Investigation On The Coinfection Of Emerging Tick-borne Pathogens Of In Ticks At Heilongjiang Ports

Objective:The aim of the present dissertation is to investigate the ticks and their infection and multiple infection with emerging tick-borne pathogens in Heilongjiang ports of Mishan,Suifenhe,Jiayin,Dongning,Hulin,Tongjiang,Xunke,Luobei,Mudanjiang,Heihe,Raohe along the China-Russia borders.Method:Following the comprehensively information of forest vegetation,ecological niches and clinical records of tick borne disease in Heilongjiang ports,we choose Mishan,Suifenhe,Jiayin,Hulin,Tongjiang,Dongning,Luobei,Mudanjiang,Heihe,Xunke,Raohe as the sample sites.Blanket-dragging on vegetation was utilized to obtain unfed ticks in all the 11 ports from April 2014 to Oct 2015.Ticks collected were identified to species level following the taxonomic key and recorded individually.Each tick were grounded in liquid nitrogen,and 200 mg of the homogenate was transferred into a centrifugal tube for DNA extraction.The tick DNA was extracted according to the guidance of DNeasy Blood and Tissue Kit(Qiagen,Hilden,Germany).DNA extracts were used as templates for PCR or nested PCR assays with primer sets specific to five kinds of emerging tick-borne pathogens,including Borrelia burgdorferi,spotted fever group rickettsiae,Anaplasma phagocytophilum,Babesia spp.and Bartonella spp..And the positive amplicons were further sequenced with the same primer sets and analyszed to identify the genetic strains of the pathogens by the molecular data.Results:1.Ticks collectedA total of 1306 ticks were collected and classified into four species in 3 genera: Dermacentor silvarum of Genus Dermacentor,Ixodes persulcatus of Genus Ixodes and Haemaphysalis concinna,and Haemaphysalis japonicas of Genus Haemaphysalis.Among them,625 Dermacentor silvarum(47.86 %),332 Ixodes persulcatus(25.42 %),308 Haemaphysalis concinna(23.58 %),41 Haemaphysalis japonica(3.14 %).were recorded.2.Diverse pathogens detectionAmong 1306 tick samples,1 Babesia,528 spotted fever group rickettsia,11 Bartonella,31 Anaplasma phagocytophilum,11 Borrelia burgdorferi was detected and the infection rates were 0.8 ‰,404.3 ‰,8.4 ‰,23.7 ‰ and 8.4 ‰ respecitvely.A total of 8 pathogens were identified as Borrelia afzelii,Borrelia garinii,Babesia spp.,Rickettsia raoultii,Candidatus Rickettsia tarasevichiae,Rickettsia heilongjiangensis,Bartonella spp.,Anaplasma phagocytophilum.Among the 8 pathogenic agents,there were at least two species of Lyme spirochetes(Borrelia garinii,Borrelia afzelii)and three species of spotted fever group rickettsia(Rickettsia raoultii,Candidatus Rickettsia tarasevichiae,Rickettsia heilongjiangensis)in the Heilongjiang ports.3.Coinfection of tick brone pathogensThe presence of coinfection among Anaplasma phagocytophilum,Babesia spp.and Bartonella spp.,Spotted fever group rickettsia were found in 24 tick samples.Conclusion:The single or multiple infection of various pathogens in the tick samples indicate the health risk in the areas surveyed,more attentions should be paid to the complication and plascity of the tick brone infections on clinical symptoms,diagnosis and subsequent treatment techniques.More retional prevention and control measures of tick caused infections should be developed in the future.