Survey On Ticks Species Distribution And Molecular Epidemiology Of Three Associated Tick-borne Microorganism In Jilin And Heilongjiang Province

Ticks,belonging to arthropods,are second only to mosquitoes as transmitting vector.More than 200 kinds of pathogen can be transmitted by ticks,which seriously affected human health and animal husbandry.Ticks were widely distributed in the northeast of China.With the changes of climate and environment,the incidence of tick borne diseases is rising in northeastern China.Therefore,it is of very practical significance to perform a study on ticks and tick-borne diseases in this area.In this study,ticks were collected by flagging vegetable.These species were identified by both morphological and molecular biology methods.Prevalences of tick-borne Rickettsia specie,Anaplasma species and Ehrlichia species were obtained by molecular biological methods.The results laid the foundations for the prevention and control of tick-borne diseases in northeastern China.Tick species in Jilin and Heilongjiang provinces.2928 ticks were collected by flagging vegetable in 9 cities located in Yanji City,Dunhua City,Jiaohe City of Jilin and Jiamusi City,Shuangyashan City,Yichun City,Suifenhe City,Hulin City and Tongjiang City of Heilongjiang provinces in China.Tick species of these arthropods were identified based on morphological and molecular rules.Dermacentor silvarum(n = 204),Dermacentor nuttalli(n = 253),Haemaphysalis longicornis(n = 390),Haemaphysalis concinna(n = 412),Ixodes persulcatus(n = 1699)ticks were acquired from Jilin and Heilongjiang provinces;I.persulcatus was dominant tick species in both Jilin and Heilongjiang provinces.The ratio of I.persulcatus were 38.6% and 66.8% in Jilin and Heilongjiang province respectively.There was no H.concinna in Jilin province,however,H.concinna was second most tick species in Heilongjiang province,with the ratio of 21.6%.Infection rates of Rickettsia spp.,Anaplasma spp.,Ehrlichia spp.in ticks.The ticks were amplified by PCR,cloned,sequenced,analyzed of homology and phylogenetic tree.In Jilin province,the positive rate of Rickettsia spp.,Anaplasma spp.and Ehrlichia spp.were respectively 3.8%,4.5%,1.5%.In Heilongjiang province,the positive rate of Rickettsia spp.,Anaplasma spp.and Ehrlichia spp.were respectively 7.7%,7.5%,2.0 %.The overall infection rate of tick-borne diseases in Heilongjiang province was higher than that in Jilin province.The positive rate of Rickettsia spp.were respectively 6.1%、7.5%、3.9%、5.5%、6.5% in D.silvarum,D.nuttalli,H.longicornis,H.concinna and I.persulcatus.The positive rate of Anaplasma spp.were respectively 2.3%、1.7%、3.5%、7.2%、9.4% in D.silvarum,D.nuttalli,H.longicornis,H.concinna and I.persulcatus.The positive rate of Ehrlichia spp.were respectively 0.8%、0.7%、3.1% in H.longicornis,H.concinna and I.persulcatus.Phylogenetic analyses showed that there were three Rickettsia spp.,two Anaplasma spp.,two determined Ehrlichia spp.in both Jilin and Heilongjiang province.One potential new species(Candidatus Rickettsia jingxinensis)was found in Jilin province and one Ehrlichia variant(Ehrlichia sp.hc-hlj209)was found in Heilongjiang province.