Seasonal and inter-annual drivers of yellow fever transmission in South America
File(s)
Published version
Author(s)
Hamlet, Arran
Gaythorpe, Katy AM
Garske, Tini
Ferguson, Neil M
Type
Journal Article
Abstract
In the last 20 years yellow fever (YF) has seen dramatic changes to its incidence and geographic extent, with the largest outbreaks in South America since 1940 occurring in the previously unaffected South-East Atlantic coast of Brazil in 2016–2019. While habitat fragmentation and land-cover have previously been implicated in zoonotic disease, their role in YF has not yet been examined. We examined the extent to which vegetation, land-cover, climate and host population predicted the numbers of months a location reported YF per year and by each month over the time-period. Two sets of models were assessed, one looking at interannual differences over the study period (2003–2016), and a seasonal model looking at intra-annual differences by month, averaging over the years of the study period. Each was fit using hierarchical negative-binomial regression in an exhaustive model fitting process. Within each set, the best performing models, as measured by the Akaike Information Criterion (AIC), were combined to create ensemble models to describe interannual and seasonal variation in YF. The models reproduced the spatiotemporal heterogeneities in YF transmission with coefficient of determination (R2) values of 0.43 (95% CI 0.41–0.45) for the interannual model and 0.66 (95% CI 0.64–0.67) for the seasonal model. For the interannual model, EVI, land-cover and vegetation heterogeneity were the primary contributors to the variance explained by the model, and for the seasonal model, EVI, day temperature and rainfall amplitude. Our models explain much of the spatiotemporal variation in YF in South America, both seasonally and across the period 2003–2016. Vegetation type (EVI), heterogeneity in vegetation (perhaps a proxy for habitat fragmentation) and land cover explain much of the trends in YF transmission seen. These findings may help understand the recent expansions of the YF endemic zone, as well as to the highly seasonal nature of YF.
Editor(s)
Azman, Andrew S
Date Issued
2021-01-11
Date Acceptance
2020-11-11
Citation
PLoS Neglected Tropical Diseases, 2021, 15
ISSN
1935-2727
Publisher
Public Library of Science (PLoS)
Journal / Book Title
PLoS Neglected Tropical Diseases
Volume
15
Copyright Statement
© 2021 Hamlet 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
License URL
Identifier
https://www.ncbi.nlm.nih.gov/pubmed/33428623
PII: PNTD-D-19-01798
Subjects
BRAZIL
CLIMATE-CHANGE
DISEASE
DYNAMICS
Infectious Diseases
Life Sciences & Biomedicine
OUTBREAK
Parasitology
POPULATION
RECOMMENDATIONS
RISK
Science & Technology
Tropical Medicine
VECTOR
VIRUS
Publication Status
Published
Coverage Spatial
United States
Article Number
e0008974
Date Publish Online
2021-01-11