The Analysis And Simulation Of Brucellosis Model In Bayingolin Mongol Autonomous Prefecture Of Xinjiang

Objective: In order to explore the feasibility of epidemic dynamics model,time series model and Richards model for the brucellosis transmission in Bayingolin Mongol Autonomous Prefecture of Xinjiang.According to the actual situation for brucellosis infection in Bayingolin Mongol Autonomous Prefecture,we establish a dynamic model for brucellosis spread and predict the epidemic trend of brucellosis in the future.Above researches laid a scientific theoretical basis for the prevention and early warning of brucellosis.simultaneously,it provide reference for the control measures which have high feasibility.Method: firstly,using the seasonal exponent verify its seasonal variation rule,Establishing a dynamic model with periodic transmission rates,taking the determine parameters value into the model,others parameters can be confirm by least squares estimate,we apply the seasonal dynamic model to simulate the reported data of newly acute human brucellosis cases from 2010 to 2014.MAPE and RMSPE can be used to evaluate the fitting effect of model.Based on the constructed model to predict the future trend of human brucellosis epidemic.Through the PRCC method,it can extract the parameters which have statistically significant for the human brucellosis number.We calculated the basic reproduction number R0 for human brucellosis epidemic and perform some sensitivity analysis of the human brucellosis cases and R0 in terms of model parameters.The prevention and control measures are put forward.Then,the ARIMA seasonal model can be used to study the seasonal volatility of brucellosis.Based on the reported data of monthly human brucellosis cases from 2005 to 2014,we constructed ARIMA(P,D,Q)(p,d,q)S model.The optimal model can be selected by minimum values of AIC,SBC and AICC.According to the optimal model to forecast the epidemic trend of new human brucellosis cases.Finally,Richards model can be applied to analysis the outbreak data.We use the Richards model to fitting the cumulative new number of brucellosis from August 2013 to December 2013.we can analyze the highest incidence of turning pointduring this time,it is helpful to study the effect of intervention measures relative to the turning point,and estimate the basic reproduction number R0.Result: According to the seasonal expontent analysis we can determine the number of newly acute human brucellosis cases in summer and autumn are higher than in the spring and winter.Based on the transmission mechanism analysis of brucellosis epidemic.We proposed a SEIV model with periodic transmission rates to investigate the seasonal brucellosis transmission dynamics among sheep/cattle and from sheep/cattle to humans.fitting the actual number of newly acute human brucellosis MAPE=18.07%,RMSPE=20.89%,it indicate that the fitting effect is perfect.We predict the number of newly acute human brucellosis is increasing and will peak 15325(95%CI:11920-18242)around the summer of 2023,we estimated the basic reproduction number R0=2.5524(95%CI:2.5129-2.6225),it manifest that human brucellosis will remain spread which can not be eliminated.Our study demonstrates that reducing the birth number of sheep/cattle,raising the slaughter rate of infected sheep/cattle,increasing the vaccination rate of susceptible sheep/cattle,and decreasing the loss rate of vaccination are effective strategies to control brucellosis epidemic.The white noise test for the original sequence shown that P<0.05 in the time series model which have the value to research,through the first difference treatment can make the smooth sequence.The optimal mode is ARIMA(1,1,1)(0,1,2)12,at this time,AIC=973.12,SBC=987.02,AICC=973.66,the errors between fitting values and actual values are MAPE=23.82%,RMSPE=29.64%.We predict that the number of new human brucellosis is increasing and will peak around the summer of 91(95%CI:51-131)in June2015.Finally,the errors between the fitting value and the actual value with Richards model are MAPE=6.80%,RMSPE=3.98%.We also estimated that the highest incidence of human brucellosis are occurrence between the June and July of 2014,before the implementation of all kinds of prevention and control measures,we estimate the basic reproduction number R0=1.1207(95%CI:0.6091-1.1379),it indicated that the human brucellosis can not be eliminated.Conclusion: The seasonal dynamic model with periodic transmission rate,ARIMA seasonal model and Richards model can simulate the respective characteristics of the data of human brucellosis epidemic perfectly,it possess of strong scientific and the feasibility is higher,it can provide the prevention and control strategy of human brucellosis before the peak season is coming.