| Background Typhoid and Paratyphoid Fevers(TPF)are acute intestinal infectious diseases,of which pathogenies are Salmonella enterica subsp.enterica serotype typhi and Salmonella enterica subsp.enterica serotype paratyphi A,B,C.TPF is still one of the most important public health problems in the world,and its have been reported as one of the class B infectious diseases in China.Before 1990,TPF incidence between10-50/10 million,2009 has dropped to 1.28/10 million in China,but in some areas the incidence remains higher,and outbreaks frequently.Meteorological factors are one of the factors that affect the outbreak and epidemic of infectious diseases.For example,fecal sewage from infectious sources is affected by meteorological factors such as rain and temperature,leading to drinking water and food contamination,thereby increasing the risk of infection of the population.Objective In this study,we analyzed the relationship between the epidemiological features of TPF and meteorological variables in Hongta district from 1999 to 2015,to provide scientific basis for monitoring and control of TPF.Materials and Methods The case datas of TPF in Hongta district from1999 to 2015 were obtained from China Information System for Disease Control and Prevention.The population data from Hongta district statistical bureau and Statistical Yearbook.Monthly meteorological data from China Meteorological Data Sharing Service System,including monthly average rainfall,monthly average temperature,monthly average relative humidity,monthly average pressure,monthly average rainfall days,monthly average sunshine hours.In this study,the cases of TPF was analyzed by the epidemiological methods,and Chi-square test,concentration method and circular distribution were used to analyze the epidemic characteristics of time,area and population distribution from 1999 to 2015.The relationship between the meteorological factors and the incidence of TPF was analyzed by Pearson correlation analysis,calculate the correlation coefficient r value and P value,and if P value less than or equal to 0.05,there was statistically significant difference;after that,the principal component analysis was used to analyze the main meteorological factors.and Principal component regression analysis was used to identify the main meteorological factors affecting the onset of the disease Statistical analysis of data was by Excel 2010 and SPSS17.0 software.Result 8398 cases of TPF cases were reported in 1999-2015,and in 1999 and 2015 was reported 23,44 cases,respectively.During the period of 1999-2015,the annual growth period,peak period and decline period of TPF cases is from March to May(average monthly growth rate of 63.31%),June to October(the average monthly reduction rate of 2%),November to February(the average monthly reduction rate of25.70%),respectively,and the annual number of cases showed a seasonal increase from March to October,a seasonal decline from November to February the following year.The Concentration and Circular Distribution analysis showed that the incidence of TPF in Hongta district was seasonal,and the peak of onset was August 7th,the epidemic period was from May 5th to November 10 th.Five high-intensity epidemic peak at 2000-2002,2004-2005,2005-2007,2007-2008,2008-2010,the peak period ranged from 12 to 24 months,and the epidemic period ranged from 11 to 40 months.The number of cases ranges from June to October in five peak years of 2001,2004,2006,2007 and 2009 were 86~217,67~215,125~216,97~131,63~95 respectively.The number of cases ranges from June to October in eight low peak years of 1999,2000,2002,2003,2008,2005,2010,2015 were 1~3,1~17,32~60,30~43,46~55,43~78,22~61,2~11.The annual growth period,peak period and decline period of TPF cases were from March to May(monthly average growth rate of 63.31%),June to October(monthly average reduction rate of 2%),and November to February(monthly average reduction rate of 25.70%),respectively.The Concentration and Circular Distribution analysis showed that the incidence of TPF in Hongta district was seasonal,and the peak of onset was August 7th,the epidemic period was from May 5th to November 10th.Onset peak month of TPF with an interval of 35 months,24 months,13 months,39 months,between 2001-2004,2004-2006,2006-2007,2007-2009,respectively.That means about an average of 2 years showing a popular cycle.The number of cases were mainly concentrated in the central city(accounted for64.34% of total cases),and the incidence of TPF in the center city was higher than in the surrounding towns(χ2=3628.386,P <0.05);the ratio of male and female patients was 1.09:1,and the incidence of male is higher than female incidence(χ2=25.850,P<0.05);the highest incidence of age in the top three were 20~29,30~39,10~19 years old,the main incidence of occupational population followed by farmers,students,workers,cadres and staff.The Univariate analysis showed that the monthly average incidence of TPF was positively correlated with monthly average rainfall days(r =0.864,P <0.01),monthly average rainfall(r =0.833,P <0.01),monthly average temperature(r =0.806,P <0.01)and monthly average relative humidity(r =0.706,P <0.05),was negatively correlated with sunshine time hours(r =-0.642,P <0.05),was no correlated with monthly average pressure(r =-0.186,P >0.05);principal component analysis showed that the first principal component(C1)reflects the monthly average rainfall,monthly average temperature,monthly average rainfall days and other information,the Second principal component(C2)reflects the relative humidity and other information;principal component regression analysis showed that monthly average rainfall,rainfall days and temperature were the main meteorological factors that affected the incidence of TPF.Conclusion The incidence features of TPF in Hongta area are seasonal increase,seasonal reduction,periodic epidemic,long-term trend formation,regional and age group concentration;the incidence of TPF is closely related to rainfall days,rainfall,temperature and relative humidity,especially rainfall days and rainfall are more significantly,monthly average monthly average sunshine hours;the accumulation of infectious sources,the formation of heavy pollution sources and the exposed population increase are affecting and driving the relationship between the epidemiological features of TPF and meteorological variables.The corresponding regular pattern,mechanisms,policies and evaluation are contributed to monitor and control TPF and other enteric infections. |
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