Study On Pathogen Surveillance Of Acute Respiratory Infectious Disease In Jinan Military Command Area

Background: Acute respiratory infectious disease is a kind of important infectious diseases transmitted through air droplets.The pathogens are mainly composed of viruses,bacteria and mycoplasma.Among them,the respiratory tract infection caused by virus infection is the most serious threat to human beings.The pathogenic factors are complex and diverse,which are affected by the biological factors such as the variation of pathogens and different levels of immunity.It is also related to the natural factors such as climate change,air pollution and other social factors such as working condition and living environment.In recent years,SARS,influenza A H1N1,avian influenza H7N9,MERS and other new respiratory infectious diseases have significant impacts on social stability,economic construction and people's health.How can early warning and timely control of new disease outbreaks,become the focus of the world's major public health issues.Different types of respiratory infectious disease surveillance systems were established in many countries to respond to major infectious disease epidemic.China has also joined the global influenza surveillance network in 1981 and has established surveillance systems for influenza and respiratory syndrome.People are more concerned about the newly emerging infectious pathogens such as H5N1,H7N9,and also pay attention to the surveillance of the children,the elderly and inpatient.But there are very few reports about the virus infection rated and the main pathogens of young people and outpatients.Compared with the general population,most of the military personnel are 18-45 years old young-aged and middle-aged people.They are living together and training together,always taking great physical and mental stresses in routine life,and with the high frequency of personnel replacement and exchange.These characters facilitate the occurrence,spread and epidemic of acute respiratory infectious diseases.Analysis of infectious disease data since 2010 shows that the respiratory infectious diseases had becoming the leading infectious diseases,its outbreak number is higher than insect-borne infectious diseases and intestinal infectious diseases.The virus is the most prominent pathogen of the respiratory infectious diseases.Many large-scale outbreaks had occurred and pose a serious threat to the health and combat forces of the army troops.The bio-security alarm was also sounded.Prevention and control of respiratory infections,In the prevention and control of respiratory diseases,in addition to continue to do a good job to enhance the group immunity and cut off the transmission path,the more important is the early detection,early diagnosis and earlywarning,to change the passive treatment for active prevention and control monitoring,and to prevent the epidemic in the bud.In fact,although a number of areas to carry out influenza surveillance and respiratory syndrome monitoring work,but because of different population characteristics and different concerns,the disease prevention and control works lack of targeted guidance.Although few army troops carried out monitoring work,but they fail to achieve the purpose of early warning because the monitoring time is short,the range is small and not scale.To this end,the military is necessary to carry out full-time,all-area monitoring.Through the daily monitoring work,gradually improve the army's acute respiratory pathogen detection and surveillance capabilities,in order to achieve the military early forecast and early warning of infectious diseases and effective control of the epidemic.Meanwhile,by strengthening the discovery and identification capabilities for new infectious disease,to comprehensively strengthen the biological defense capacity of our army.This study relies on the "Army acute respiratory tract infection pathogen surveillance and early warning system" which was establish in 2013,combined with daily infectious disease pathogen surveillance work in military troops,through laboratory testing and epidemiological investigation,to conduct the pathogen spectrum study and etiology variation pattern study in the military troops of Jinan military command area.Objective: This study aims to achieve the following objectives: 1.to understand the pathogen spectrum of pathogens of acute respiratory tract infection in the epidemic season in troops of Jinan military command area,and to reveal the main pathogenic pathogens and key infectious diseases,to explore the epidemic trend and epidemiological characteristics.2.to conduct the in-depth analysis of the high incidence,frequently occur and more harmful major pathogens such as adenovirus,and to explore its regularity of epidemic and variation pattern.So that to provide etiology and epidemiology theoretical support for its prevention and treatment.3.to study and analyze the existing problems in the operation of the disease monitoring system in troops,and to provide reference for further enhancing the surveillance ability of infectious diseases in troops of Jinan military command area,and finally realize the early warning and effective prevention and control of infectious diseases in the army.Methods: 1.Since 2014,relying on the military early warning system of acute respiratory tract disease surveillance system,the respiratory pathogens monitoring system of Jinan military command area was established.This system includes 1 reference laboratory,6 network laboratories and 33 surveillance sentinels.The surveillance quality was controlled by the means including developing the surveillance work management procedures and norms,operational technical training,on-site supervision and inspection and laboratory quality control evaluation.2.The nasal / throat swab specimens and basic information were collected from the emergency patients and inpatients with acute respiratory tract infection in the hospitalwhere the sentinel and the network laboratory are located.A total of 6 viruses were detected by RT-PCR,including influenza A virus,influenza B virus,human adenovirus,human coronavirus,human respiratory syncytial virus and human parainfluenza virus.The descriptive epidemiological analysis method was used to analyze the basic information of the cases and the results of pathogen detection.3.The human adenovirus type 7?HAd V 7?positive specimens were collected and inoculated into the A549 cell line for virus isolation and identification.The whole hexon gene of 21 virus isolates was sequenced and alignment with the similar sequences stored in Genbank.Their mutation and evolution patterns were analyzed.4.Summarizes the existing problems in this acute respiratory disease pathogen surveillance system,and explores the strategies and methods which were needed to improve the quality and ability of these surveillance works in the future.Results: 1.Basic information Mar 2014 to Dec 2016,received a total of 883 cases of nasal / throat swab specimens,of which 285 cases of virus positive samples,the positive rate was 32.28%.Two or more virus co-infection specimens were detected in 7 cases,the detection rate was 0.79%.The numbers of specimens?positive rates of virus detection?of each year during 2014-2016 was 290 cases?24.83%?,301 cases?26.91%?and 292 cases?45.21%?respectively.The detection rate of influenza virus was 20.87%.The detection rates of influenza A?influenza A?,p H1N1,seasonal H3N2 and influenza B were 5.10%,5.21%,4.53% and 5.89% respectively.The detection rates of HAd V 7,HAd V 55,corona virus OC43,corona virus NL63 and parainfluenza virus type 3 were 6.46%,3.40%,1.59%,0.11% and 0.79% respectively.Compared with the same period in Shandong province influenza surveillance data,the positive rate of HAd V and influenza virus is higher,other virus detection rate is lower than the local reports.2.Epidemiology characters The peak incidence of acute respiratory infections is generally from December to February the second year,but epidemic time up to the end of April in troops in coastal areas of Qingdao.The detection rate of influenza virus was 22.89%?76/332?in recruit training units and training institutions.The detection rate of other units was 19.42%?107/551?,especially human adenovirus infection cases were all from recruits training units and training institutions.In the different groups,the compulsory serviceman are the main incidence groups,accounting for 63.39% of all cases,but the case according to different rank statistics show that compared with officer and soldier,men and women,the virus detection rate were no significant difference.Among the symptoms of acute respiratory tract infection cases,fever and cough,respectively,100%,80.94%.Among the symptoms of influenza virus infection cases,headache,fatigue,systemic symptoms were 63.35%,76.44%;In adenovirus infection cases,93.46% of patients show high fever above 39.5 ?,57.47% of the cases has sore throat,and abdominal pain and diarrhea is more prominent.3.Composition of the pathogenic spectrum The data of pathogen surveillance of acute respiratory tract infection in 2014-2016 in Jinan military command area show: The distribution of major pathogens was consistent with the national influenza surveillance data,but the pathogen spectrum varied greatly during each year.In 2014,only influenza A virus,HAd V type 55 and type 7 were detected,accounting for 38.64%,30.09% and 27.27% of all detected pathogens respectively.The adenovirus type 7 was detected in Qingdao area for the first time.All six pathogens,mainly influenza virus,were detected in 2015,and the influenza A virus accounted for 63.89% of the total positive cases.Among them,seasonal H3N2,p H1N1 and untyping influenza were 30.56%,25.00%,8.33 %,respectively.While the influenza B virus accounted for 5.56%.Coronavirus OC43 and NL63 were 19.44%,1.38%,coronavirus OC43 co-infected with parainfluenza virus type 3 accounted for 9.72%.In 2016,the influenza virus was still the highest detection rate of pathogens,accounting for 75.91% of all detected pathogens.The predominant epidemic virus was influenza B virus,accounting for 35.04% of the total detected pathogens,accounting for 46.15% of all influenza viruses.Influenza A H3N2 and p H1N1 were 16.79% and 20.44%,respectively,and the two predominantly took the dominant advantage in different time periods.Adenovirus type 7 and untyping influenza A virus accounted for 24.09%,3.65%.Based on the results of three years of surveillance,influenza virus and HAd V accounted for 94.74% of the total pathogens,the main respiratory pathogens in Jinan military command area.Influenza virus epidemic concentrated in January-February,mainly distributed in scattered form.Adenovirus infection is prone to occur during winter and the period between winter and spring?December and March?,and the aggregation character of outbreaks are obvious,and all outbreaks were occur in recruit training units and training institutions.4.The sequence analysis of hexon gene of HAd V 7 isolates In this study,21 isolates of human adenovirus were successfully isolated.All of them were HAd V subgroup B1.The hexon gene was composed of 2805 bp nucleotides.Sequence analysis showed that the sequence homology of 21 isolates was 99.9% 100%,and that with 0901HZ_Sh X_CHN₂009 Shanxi isolate,CHN_DG01₂011₇P7H7F7 Dongguan isolate and isolate CQ1198 were more than 99.9%.792C-T,1818C-T and 2739C-T mutations were silent mutations,of which 792C-T and 1818C-T were the common variants of adenovirus type 7 isolates after 2000,2739C-T is the unique variation of the virus strain isolated from Qingdao.Conclusions: 1.Pathogen spectrum and epidemiological characteristics of acute respiratory disease occurred in Jinan military command area The positive rate of virus infection was 32.28% in the case of acute respiratory disease in 2014-2016 in Jinan military command area.The pathogen spectrum was mainly composed of influenza A virus,influenza B virus,HAd V,coronavirus and parainfluenza virus.Influenza viruses and HAd V are two of the most dominant pathogens.The peakincidence of acute respiratory infections is from December to February of next year,and the risk of outbreaks of recruit training units and training institutions is higher than that of other units.New recruit and compulsory serviceman are high risk groups.The main clinical manifestations of acute respiratory tract infection are fever and cough,influenza virus infection mostly manifest headache,fatigue and other systemic symptoms;HAd V infection associated with sore throat,abdominal pain and diarrhea.2.Molecular epidemiology study of adenovirus type 7 of Jinan military command area In 2014-2016,there were 2 cases of adenovirus infection,including 1 adenovirus type 55 infection,1 adenovirus type 7 infection.This is the first HAd V type 7 outbreak in Jinan military command area.21 isolates of human adenovirus type 7 were isolated.The hexon gene sequences of these isolates were homologous to other reported strains as high as 99.9%.Although the level of variation is low,but also need to continue to strengthen the monitoring,analysis of the evolution of variability,to provide data support for vaccine and drug research.3.The army's pathogen surveillance network has played an important role in early warning and rapid response to infectious diseases.The next step is to improving the relevant laws,regulations and systems,increasingly improve the relevant oversight mechanisms to strengthen the administrative management,and will further enhance the army's ability of early detection,early disposal of infectious diseases and the level of biological security defense.