Changes in rodent abundance and weather conditions potentially drive hemorrhagic fever with renal syndrome outbreaks in Xi'an, China, 2005-2012

PLoS Negl Trop Dis. 2015 Mar 30;9(3):e0003530. doi: 10.1371/journal.pntd.0003530. eCollection 2015 Mar.

Abstract

Background: Increased risks for hemorrhagic fever with renal syndrome (HFRS) caused by Hantaan virus have been observed since 2005, in Xi'an, China. Despite increased vigilance and preparedness, HFRS outbreaks in 2010, 2011, and 2012 were larger than ever, with a total of 3,938 confirmed HFRS cases and 88 deaths in 2010 and 2011.

Methods and findings: Data on HFRS cases and weather were collected monthly from 2005 to 2012, along with active rodent monitoring. Wavelet analyses were performed to assess the temporal relationship between HFRS incidence, rodent density and climatic factors over the study period. Results showed that HFRS cases correlated to rodent density, rainfall, and temperature with 2, 3 and 4-month lags, respectively. Using a Bayesian time-series Poisson adjusted model, we fitted the HFRS outbreaks among humans for risk assessment in Xi'an. The best models included seasonality, autocorrelation, rodent density 2 months previously, and rainfall 2 to 3 months previously. Our models well reflected the epidemic characteristics by one step ahead prediction, out-of-sample.

Conclusions: In addition to a strong seasonal pattern, HFRS incidence was correlated with rodent density and rainfall, indicating that they potentially drive the HFRS outbreaks. Future work should aim to determine the mechanism underlying the seasonal pattern and autocorrelation. However, this model can be useful in risk management to provide early warning of potential outbreaks of this disease.

Publication types

  • Historical Article
  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Animals
  • Bayes Theorem
  • China / epidemiology
  • Disease Outbreaks / history
  • Disease Outbreaks / statistics & numerical data*
  • Hantaan virus*
  • Hemorrhagic Fever with Renal Syndrome / epidemiology*
  • History, 21st Century
  • Humans
  • Incidence
  • Models, Theoretical
  • Poisson Distribution
  • Population Dynamics
  • Rodentia / physiology*
  • Seasons*
  • Temperature

Grants and funding

This research was supported by Ministry of Science and Technology, China, National Research Program (2012CB955501, 2012AA12A407), the National Natural Science Foundation of China (41271099). BC was partially supported by the European Commission Seventh Framework Programme (FP7/2007-2013) for the DENFREE project under grant agreement no. 282-378. BG is supported by the Science and Technology Directorate, Department of Homeland Security contract HSHQDC-12-C-00058, the Bill and Melinda Gates Foundation. Luis and Grenfell are supported by the RAPIDD program of the Science and Technology Directorate, U.S. Department of Homeland Security, and the Fogarty International Center, NIH. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.