Ecological Study On The Incidence Of Human Brucellosis And The Livestock Development And Meteorological Factors In China

Objective:Brucellosis is a common zoonotic disease,and its animal hosts are mainly cattle,sheep,pigs and dogs.People mainly obtain brucellosis by contacting with infected animals or their unpasteurized dairy or meat product.The Brucella which can cause brucellosis in humans are mainly B.melitensis,B.abortus,B.suis and B.canis.Brucellosis is a chronic systemic disease.The main symptoms of brucellosis in humans are fever,night sweats,muscle or joint pain,weight loss,accompanied by serious complications such as meningitis,endocarditis and orchitis.Brucellosis can cause abortion or infertility in animals.Because brucellosis is a very serious threat to human health and animal husbandry,prevention and control of brucellosis has become a worldwide public health concern.Countries had adopted various strategies and measures for prevention and control of brucellosis,such as animal vaccination and test-and-slaughter.However,except for a few countries with more developed economies that have achieved very good control or eradication effects,brucellosis is under controlled in economically underdeveloped regions such as Africa,Asia,South America and the Mediterranean,and remains a widespread infectious disease.Since the beginning of the 21st century,the brucellosis epidemics in China has continued to rise and expand.Domestic and foreign researches reported that the brucellosis transmission might have relationship with various factors such as ecological environment,occupational exposure,animal host density,tourism and climatic conditions.However,relevant research in China is still insufficient and needs further exploration.Methods:The epidemiological distribution of human brucellosis epidemic in China was described,including time distribution and regional distribution.The trends of livestock stocks in China and the incidence of human brucellosis were described,and Spearman correlation analysis and Poisson regression were adopted to explore the correlation between them.The temporal trends of human brucellosis incidence and meteorological conditions in Inner Mongolia,Henan,Shanxi,and Liaoning provinces were described.The impact of meteorological factors on the brucellosis epidemic in China were explored using the Granger causality test and the Autoregressive Distribution Lag model(ADL)at the provincial,municipal,and county levels,and the fitting and prediction effects of models were evaluated.Results:1.The incidence of brucellosis in China was generally on the rise from 2010 to2016,and the crude incidence rate has increased from 2.53 person/100,000 in 2010 to 3.45person/100,000 in 2016.The highest peak,4.22person/100,000,reached in 2014.The incidence of human brucellosis is seasonal,with cases mainly concentrated between March and August each year.The brucellosis cases in China were mainly concentrated in the north,and the incidence rate in Inner Mongolia was always the highest.The incidence of brucellosis in the southern provinces also increased and year by year spread.All southern provinces reported human brucellosis cases since 2015.2.Spearman correlation analysis and Poisson regression analysis showed that the incidence of human brucellosis significantly correlated with the amount of sheep and goat stocks,and the Spearman correlation coefficient with sheep stocks was 0.6558,which was significantly higher than that of goats.3.The cross-correlation analysis showed that the incidence of brucellosis and the temperature of 4 months lag had the highest correlation coefficient.Granger causality test and ADL model results showed that temperature and wind speed may be the climatic factors affecting the monthly incidence in the four provinces and temperature in four cities and four counties was a risk factor affecting the monthly incidence,with one to six months lag period.According to the ADL model fitting parameter R~2 and the model prediction parameter Root Mean Squared Error(RMSE),the provincial and municipal models had good fitting and prediction effects.Conclusion:1.Overall,the incidence of human brucellosis in China was still on the rise between 2010 and 2016,with a slight downward trend since 2015.2.Incidence of human brucellosis had strongly correlation with the amount of sheep and goats stocks,especially the stock of sheep.3.Significant correlation existed between the spread of brucellosis in China and temperature,and the ADL model has certain value in the evaluation of brucellosis epidemics.