ABSTRACT
Objective:To analyze the epidemic situation of plague among animals in the foci of Meriones unguiculatus in Inner Mongolia Plateau, and to find out key influencing factors affecting the epidemic of the plague, and to provide theoretical basis for the prediction, early warning and risk assessment of the plague. Methods:The monitoring data including gerbils density, gerbils body flea index, plague epidemic intensity, etc., as well as environmental data including temperature, precipitation and El Ni?o activity (Southern Oscillation Index, SOI) from 19 banners (counties, cities and districts) in Ulanqab Plateau area, the foci of Meriones unguiculatus in Inner Mongolia Plateau were selected. The methods of correlation analysis, structural equation model and rank correlation were used to analyze the epidemic and key influencing factors of plague among animals in the foci. Results:The plague epidemic cycle in the foci of Meriones unguiculatus in Inner Mongolia Plateau was 5 to 10 years. The correlation analysis results showed that all the factors had influence on each other. Structural equation model screened out that the main influencing factors of plague epidemic were SOI, gerbils density and temperature. SOI had a negative effect on plague epidemic intensity (-0.022) and temperature (-0.029), while gerbils density had a positive effect on plague epidemic intensity (0.014), and temperature had a negative effect on plague epidemic intensity (-0.065). In rank correlation, when the gerbils density was at a high value, the probability of high plague epidemic intensity in that year was 4/9; when SOI was at a low value, the probability was 5/9; when the temperature was at a low value, the probability was 5/9. When the plague epidemic intensity was at a high value in that year, the probability of the plague epidemic intensity being high in the following year was 5/8; when the gerbils density was at a high value in that year, the probability was 4/9; when SOI was at a low value in that year, the probability was 4/9. Conclusion:Climate and biological factors can affect prevalence of plague, and countermeasures should be taken in advance to prevent plague outbreaks when El Ni?o phenomenon, low temperature, high density of gerbils, and high previous-year prevalence of plague appear.
ABSTRACT
Objective@#To forecast the risk distribution of inter-animal plague in Meriones unguiculatus effectively and provide scientific evidence for prevention and control of inter-animal plague, through studying the correlation between meteorological and environmental factors and inter-animal plague in Meriones unguiculatus.@*Methods@#Positive data of plague bacterial culture in 30 epidemic source areas of Meriones unguiculatus in the Inner Mongolia plateau from 2005 to 2018, including detecting time, number of bacteria, latitude and longitude or detailed location, host type, were from the Chinese Disease Prevention and Control System Plague Prevention Management Information System and related professional institutions for plague prevention and treatment. Logistic regression was used to explore the relationship between the inter-animal plague and climate-related risk factors. The Maximum Entropy (Maxent) model was used to predict the habitat distributions of inter-animal plague, and the receiver operating characteristic (ROC) curve was used to validate the model.@*Results@#There were 11 climatic factors including annual mean temperature, isothermality, temperature seasonality, mean temperature of driest quarter, mean temperature of warmest quarter, mean temperature of coldest quarter, annual precipitation, precipitation seasonality, globcover, normalized difference vegetation index and slope, were related to the outbreak of plague among Meriones unguiculatus and included in the model (OR = 1.302, 0.455, 0.957, 0.930, 4.864, 0.179, 0.986, 1.126, 0.992, 0.981, 0.721, P < 0.01). The increase of annual mean temperature, mean temperature of warmest quarter and precipitation seasonality will increase the risk of animal plague in the plague foci of Meriones unguiculatus; the increase of isothermality, temperature seasonality, mean temperature of driest quarter, mean temperature of coldest quarter, annual precipitation, globcover, normalized difference vegetation index, and slope will reduce the risk of animal plague in the plague foci of Meriones unguiculatus. The areas under the curve (AUCs) of the Maxent model training data and test data were 0.988 and 0.985, the prediction effect of the model was better. The habitat distribution of Meriones unguiculatus plague mainly concentrated in the central and northern Ulanqab plateau, Ordos plateau, and eastern Hetao plain.@*Conclusions@#The use of Maxent model and climate data can predict the potential risks and spatial distribution of animal plague in Meriones unguiculatus; the results are accurate and reliable.
ABSTRACT
Objective To forecast the risk distribution of inter-animal plague in Meriones unguiculatus effectively and provide scientific evidence for prevention and control of inter-animal plague,through studying the correlation between meteorological and environmental factors and inter-animal plague in Meriones unguiculatus.Methods Positive data of plague bacterial culture in 30 epidemic source areas of Merioncs unguiculatus in the Inner Mongolia plateau from 2005 to 2018,including detecting time,number of bacteria,latitude and longitude or detailed location,host type,were from the Chinese Disease Prevention and Control System Plague Prevention Management Information System and related professional institutions for plague prevention and treatment.Logistic regression was used to explore the relationship between the inter-animal plague and climate-related risk factors.The Maximum Entropy (Maxent) model was used to predict the habitat distributions of inter-animal plague,and the receiver operating characteristic (ROC) curve was used to vzlidate the model.Results There were 11 climatic factors including annual mean temperature,isothermality,temperature seasonality,mean temperature of driest quarter,mean temperature of warmest quarter,mean temperature of coldest quarter,annual precipitation,precipitation seasonality,globcover,normalized difference vegetation index and slope,were related to the outbreak of plague among Meriones unguiculatus and included in the model (OR =1.302,0.455,0.957,0.9130,4.864,0.179,0.986,1.126,0.992,0.981,0.721,P ＜ 0.01).The increase of annual mean temperature,mean temperature of warmest quarter and precipitation seasonality will increase the risk of animal plague in the plague foci of Meriones unguiculatus;the increase of isothermality,temperature seasonality,mean temperature of driest quarter,mean temperature of coldest quarter,annual precipitation,globcover,normalized difference vegetation index,and slope will reduce the risk of animal plague in the plague foci of Meriones unguiculatus.The areas under the curve (AUCs) of the Maxent model training data and test data were 0.988 and 0.985,the prediction effect of the model was better.The habitat distribution of Meriones unguiculatus plague mainly concentrated in the central and northem Ulanqabplateau,Ordos plateau,and eastern Hetao plain.Conclusions The use of Maxent model and climate data can predict the potential risks and spatial distribution of animal plague in Meriones unguiculatus;the results are accurate and reliable.