Study On Spatio-temporal Distribution Of Respiratory Infectious Diseases And Its Relationship With Meteorological Drought In Shandong Province

Objectives1.To understand the epidemic trend of respiratory infectious diseases in Shandong province.2.To investigate the hot spot areas and high happening period of respiratory infectious diseases,and reveal their spatio-temporal aggregation in Shandong Province.3.To identify the lagged effect of meteorological drought on respiratory infectious diseases in Shandong Province,and screen for meteorological drought-related sensitive respiratory diseases.4.To evaluate the impact of meteorological drought on the incidence of sensitive respiratory infections and provide scientific basis for prevention and control of respiratory infections.MethodsShandong province were selected as the study area,with counties as the unit of analysis.Descriptive epidemiological methods were used to analyze the epidemiological characteristics of respiratory infectious diseases.The morbidity and mortality of respiratory infections were firstly described.Atime series was applied to describe the temporal distrib-ution characteristics of respiratory infectious diseases.Secondly,the natural discontinuous point grading method was used to demonstrate the spatial distribution characteristics of respiratory infectious diseases in Shandong Province.The spatial distribution characteris-tics of respiratory infectious diseases were further confirmed by empirical Bayesian and spatial Bayesian smoothing,and the excess risk maps of respiratory infectious diseases were drawn.Finally,the spatial autocorrelation analysis of respiratory infectious diseases in each county was conducted to determine spatial aggregation of each infectious disease.The local spatial autocorrelation analysis was further used to detect the presence of local spatial clustering and the hot spots areas.Based on the spatio-temporal scanning analysis method in SaTScan,the spatio-temporal aggregation of respiratory infectious diseases in Shandong Province was dynamically explored from two perspectives:spatial cluster analysis and spatio-temporal cluster analysis.Jinan,Qingdao,Weifang,Tai’an,Ju county and Huimin county were selected as study sites to research on the relationship between meteorological drought and respiratory infectious diseases.The ecological trend research was conducted to identify meteorological drought-related sensitive infectious diseases.Firstly,we removed the less common diseases according to the incidence of respiratory infectious diseases;secondly,the Wilcoxon rank sum test was primarily used to screen respiratory infectious diseases in exposure,control and lagged periods.Finally,based on the control of potential confounding factors,the negative binomial regression models,zero-expansion negative binomial regression models,and zero-expansion Poisson regression models were selected to determine the relationship between meteorological drought and the morbidity of rough screening disease.Results1.A total of 537,000 cases and 1341 deaths of respiratory infectious diseases were reported in Shandong Province from 2005 to 2014,and the pulmonary tuberculosis had the highest annual incidence（36.45/10⁵）,followed by epidemic parotitis（11.07/10⁵）.For long time scales,the morbidity of respiratory infections had a marked seasonality with high morbidity in winter and spring.For example,the monthly incidence of pulmonary tuber-culosis peaked in January and April.The morbidity of whooping cough was relative stable during the study period.The morbidity of scarlet fever,influenza,and mumps showed an upward trend,while the rest respiratory infectious diseases showed a downward trend.2.The morbidity of respiratory infectious diseases showed significant spatial diversity in Shandong Province.The measles had 60 counties with excess risk（ER）greater than 1,pulmonary tuberculosis had 72,and epidemic cerebrospinal meningitis（DCSM）had 55,which were mainly distributed in the western and southern regions of Shandong Province.Pertussis（49 counties with ER>1）and influenza（45 counties with ER>1）were mainly distributed in the western part of Shandong.Influenza A（H1N1）（39 counties with ER>1）and rubella（69 counties with ER>1）were mainly distributed in the northwestern and central regions of Shandong Province.Scarlet fever and mumps were mainly in the central region of Shandong Province.3.Global spatial autocorrelation analysis showed that there was autocorrelation in respiratory infectious diseases except for DCSM（Moran’s I:0.076⁰.353）.Local auto-correlation analysis showed that the number of high-risk areas of whooping cough,rubella,influenza A（H₁N₁）,tuberculosis,influenza,DCSM,mumps,measles and scarlet fever were 20,7,5,24,14,4,10,23,and 8,respectively.Spatio-temporal scan analysis revealed that influenza A（H1N1）（the relative time was prone to occur in November,2009;RR=39.79）,measles（the relative time was in March,2008;RR=13.38）,tuberculosis（the relative time was in January,2007;RR=2.32）,rubella（the relative time was in May,2005;RR=122.07）,and Scarlet fever（the relative time was in December,2011;RR=9.34）had one agglo-meration area.There were two clustering areas of DCSM（RR values were 23.49 and 14.27in February and March 2005）and mumps（RR values were 4.84 and 60.71 in June 2012and July 2005）.There were three clustering areas of pertussis（the relative times were in July 2007,June 2010 and June 2005;RR values were between 21.44⁴0.96）.Influenza had4 aggregation areas（the relative times were in September 2009,November 2009,December 2013,and March 2010）and the RR values were between 6.65³10.29.4.Tuberculosis was the disease with the highest incidence of respiratory infectious diseases in the study sites（up to 37.68/10⁵）,followed by mumps（18.59/10⁵）.Diphtheria and severe acute respiratory syndrome were not reported during the study period.5.Wilcoxon rank-sum test showed that tuberculosis,measles,DCSM,scarlet fever,and rubella may be meteorological drought sensitive respiratory infectious diseases.The best lagged periods were 1 month,0-1month,and 1 month,3 month and 0 months,and the RR values were 0.989,0.875,1.062,10.734,1.471,and 1.468,respectively.6.Multivariate regression models showed that the risk of developing scarlet fever and rubella increased significantly after meteorological drought.The OR values were 1.207（95%CI:1.172-1.243）and 2.206（95%CI:1.436-3.388）,respectively.The risk of measles decreased after meteorological drought（OR=0.666,95%CI:0.444-0.999）.Conclusions1.Tuberculosis,mumps,measles and influenza are the high incidences and major respiratory infectious diseases in Shandong Province.Seasonal distributions of incidence are observed with most cases occurred in winter and spring,and most of the disease show a downward trend.The morbidity of respiratory infectious diseases has obvious local agglo-meration,mainly in the densely populated areas such as southern and central of Shandong.2.The study identifies a spatio-temporal aggregation zone with spatial autocorrelation and high risk of respiratory infectious diseases in Shandong Province.The hot-spots and spatio-temporal areas of different respiratory infectious diseases are different for each dis-ease.Their spatial agglomeration areas are mostly in the northeast and southwest regions of Shandong,and the relative time is prone to occur in March,November,and December.3.Meteorological drought plays an important role in the spread of rubella and scarlet fever in the population and can increase the risk of rubella and scarlet fever.4.After the meteorological drought occurs,it has a protective effect on the morbidity of measles.