ABSTRACT
Objective To evaluate the effects of environmental factors the distribution of Ixodes persulcatus, and to predict the future suitable habitats of I. persulcatus in China. Methods The known distribution sites of I. persulcatus in China were captured from national and international published literatures. The effects of 14 environmental factors on the distribution of I. persulcatus were examined using the Jackknife test, including mean annual temperature, mean monthly temperature range, isothermality, temperature seasonality, maximum temperature of the warmest month, minimum temperature of the coldest month, temperature annual range, mean temperature of the wettest quarter, mean temperature of the driest quarter, mean temperature of the wet-test quarter, mean temperature of the coldest quarter, annual mean precipitation, precipitation of the wettest month, precipitation of the driest month, precipitation seasonality, precipitation of the wettest quarter, precipitation of the driest quarter, precipitation of the warmest quarter, precipitation of the coldest quarter, elevation, slope, aspect and vegetation. The suitable habitats of I. persulcatus were predicted in China using the maximum entropy model and ArcGIS 10.7 software with the environmental factors. Results Currently, the highly suitable habitats of I. persulcatus covered an area of 886 600 km2 in China, which were predominantly located in northeastern China. The environmental factors that contributed more than 10% to the distribution of the suitable habitats of I. persulcatus in China included annual temperature variation range (39.1%), the coldest quarterly precipitation (23.2%), and the annual mean precipitation (11.9%). Based on the maximum entropy model, the suitable habitats of I. persulcatus were predicted to show a shrinking tendency towards northeastern China in 2070. Conclusions The suitable habitat of I. persulcatus strongly correlates with temperature and precipitation, and climate and environmental changes may lead to shrinking of the future suitable habitat of I. persulcatus in China.
ABSTRACT
Objective To study the co-infection of tick-borne pathogens in Ixodes persulcatus collected in Charles Hilary,Xinjiang Uygur autonomous region (Xinjiang).Methods Ticks were collected by flagging in grassy areas in Charles Hilary,Xinjiang from June 2012 to June 2013.The 5S-23S rRNA intergenic region from Borrelia (B.) burgdorferi,16S rRNA gene from Anaplasma,ompA gene from spotted fever group Rickettsia,comI gene from Coxiella (C.) burneti and Nss-rRNA gene from Babesia were amplified with nested polymerase chain reaction (nested PCR),respectively.Results Among 204 lxodes persulcatus,104 were positive for tick-borne pathogens with the positive rate of 50.98％,and among them the positive rates of B.burgdorferi,spotted fever group Rickettsia and Anaplasma phagocytophilum were 34.31％ (n =70),28.92％ (n =59),9.31％ (n =19),respectively.And no C.burnetii and Babesia were detected.The overall co-infection rate was 19.12％ (39/204),the co-infection rate was 16.18％(33/204) for B.garinii and spotted fever group Rickettsia,4.90％ (10/204) for B.burgdorferi and Anaplasma phagocytophilum,2.94％(6/204) for spotted fever group Rickettsia and Anaplasma phagocytophilum and 2.45％ (5/204) for B.burgdorferi,Anaplasma phagocytophilum and spotted fever group Rickettsia.Conclusion The results indicated that the natural co-infections of B.garinii,B.afzelii,Anaplasma phagocytophilum and spotted fever group Rickettsia existed in Charles Hilary Ixodes persulcatus collected in Xinjiang.