| ObjectiveTo investigate the infection status of Borrelia burgdorferi in population,ticks and rodents in Jinghong City,Yunnan Province,and analyze the genotype of the pathogens to determine whether there is a natural foci of Lyme disease in Jinghong City.MethodFrom 2018 to 2019,rodents were caught by snap trap and cage trap at 9 survey sites in Jingne,Menghan,Gasa and Mengyang,and the kidney and bladder tissues were taken after dissection.Ticks were collected with cloth flags or from the host animals at8 survey points in Jingne and Dadugang.Human serum was collected at 3 survey points in Jingne.One part of rodent and tick samples were inoculated in BSK-II medium for isolation and culture of Borrelia burgdorferi,the other part was used to extract DNA.The DNA samples were detected by quantitative real-time PCR for the specific rec A gene,and then the 5s?23s r RNA gene spacer was amplified by nested PCR.The positive products were sequenced for homology analysis.Human serum samples were detected for Lyme disease antibody by IFA and verified by WB.ResultA total of 82 rodents were captured,of which 81 Rattus flavipectus accounted for98.78%.1078 ticks were captured,all of which were Boophius microplus.232 samples of human serum were collected,and 44 people were bitten,the remaining is unknown.82 rodents and 878 ticks were isolated and cultured for Borrelia burgdorferi,but none was isolated.The positive rate of rodents was 3.66%(3/82)for the rec A gene by quantitative real-time PCR.There was no significant difference in the positive rate between male and female rats and between different sites too(?~2=0.000,P=1.000;P=0.386).The positive rate of Boophius microplus was 1.50%(3/200),which all originated from Yunpan village of Jingne.6 positive samples were amplified by Nested PCR and sequenced analysis of the 5s?23s r RNA gene spacer,the results showed that Borrelia garinii was found in 3 Boophius microplus,but not detected in rodents.The positive rate of human serum was 18.53%(43/232)and 12.07%(28/232)by IFA and WB.Among them,the positive rate of those who have been bitten by ticks was20.45%(9/44),and that of those who have not been bitten was 10.11%(19/188),but there was no significant difference between them(?~2=3.598,P=0.058).In addition,there was no statistically significant difference in infection rates among people of different genders and ages(?~2=2.279,P=0.131;?~2=4.110,P=0.250),but the difference of infection rate among different survey points was statistically significant(?~2=6.338,P=0.042).In 28 Ig G positive samples,13 specific bands appeared,with Osp B and Osp A appearing most frequently.In 7 Ig M positive samples,4 specific bands appeared,mainly Osp B and P83/100.And there were 1 to 6 protein bands with different permutations in each sample.ConclusionThere is natural foci of Lyme disease in Jinghong City,Yunnan Province.The population infection rate is high,and the Borrelia burgdorferi proteinogram is polymorphic in different population samples.Rattus flavipectus may be one of the important host of Lyme disease in this area,although the carrying rate is not high,it is a dominant species of rodent and it is most active in residential areas,which is a certain threat to the population.Boophius microplus carries Borrelia garinii and may be one of tthe main vector of Lyme disease in Jinghong City.Moreover,the clinical manifestations of Lyme disease are complex and atypical,which brings great difficulties to clinical diagnosis.Therefore,the cultivation of clinical thinking and laboratory testing are particularly important in clinical practice. |
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