Ecology and geography of hemorrhagic fever with renal syndrome in Changsha, China.

Hong Xiao,Xixing Zhang,Jian Zhao,Lidong Gao,Biyun Chen,Na Li,Peijuan Zhu,Jianxin Qin,Cunrui Huang,Xiaoling Lin,Huaiyu Tian

doi:10.1186/1471-2334-13-305

Abstract

BackgroundHemorrhagic fever with renal syndrome (HFRS) is an important public health problem in mainland China. HFRS is particularly endemic in Changsha, the capital city of Hunan Province, with one of the highest incidences in China. The occurrence of HFRS is influenced by environmental factors. However, few studies have examined the relationship between environmental variation (such as land use changes and climate variations), rodents and HFRS occurrence. The purpose of this study is to predict the distribution of HFRS and identify the risk factors and relationship between HFRS occurrence and rodent hosts, combining ecological modeling with the Markov chain Monte Carlo approach.MethodsEcological niche models (ENMs) were used to evaluate potential geographic distributions of rodent species by reconstructing details of their ecological niches in ecological dimensions, and projecting the results onto geography. The Genetic Algorithm for Rule-set Production was used to produce ENMs. Data were collected on HFRS cases in Changsha from 2005 to 2009, as well as national land survey data, surveillance data of rodents, meteorological data and normalized difference vegetation index (NDVI).ResultsThe highest occurrence of HFRS was in districts with strong temperature seasonality, where elevation is below 200 m, mean annual temperature is around 17.5°C, and annual precipitation is below 1600 mm. Cultivated and urban lands in particular are associated with HFRS occurrence. Monthly NDVI values of areas predicted present is lower than areas predicted absent, with high seasonal variation. The number of HFRS cases was correlated with rodent density, and the incidence of HFRS cases in urban and forest areas was mainly associated with the density of Rattus norvegicus and Apodemus agrarius, respectively.ConclusionsHeterogeneity between different areas shows that HFRS occurrence is affected by the intensity of human activity, climate conditions, and landscape elements. Rodent density and species composition have significant impacts on the number of HFRS cases and their distribution.

Highlights

Hemorrhagic fever with renal syndrome (HFRS) is an important public health problem in mainland China
In China, HFRS is caused mainly by two types of hantavirus, Hantaan virus (HTNV) and Seoul virus (SEOV), each of which has co-evolved with a distinct rodent host
We investigated the effects of ecological and geographic factors on HFRS occurrence using Ecological niche models (ENMs), and explored the relationship between HFRS cases and rodent hosts by the Markov chain Monte Carlo (MCMC) method, using data from Changsha, China

Summary

Introduction

Hemorrhagic fever with renal syndrome (HFRS) is an important public health problem in mainland China. Hemorrhagic fever with renal syndrome (HFRS) is a group of rodent-borne diseases caused by hantaviruses (HV). It is an important public health problem in China, with 30,000 to 60,000 cases reported annually, accounting for 90% of human cases reported globally over the last 10 years [1]. Hunan Province has become one of the most severely endemic areas in China since the first case was discovered in 1963 It is a traditional and mixed epidemic area, with SEOV the main hantavirus type and Mus musculus, R. norvegicus and A. agrarius the dominant rodent species. Previous studies have found that precipitation, temperature, humidity, normalized difference vegetation index (NDVI), and land use types are important risk factors for HFRS incidence [3,4,5,6]

Objectives

Methods

Results

Discussion

Conclusion