Goats from the Zagros Mountains may represent the earliest examples of goat herding.
Image credit: The Central Zagros Project.
Edited by Alan Hastings, University of California, Davis, CA, and approved March 30, 2017 (received for review December 8, 2016)
Significance
Mathematical and computational modeling approaches can be essential in providing quantitative scenarios of disease spreading, as well as projecting the impact in the population. Here we analyze the spatial and temporal dynamics of the Zika virus epidemic in the Americas with a microsimulation approach informed by high-definition demographic, mobility, and epidemic data. The model provides probability distributions for the time and place of introduction of Zika in Brazil, the estimate of the attack rate, timing of the epidemic in the affected countries, and the projected number of newborns from women infected by Zika. These results are potentially relevant in the preparation and analysis of contingency plans aimed at Zika virus control.
Abstract
We use a data-driven global stochastic epidemic model to analyze the spread of the Zika virus (ZIKV) in the Americas. The model has high spatial and temporal resolution and integrates real-world demographic, human mobility, socioeconomic, temperature, and vector density data. We estimate that the first introduction of ZIKV to Brazil likely occurred between August 2013 and April 2014 (90% credible interval). We provide simulated epidemic profiles of incident ZIKV infections for several countries in the Americas through February 2017. The ZIKV epidemic is characterized by slow growth and high spatial and seasonal heterogeneity, attributable to the dynamics of the mosquito vector and to the characteristics and mobility of the human populations. We project the expected timing and number of pregnancies infected with ZIKV during the first trimester and provide estimates of microcephaly cases assuming different levels of risk as reported in empirical retrospective studies. Our approach represents a modeling effort aimed at understanding the potential magnitude and timing of the ZIKV epidemic and it can be potentially used as a template for the analysis of future mosquito-borne epidemics.
Footnotes
- ↵1To whom correspondence should be addressed. Email: a.vespignani{at}northeastern.edu.
Author contributions: M.E.H., I.M.L., and A.V. designed research; Q.Z., K.S., M.C., A.P.y.P., S.M., D.M., P.P., L.R., and A.V. performed research; Q.Z., K.S., M.C., A.P.y.P., D.M., M.B., and A.V. analyzed data; and Q.Z., K.S., M.C., A.P.y.P., N.E.D., D.P.R., S.M., D.M., P.P., L.R., M.B., M.E.H., I.M.L., and A.V. wrote the paper.
The authors declare no conflict of interest.
This article is a PNAS Direct Submission.
See Commentary on page 5558.
This article contains supporting information online at www.pnas.org/lookup/suppl/doi:10.1073/pnas.1620161114/-/DCSupplemental.
Freely available online through the PNAS open access option.
Spread of Zika virus in the Americas
Article Classifications
- Physical Sciences
- Biophysics and Computational Biology
- Biological Sciences
- Population Biology
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