Distribution Patterns Of Rodent Plague And Its Host Rodents In China

Plague is a severe infectious disease, which occurs among rodents firstly, then infect humans in certain conditions. Early detecting rodent plague is helpful for us to take measures to keep away from the plague. In recent years, plague rebounded, so it is important to understand the geographical distribution and environmental factors of plague and rodents to control rodent plague effectively and prevent human plague to occur. This study analyzed the host rodent species richness using GIS techniques, and analyzed the relationship between the species richness of host rodents and environment factors in national wide, and the principal factors that affected the rodent plague were analyzed respectively using correlation analysis and principal component analysis. On this basis, we investigated the occurrence of rodent plague under the future climate change of China.There were 56 rodent hosts of plague in China accounted for 25.57%of the total glires in China, the xerophilous and the hygrophilous glires accounted 50% and 42.86% of the total rodent hosts of plague respectively. The distribution of species richness show that there were the highest species richness of host rodents in the boundaries of arid and monsoon regions. And the rodent host abundance was very significantly positive correlated with annual average relative humidity, annual temperature, annual rainfall, the number of vector fleas, Yersinia pestis distribution, altitude, and altitude difference; significantly negatively correlated with annual total thermal radiation, annual sunny hours, annual aridity, and number of soil and landscape types; and not significantly correlated with number of vegetation types.The rodent plague occurred in 155 counties in China during the period of 1976-1996. According to geographical divisions of plague in China, counties where the rodent plague occurred of the Southwest Mountain area, Inner Mongolia grassland, the southeast coastal areas and western highland region were respectively 45.45%,26.45%,23.87%and 3.23%of the total.The occurrence of rodent plague was very significant positive correlated with the number of vector fleas, annual aridity, the number of soil types, annual sunny hours; and number of vegetation types; and was significantly negatively correlated with annual average relative humidity, annual temperature and rainfall. The factor analysis on the environmental variables which affected the occurrence of rodent plague revealed that numbers of vector fleas, annual temperature, annual rainfall, annual average relative humidity and the annual sunny hour as a vector and climate factor played a dominant role; that landscape factor, which was composed of altitude difference and number of vegetation, soil and geomorphic types was another principal factor; and that the third represented topography and host factor. In addition, the occurrence of plague had a certain relationship with population density and socio-economic activities, the higher degree of urbanization, the lower the risk of plague occurred.