| BackgroundTyphoon(TY)is severe storm which usually occurs in the Northwest Pacific and the South China Sea,and is a powerful and profound tropical weather system.Due to the special geographical location,Hainan province of China which is an island will be always affected by typhoon cyclone in summer and autumn.Typhoon brings abundant fresh water and wet air for people.And it also brings a large number of casualties and economic loss.A number of domestic and foreign studies indicated that typhoon and its sequent effect impacted the human endocrine system,nervous system and immune function.It also caused psychological barriers to the victims,even serious mental trauma.In addition,it increased the number of skin diseases,diseases of natural focus,insect-borne infectious diseases,respiratory infectious diseases and gastrointestinal diseases.In the National Notifiable Disease Surveillance System(NDSS),infectious diarrhea other than cholera,dysentery,typhoid and paratyphoid,a term "other infectious diarrhea" is used and is categorized as a notifiable category C infectious disease.NDSS defines infectious diarrhea as a group of human diseases that are mainly caused by microbes(including bacteria,parasites,and viruses)and have diarrhea as the typical symptom.The incidence of infectious diarrhea is very high.And it also severely influences the health of human beings.Depending on the data of WHO,there are nearly 1.7 billion cases of diarrheal disease every year,globally.And around 760,000 children under five years old were killed by diarrheal disease each year.However,the disease could be effectively prevented through safe drinking-water and adequate sanitation and hygiene.Typhoon would lead to the destruction of the living environment,such as water and food contaminated and residence was damaged.These changes will probably cause infectious diarrhea outbreak even prevalent.We choose Haikou city as the study area,explore the influence of typhoon on infectious diarrhea and analyze the related risk factors.Objective1.To explore the impact of typhoons on the prevalence of infective diarrhea in Haikou city from 2010 to 2014.2.To further clarify the prevalence of infective diarrhea in Haikou city during typhoon months.3.To find out the risk factors resulting in the occurrence and prevalence of infective diarrhea during typhoon months.MethodsThe data of infective diarrhea cases,the permanent residents,typhoons,annually average meteorological and on-the-spot epidemiological data in Haikou city were collected.Paired t test and classified x2test were adopted to analyze the significance of typhoons on the prevalence of infective diarrhea in Haikou city.The correlation between the occurrence of typhoons and the prevalence of infective diarrheas was further analyzed using linear and logistic regression analysis.Results1.From 2010 to 2014,a total of eleven typhoons landed in Haikou city.Meanwhile,the incidence of infective diarrhea in typhoon months was higher than that in non-typhoon months(t =4.188,P =0.002).2.The meteorological factors of maximal temperature and relative humidity were statistically and significantly correlated with the incidence of infective diarrhea in simulated liner regression model(F =4.630,P =0.046).It was found that within certain range of threshold values of maximal temperature and relative humidity(maximal temperature in the range of 28.2??33.6? and relative humidity in the range of 74%?84%),the number of infective diarrhea cases would increase about 5 cases when the maximal temperature increased 1 ? on condition that the relative humidity remained stable,and the quantity of infective diarrhea cases would increase about 353 cases when the relative humidity increased 1%on condition that the maximal temperature remained stable.3.The impact of typhoon Rammasun and typhoon Kalmaegi on the incidence of diarrhea in surveyed areas of Haikou city was statistically significant(?2=6.675,P=0.001).The prevalence of infective diarrhea after typhoons was correlate to the experience of typhoon,the increase of disease vectors,without washing hands before eating and after using the bathroom,and eating overnight food with relative risk 2.783(95%CI:1.135?6.823),2.403(95%CI:1.052?5.486),24.151(95%CI:5.653?103.182)and 40.591(95%CI:5.483?300.496).Conclusions1.The prevalence of infective diarrhea during typhoon months was higher than that in non-typhoon months in Haikou city.2.The increase of quantity of infective diarrhea cases was associated with the changes of maximal temperature and relative humidity and the variations of maximal temperature and relative humidity due to typhoons showing liner correlation with the fluctuation of infective diarrhea cases.3.The prevalence and non-prevalence of infective diarrhea in the residents during typhoon months were not correlated with dwelling environment of urban area and rural area.The experience of typhoon,the increase of vectors,do not wash hands before eating and after using the bathroom,and eat overnight food were the risk factors associated with the infection of infective diarrhea after typhoons. |
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