Changes in Rodent Abundance and Weather Conditions Potentially Drive Hemorrhagic Fever with Renal Syndrome Outbreaks in Xi’an, China, 2005–2012

Abstract

BackgroundIncreased 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 FindingsData 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.ConclusionsIn 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.

Interannual cycles of Hantaan virus outbreaks at the human–animal interface in Central China are controlled by temperature and rainfall

“…outbreaks of hantavirus infection, the population dynamics of the carrier rodents, and climate variability (14)(15)(16) in Asia (16)(17)(18)(19), Europe (20), and the Americas (21)(22)(23)(24). However, outbreaks of zoonotic hantaviruses do not simply track environmental conditions or rodent dynamics (25,26).…”

A Space-Time Study of Hemorrhagic Fever with Renal Syndrome (HFRS) and Its Climatic Associations in Heilongjiang Province, China

“…Since HFRS is transmitted by reservoir hosts (especially rodents), it is expected that climatic factors (such as precipitation, temperature, humidity, and global climate pattern) should influence human HFRS morbidity by affecting the reproduction and abundance of rodents [3,[23][24][25][26][27]. To some extent, understanding climate change can offer a preliminarily assessment or an early warning concerning the epidemic situation.…”

Upsurge of Rodents’ Population in a Rural Area of Northeastern Iran Raised Concerns about Rodent-borne Diseases

“…Climate change was implicated as the cause of increased rodents' populations in China during 2005 to 2012, which was followed by an outbreak of hemorrhagic fever with renal syndrome. There is a significant correlation between climate changes (seasonal rainfall and temperature) and rodent's densities the outbreaks of diseases as well [29]. Our data from this study shows that the increase in rodent populations in this village had begun in 2007.…”