Prediction Of The Distribution Of Four Species Of Tick-borne Spotted Fever Group Rickettsia

With the global climate change,the vigorous development of trade and the increase of human activities,tick-borne diseases will expand geographical scope and affect human health.Spotted fever Rickettsia(SFGR)is widely found in ticks all over the world.Ticks transmit it to host animals and humans through bites,resulting in spotted fever,which causes serious harm to the development of animal husbandry and human health.Therefore,studying the geographical distribution of Rickettsia and the environmental factors driving its distribution are very important for identifying potential risk areas and preventing disease outbreaks,and provide a theoretical basis for rickettsia disease surveillance and prevention and control.In this study,the GPS coordinates of ticks infected with four kinds of spotted Rickettsia:Rickettsia aeschlimannii,R.conorii,R.raoultii and R.rickettsii were counted,and the maximum entropy model was used.based on modern climate and four future climates(SSP126,SSP245,SSP370,SSP585),the suitable growth zone of ticks infected with spotted fever rickettsia was predicted and the environmental variables affecting the distribution of suitable growth zone were analyzed,and then the spread range of four kinds of Spotted Rickettsia and the dominant environmental factors were speculated.The results show that:(1)Under the current climatic conditions,the potential suitable areas of ticks infected with R.aeschlimannii are mainly located in Europe,the west of Asia,the north and east of Africa,the south of Oceania and the coastal areas of western South America.In China,the suitable growth area is located in the Loess Plateau and 23°N～29°N.Under the future climatic conditions,the future potential suitable area of ticks infected with ticks tends to decrease,and the main environmental impact factor is the average temperature in the wettest season.(2)Under the current climatic conditions,the potential suitable areas of ticks infected with R.conorii are mainly located in southeastern Asia,southwestern Europe,central and southern Africa,the eastern and western coastal areas of North and South America and southern Oceania.In China,the suitable growth area is located in the Yunnan-Guizhou Plateau,the middle and lower reaches of the Yangtze River plain,the southeast hills,Sichuan Basin,Taiwan,Tarim Basin and Loess Plateau.Under the future climatic conditions,the area of the suitable growing area has almost no change in the world,but it spreads northward in the suitable growing area in southeastern China,and the risk area in Xinjiang increases.The main environmental impact factor is the average annual temperature.(3)Under the current climatic conditions,ticks infected with R.raoultii are located in southeastern Asia,southwestern Europe,north-central North America,central Asia,southern South America and southern Oceania.Within China,the suitable growth zone is located in eastern China and northwest Xinjiang.Under the future climatic conditions,the potential suitable areas of both the world and China tend to spread.The main environmental impact factor is the average annual temperature.(4)Under the current climatic conditions,the potential suitable growth areas of ticks infected with R.rickettsii are located in southeastern Asia,central and southern Africa,south-central Europe,southern North America,southeastern South America and southern Oceania;in China,the suitable areas are located in the Yunnan-Guizhou Plateau,the plains of the middle and lower reaches of the Yangtze River,southeast hills,Sichuan Basin,Hainan Island,Taiwan,Xinjiang,Henan and Shandong.Under the future climatic conditions,the potential suitable areas of the world and China tend to spread northward.The main environmental impact factor is annual precipitation.