| Objective: To monitor and analyze the avian influenza virus in the environment outside the live poultry market in Jiangxi province.The positive samples were further classified into the H5 subtype,H7 subtype,H9 subtype,mixed type and unclassified type for statistical analysis,so as to understand the distribution and pollution types of each subtype of virus in the external environment.Prediction of the positive rate of avian influenza virus in the external environment by establishing a suitable ARIMA model.Through the above research,scientific basis was proposed for the prevention and control of bird flu epidemic,and corresponding measures were taken.Methods: According to the method of stratified cluster sampling,15 counties and districts are taken as monitoring points in 11 districts of the province,and sampling and testing of the monitoring points are carried out in each quarter from the second quarter of 2015 to the fourth quarter of 2018,and the collected sample types include the poultry excrement,water and the surface of the cage,The surface of the meat chopping board and other environmental specimens shall be slaughtered or placed,and the number of samples collected in each quarter of each monitoring point shall not be less than 30.The collected specimens were detected by real-time fluorescence quantitative PCR,and the samples of influenza A virus nucleic acid positive were detected for H5,H7 and H9 subtype.By using the chi-square test,the obtained data is analyzed,and the difference of the positive rate of the external environmental viruses in different time,regions,places and the like is compared;and the positive rate of the avian influenza virus in the external environment is taken as a time sequence in2015-2018,The appropriate parameters were selected to construct the optimal ARIMA model to predict the positive rate of the external environmental virus in the first quarter of 2019.Results:(1)From 2015 to 2018,A total of 6,652 environmental specimens were collected from the live poultry market in jiangxi province,including 3,437(51.67%)positive specimens of type A,including 391(5.88%)H5 subtype,61(0.92%)H7subtype,1,420(21.35%)H9 subtype,739(11.11%)mixed type and 826(12.42%)unclassified type,with the highest proportion of H9 subtype.The positive rates in the four years were 48.89%,51.53%,51.92% and 53.50%,respectively,with no statistical significance(2=6.369,P=0.095).(2)The total positive rates in the four quarters were 51.63%,51.23%,50.57%and 53.21%,respectively,and the difference was not statistically significant(2=2.690,P=0.442).The quarterly data of different years were analyzed separately,and the positive rate differences of each quarter in 2015(2=12.050,P=0.002),2017(2=56.006,P=0.000)and 2018(2=24.584,P=0.000)were statistically significant.The change of a positive rate is cyclical,and the overall trend is upward,reaching the highest value in the fourth quarter and the lowest value in the second quarter.The change of H5 and H9 subtype positive rate is basically consistent with the change of the total positive rate,while the H7 subtype positive rate is at a low level all year round,with an abnormal increase in the first quarter of 2017.(3)Specimens of different types of virus positive rate respectively is 64.21%,the slaughter of poultry excrement and urine or put meat chopping board surface polished content 61.30%,basket surface polished content 51.40% 45.15%,poultry drinking water 46.95%,other specimens,the specimens of each type of positive difference was statistically significant(chi-square = 118.563,P = 0.000),after comparing the two,the poultry excrement and chopping board surface to wipe the virus positive rate is highest,followed by cage surface polished specimens,poultry virus positive rate minimum drinking water and other specimen.In terms of subtype composition,poultry feces and other specimens are dominated by H9 subtype and mixed virus,while table surface wipes,cage surface wipes and poultry drinking water are dominated by H9 subtype and unclassified virus.(4)Virus positive rate of different types of places respectively for the live poultry market reached 55.44%,76.00% live poultry wholesale market,poultry farms(households)21.76%,2.21%,poultry slaughtering factory differences statistically significant(chi-square = 536.939,P = 0.000),the pairwise comparison,all places virus positive differences were statistically significant,namely live poultry wholesale market positive rate is highest,lowest scale poultry farms.The virus in the livepoultry wholesale market is mainly H9 subtype,the urban and rural live poultry market is mainly H9 subtype,mixed type and unclassified type,the poultry slaughtering factory is mainly H9 and H7 subtype,and the poultry farms(households)only have two subtypes of H5 and H9 virus.(5)The positive rate of the virus in the external environment of the 15 monitoring sites was statistically significant(2=1159.110,P=0.000).The positive rate of the virus in leping city was the highest(79.09%),and the positive rate of the virus in yujiang county was the lowest(14.44%).In terms of the composition of subtypes,the H9 subtype accounted for the highest proportion in most areas,and mixed strains dominated in anyuan county,unclassified viruses dominated in yugan county,chongren county and wanchai county,H5 subtype dominated in leping city,and the monitoring site with the highest proportion of H7 subtype was yujiang county.There was no significant differences in the total positive rate between poyang lake monitoring sites and other monitoring sites(2=0.002,P=0.963).For each subtype,the positive rate of H5 subtype at poyang lake monitoring site was higher than that at other monitoring sites(2=40.511,P=0.000),and the positive rate of mixed virus at other monitoring sites was higher than that at poyang lake monitoring site(2=4.849,P=0.028).The total positive rate of virus was highest in the non-epidemic surveillance sites than in the epidemic surveillance sites(2=64.668,P=0.000).For other subtypes,the positive rate of H7 subtype was higher than that of other monitoring points(2=36.060,P=0.000),and the positive rate of H5 subtype and unclassified virus was higher than that of other monitoring points(2=11.902,P=0.001).2=103.714,P=0.000).(6)The optimal model was evaluated as ARIMA(2,0,0),and the positive rate of avian influenza virus in the external environment of jiangxi province in the first quarter of 2019 was predicted to be 49.53%.Conclusion: The positive rate of avian influenza virus in the external environment of jiangxi province is relatively high,mainly of H9 subtype virus,and the positive rate of unclassified virus has an increasing trend,so it is necessary to strengthen virus subtype monitoring.The variation of virus positive rate was seasonal,and the variation tendency of H5 and H9 subtypes was consistent with the overallpositive rate.It is necessary to strengthen the supervision and management of the live poultry wholesale market and the urban and rural live poultry market.The predicted progressive rate of avian influenza virus in jiangxi province in the first quarter of2019 was 49.53%. |
PDF Full Text Request