzaro, Maysa
AU - de Oliveira, Daiana
AU - Santana, Roberta
AU - Palma, Fabiana Almerinda G.
AU - Lustosa, Ricardo
AU - Santana, Juliet Oliveira
AU - Souza, Fábio Neves
AU - Alzate López, Yeimi Alexandra
AU - Reis, Mitermayer G.
AU - Ko, Albert I.
AU - Diggle, Peter J.
AU - Ribeiro, Guilherme S.
AU - Begon, Michael
AU - Costa, Federico
AU - Khalil, Hussein
AU - Eyre, Max T.
N1 - Publisher Copyright:
Copyright: © 2025 Travis et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
PY - 2025/9/5
Y1 - 2025/9/5
N2 - BACKGROUND: Chikungunya virus (CHIKV) is an arbovirus with a significant global public health burden. Delineating the specific contributions of individual behaviour, household, natural and built environment to CHIKV transmission is important for reducing risk in urban informal settlements but challenging due to their heterogeneous environments. The aim of this study was to quantify variation in CHIKV seroprevalence between and within four urban communities in a large Brazilian city, and identify the respective contributions of individual, household, and environmental factors for seropositivity. METHODOLOGY/PRINCIPAL FINDINGS: A cross-sectional serological survey was conducted in four low-income communities in Salvador, Brazil in 2018 to collect individual, household and CHIKV IgG serology data for 1318 participants. Fine-scale community mapping of high-risk environmental features and remotely sensed environmental data were used to improve characterisation of the microenvironment close to the household. We categorised risk factors into three domains - individual, household, and environmental and used binomial mixed-effect models to identify associations with CHIKV seropositivity. CHIKV seroprevalence was 4.8%, 6.1% and 4.3% in three communities and 22.6% in one community which had a distinct topographical profile. The only individual domain variable associated with seropositivity was male sex (OR 1.67, 95% CI 1.11 - 2.36), but several environmental variables, including living in a house on a steep hillside, at medium to high elevations, and with surface water nearby, were associated with higher seropositivity. CONCLUSIONS/SIGNIFICANCE: Our findings indicate that CHIKV exposure risk can vary significantly between nearby communities and at fine spatial scales within communities and is likely to be driven more strongly by the availability of mosquito breeding sites rather than individual exposure patterns. They suggest that environmental deficiencies and topography, a proxy for several environmental processes including the degree of urbanisation and flooding risk, may play an important role in driving risk at both of these scales.
AB - BACKGROUND: Chikungunya virus (CHIKV) is an arbovirus with a significant global public health burden. Delineating the specific contributions of individual behaviour, household, natural and built environment to CHIKV transmission is important for reducing risk in urban informal settlements but challenging due to their heterogeneous environments. The aim of this study was to quantify variation in CHIKV seroprevalence between and within four urban communities in a large Brazilian city, and identify the respective contributions of individual, household, and environmental factors for seropositivity. METHODOLOGY/PRINCIPAL FINDINGS: A cross-sectional serological survey was conducted in four low-income communities in Salvador, Brazil in 2018 to collect individual, household and CHIKV IgG serology data for 1318 participants. Fine-scale community mapping of high-risk environmental features and remotely sensed environmental data were used to improve characterisation of the microenvironment close to the household. We categorised risk factors into three domains - individual, household, and environmental and used binomial mixed-effect models to identify associations with CHIKV seropositivity. CHIKV seroprevalence was 4.8%, 6.1% and 4.3% in three communities and 22.6% in one community which had a distinct topographical profile. The only individual domain variable associated with seropositivity was male sex (OR 1.67, 95% CI 1.11 - 2.36), but several environmental variables, including living in a house on a steep hillside, at medium to high elevations, and with surface water nearby, were associated with higher seropositivity. CONCLUSIONS/SIGNIFICANCE: Our findings indicate that CHIKV exposure risk can vary significantly between nearby communities and at fine spatial scales within communities and is likely to be driven more strongly by the availability of mosquito breeding sites rather than individual exposure patterns. They suggest that environmental deficiencies and topography, a proxy for several environmental processes including the degree of urbanisation and flooding risk, may play an important role in driving risk at both of these scales.
U2 - 10.1371/journal.pntd.0013477
DO - 10.1371/journal.pntd.0013477
M3 - Article
C2 - 40911655
AN - SCOPUS:105016508203
SN - 1935-2727
VL - 19
JO - PLoS Neglected Tropical Diseases
JF - PLoS Neglected Tropical Diseases
IS - 9
M1 - e0013477
ER -
