Isolation And Identification Of Tick-derived Lymphocytic Choriomeningitis Virus And Tick Bome Encephalitis Virus

Ticks can transmit a variety of zoonotic diseases,such as Lyme disease,Tick-borne encephalitis.Tick was first identified as a new vector of Lymphocytic ch-oriomeningitis virus(LCMV)in 2018.LCMV is popular in Jilin Province,Inner Mongolia Autonomous Region and other places in China.Rodents are the natural hosts for LCMV.Human infection with LCMV can appear fever,fatigue,meningitis and other symptoms,for severe cases can lead to death,pregnant women infection can make the baby abortion.Tick Bome Encephalitis virus(TBEV)is mainly transmitted by Ixodes persulcatu.After the person is infected,the expression often has a headache,quadriplegic and so on.Northeast China is one of the main natural epidemic focus of TBEV.In recent years,with the change of ecological environment and tick species distribution,the prevalence trend of TBEV has also changed.In order to understand the prevalence of LCMV and TBEV in Northeast China,the following studies were conducted:(1)From April-June 2019 and April-June 2020,a total of 955 ticks were collected in Yakeshi City,Zhalantun City,Arshan City,Oroqen Autonomous Banner of Inner Mongolia and Dunhua City,Huadian City,Baishan City,Tonghua County of Jilin.Among them,Dermacentor nuttalli,Ixodes persulcatu,Dermacentor silvarum,Haemaphysalis japonica and Haemaphysalis longicorni were identified by morphological and molecular biology.(2)Isolation and identification of lymphocytic choriomeningitis virus:Semi-nested PCR primers were designed and the target fragment of 248bp could be amplified,and the minimum gene of 0.45×10~2 copies/?L could be detected.Using this method,LCMV was detected in all species of ticks.There was no significant difference between tick species and total positive rate was 11.51%.Two LCMV strain were isolated with BHK-21 cells,and the whole genome sequence was obtained.Genetic evolution analysis results show that the two strains LCMV all belong to LCMV type?.It was in the same evolutionary clade as DH46 strain isolated from Dunhua City of Jilin in China.(3)Isolation and identification of tick bome encephalitis virus:Semi-nested PCR primers were designed and the target fragment of 350bp could be amplified,the minimum gene of 0.14×10~3 copies/?L could be detected.Using this method,TBEV was detected only in Ixodes persulcatu,Dermacentor nuttalli,Haemaphysalis japonica of Jilin.The total positive rate was0.84%.One TBEV strain was isolated with BHK-21 cells,and the whole genome sequence was obtained.Genetic evolution analysis results show that the strains of TBEV belong to far-eastern subtype.It was in the same evolutionary clade as JL-jiaohe strain isolated from jiaohe City of Jilin in China.There were 82 amino acid variation sites compared with that of sengzhang strain.