Effect Of Temperature On Bacillary Dysentery And Its Interaction With Other Meteorological Factors

BackgroundAt present,the global climate is undergoing a series of changes characterized by climate warming,and China also shows great similarity.In recent 100 years,the average surface temperature in China has been increasing,the annual precipitation has also shown a trend of slow growth,and the frequency and intensity of abnormal climate change and extreme weather events have also increased significantly.The increasing concentration of CO2 in the atmosphere and the increase of other greenhouse gases may be the main causes of climate change in China.According to the forecast of the weather change in the 21st century,the average surface temperature will continue to rise in the next 20 years,and the annual precipitation in most areas of China will continue to increase.Global warming is a large-scale,wide-ranging,deep-impact challenge for human beings at present.Under this background,it is of great public health significance to study the impact and mechanism of climate change on the field of human health.Bacillary dysentery(BD)remains a serious global health problem,especially in developing countries,causing large numbers of diarrhea and deaths occur every year,many in children under the age of five.As a legally reported infectious disease,the incidence of BD in China is still severe,especially in less developed areas.As a common intestinal infectious disease,the growth,propagation,and transmission of BD pathogens are easy to be affected by meteorological factors.At present,many studies on the relationship between meteorological factors and BD have been carried out.Due to the different economic level,demographics and health intervention measures in different research areas,there are regional differences in the types and degrees of the effect of meteorological factors on BD,and the conclusions are not always the same.Besides,the interaction between meteorological factors on BD is still unclear.Objective1.To analyze the epidemic situation of BD in seven study areas of China.2.To investigate the effect of ambient temperature on the incidence of BD.3.To explore the effect of interaction between air temperature and other meteorological factors on BD,and to provide scientific basis for the prevention and control of BD under different weather conditions.MethodsDaily data of BD cases and meteorological factors from 2014 to 2016 were collected.A generalized additive model(GAM)was conducted to explore the relationship between meteorological factors and BD.Then a distributed lag non-linear model(DLNM)was developed to assess the lag and cumulative effect.Finally,the GAM and a weather-stratified model were used to explore the interactive effect between temperature and other meteorological factors on BD.Results(1)A total of 49760 cases of BD were reported in seven cities over the study period,of which the cases and incidence of BD were the highest in Beijing.The incidence of BD in different cities showed a decreasing trend and regular seasonal in different degrees,and summer and autumn were the high incidence period of BD.The incidence of male was more than that of female.The peak age was 0-5 years old and 30-59 years old.(2)Mean temperature had a nonlinear effect on the incidence of BD.When mean temperature of Beijing was higher than 10?,each 2? rise in temperature caused a 1.44%(RR=1.01,95%CI:1.00?1.02)increase in the number of cases of BD at lag 4,and each 2? rise in temperature can increase the number of cases by 4.53%(RR=1.05,95%CI:1.02?1.07)at lag 0?lag 7 days.When the average temperature was higher than the median,each 2? rise in temperature in Harbin,Hefei,Shenzhen,Wuhan and Xining caused a 4.42%,6.05%,4.12%,2.38%and 10.63%increase in the number of case of BD at lag 6,lag 4,lag 3,lag 2 and lag 0,respectively.The effect of mean temperature on the incidence of BD was not statistically significant in each delayed day in Chengdu.However,each 20C rise in temperature can increase the number of cases by 12.10%at lag 0?lag 7 days(3)The effect interaction of the association between wind speed,humidity and temperature was observed in Beijing,Wuhan and Xining.The incidence of BD increased under the condition of high temperature,low wind speed and high humidity.ConclusionThe incidence of BD in Beijing was the most in study cities,and was higher in summer and autumn.The incidence in male was more than in female.The peak age of BD was 0-5 years old and 30-59 years old.Our study indicates that temperature is significantly associated with the risk of BD in the study areas,and the effect can be modified by wind speed and humidity.Public health professionals and medical service providers should pay more attention BD prevention and control when the weather condition of both low wind speed high humidity and high temperature would occur.