The Spatiotemporal Popularity Characteristics And Occurrence Risk Analysis Of Highly Pathogenic Avian Influenza H5N6 Subtype

As a highly contagious,acute and severe infectious disease mainly infecting poultry,HPAI is caused by influenza A virus of Influenza virus genus of Orthomyxoviridae.It spreads rapidly in birds,with great harm and high mortality.It was listed as a notifiable animal disease by the World Organisation for Animal Health.Since 2014,HPAI H5N6 has broken out on a large scale in Vietnam,Laos,Myanmar,Philippines,China,South Korea,Japan.Severe HPAI H5N6 outbreak has caused huge economic losses to the poultry industry and posed a huge threat to public health.Therefore,it is significant to understand the epidemic characteristics of HPAI H5N6 in China and neighboring countries in recent years,and to explore its occurrence and transmission risk in China.This study collected various information including HPAI H5N6 epidemic data,climate and environment data,susceptible animal distribution data,traffic data,and trade data.Using geographic information technology and spatiotemporal analysis technology,combined with the two dimensions of time and space,the distribution characteristics and propagation trends of HPAI H5N6 in China and neighboring countries was visualized.Two machine learning methods,the Max Ent model and the Random Forest model,were used to explore the occurrence and spread risk of HPAI H5N6,and to reveal the main factors affecting the occurrence and spread of HPAI H5N6.The research contents include:(1)The spatial distribution patterns of HPAI H5N6 in China and neighboring countries were revealed by global spatial autocorrelation and local spatial autocorrelation.The results of the global spatial autocorrelation showed the distribution of HPAI H5N6 in 2014 and 2019 showed a random pattern,and the distribution from 2015 to 2018 and 2020 showed a clustered pattern,when all administrative regions in China and neighboring countries were considered as a whole.The results of the local spatial autocorrelation showed the distribution of HPAI H5N6 in some provinces in Central China,Southwest China,and South China,the eastern coastal provinces in Vietnam,and most provinces in North and West Korea had a high degree of aggregation.(2)Through the directional distribution analysis and spatiotemporal aggregation analysis,the spatial dissemination trend and spatiotemporal development of HPAI H5N6 in China and neighboring countries were explored.The results of directional distribution analysis showed the spread of HPAI H5N6 in China and neighboring countries presented a significant directional distribution feature from 2014 to 2020,and the spread direction was northeast to southwest.The results of spatiotemporal aggregation analysis showed there were six statistically significant spatiotemporal aggregation areas of HPAI H5N6 in China and neighboring countries.Both the first and fifth spatiotemporal aggregation areas are located within the boundaries of Vietnam.Both the secondary and third spatiotemporal aggregation areas are located within the boundaries of Korea.The fourth spatiotemporal aggregation area is located in southern China.The sixth spatiotemporal aggregation area is located within the Philippine border.(3)Through the Max Ent model,the environmental suitability of HPAI H5N6 in China was analyzed,and the environmental factors suitable for the occurrence of HPAI H5N6 were revealed.Combined with the distribution density map of HPAI H5N6 susceptible animals,the occurrence risk of HPAI H5N6 in China was explored.The results showed the most suitable habitats for HPAI H5N6 in China were mainly concentrated in Central China,East China,South China and Southwest China.Altitude(elev),precipitation in the driest month(bio14),average annual water vapor pressure(vapr),precipitation in the warmest month(bio18),and precipitation seasonality(bio15)are important environmental factors affecting the environmental suitability of HPAI H5N6.The high-risk areas of HPAI H5N6 in China are mainly concentrated in Shandong Province,Jiangsu Province,Henan Province,Hubei Province,Sichuan Province,Guangxi Zhuang Autonomous Region,Guangdong Province,Taiwan Province.(4)The Random Forest model was used to explore the spread risk of HPAI H5N6 in China,revealing the main factors affecting the spread of HPAI H5N6.The results showed the spread risk areas of HPAI H5N6 in China are mainly located in southern China.The three variables of poultry market(marketpoint),main road(road),and water body(waterbody)have the greatest impact on the transmission risk of HPAI H5N6.In summary,this study combines two dimensions of time and space to explore the spatiotemporal epidemic characteristics of HPAI H5N6 in China and neighboring countries.The occurrence and transmission risk of HPAI H5N6 was analyzed by machine learning models.The analysis revealed important factors affecting the occurrence and spread of HPAI H5N6,and obtained a map of the occurrence and spread of HPAI H5N6 in China.Epidemic surveillance,prevention,and control can be carried out in a planned way based on the results.Targeted prevention and control work was carried out in areas with the risk of occurrence and transmission of HPAI H5N6.The scientific basis for HPAI H5N6 prevention and control strategies,which carried out by government and animal epidemic prevention departments,is provided.