Research On The Geographical Regularity And Environmental Mechanisms Of The Epidemic Disasters In Fujian Province During The1368AD-1644AD Period

Diseases have been in existence since ancient times. Infectious diseases do more harm to human, and the pandemic prevalence of them leads to epidemic disasters. During the277years of Ming dynasty, Fujian province had occurred109epidemics, involving79years and243counties totally, with epidemic frequency of28.5%. These epidemics broke out slightly more in autumn and winter, and slightly less in spring and summer, we11-distributed in each season. The epidemics occurred most frequently during Zhengde Era, Chenghua Era and Jiajing Era in middle Ming dynasty, followed by Chongzhen Era and Wanli Era in late Ming dynasty, and the lowest epidemic frequency appeared in the early stage of Ming dynasty. Overall, the epidemic frequency of Fujian province has been rising slowly with cyclical fluctuation during Ming dynasty. The trend line of epidemic frequency shows as letter "N", with two cycles. The first cycle is from the year of1370to1609, especially the90years during1470to1560, the epidemic years of which occupied59.04%of the total epidemic years of Fujian province. The second cycle is extended to Qing dynasty.The spatial distribution of epidemics in Fujian province during Ming times is unbalanced. Epidemics mainly happened in the northern regions, and the east and west sides of the northern regions occurred more epidemics than that of the central regions. North of the line between Jianning and Fuqing County, especially the western regions of north Fujian province and the coastal regions of east Fujian province, has the highest epidemic occurrence. In the coastal Fujian province, Zhangzhou prefecture, Funing prefecture and Fuzhou prefecture in the southern and northern sides appeared higher epidemic frequency than the middle area. In the north Fujian province, epidemics tend to occur in Shaowu prefecture, Jianning prefecture and Yanping prefecture. County of Shaowu, Funing, Changle, Gutian and Guangze each has10epidemic years, with the highest epidemic frequency in Fujian, whereas Zhengde Era, Jiajing Era, Chenghua Era, Yongle Era and Wanli Era have the most epidemic counties. The epidemic focus is around Youxi county and Dehua county, close to the geographical geometry center of Fujian The variation trend of epidemic focus shows as the number "7", which is consistent with the process of population migration and regional development. Epidemic hot spots are mainly distributed in Shaowu prefecture, Fuzhou prefecture and Funing prefecture, which is located in the northwestern and northeastern Fujian province. Cold spots are mainly distributed in Yongchun county of Quanzhou prefecture, and Shanghang and Yongding county of Tingzhou prefecture in south Fujian province. Other regions are the transition zones.These spatial and temporal distribution characteristics are closely related to the climate change in Ming dynasty, the regional environmental features and the natural disasters of Fujian province. Natural environmental factors such as mountainous topography, hot climate, thick forests, dense water system, manifold creature species, and social factors such as the growth and migration of population, the connection of land and water, the lack of food, the disturbance of society, the superstitious customs, all of these provided conditions, medias and receivers of epidemics, and lead to the occurrence and spread of epidemics within certain spatial and temporal ranges.As to climate change, the ten-year epidemic index of Fujian province in Ming dynasty is negatively correlated to the ten-year cold winter index, showing that epidemics tend to be more frequent when the climate turns colder. The variation of temperature had caused the cyclical fluctuation of epidemics, and the regions suffered more serious frozen injury had higher epidemic occurrence. The increase of cold winter years lead to more epidemics in the winter, thus making the seasonal distribution of epidemics appeared evenly. As to natural disasters, such as floods, droughts, earthquakes, and wind damages are the major natural disasters of Fujian. Natural disasters had high degree of coupling with the spatial and temporal distribution of epidemics, with correlation index of0.541, which declared that there is a causal relationship between them.