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@#Abstract: Objective To conduct a molecular epidemiological tracing and analysis of Yersinia pestis strains isolated from two human plague outbreaks with unknown sources in Gansu Province, China. The results of this analysis would provide a basis for isolating and controlling the sources of Yersinia pestis. Methods The strains of Yersinia pestis isolated from two human plague outbreaks occurring on December 12, 2017, and September 27, 2019 were genotyped by the different region (DFR) and the clustered regularly interspaced short palindromic repeats (CRISPR). The repeat numbers of the variable number tandem repeat (VNTR) loci in the tested strains of Yersinia pestis were calculated by the multiple variable number tandem repeats analysis (MLVA), and the location of the phylogenetic tree of the tested strains was determined with the method of minimum spanning tree (MST) by the software BioNumerics 6.6. Results The strain of 20171212 lacked DFR01, DFR02, DFR03, DFR04, DFR13, DFR23, and the DFR type was identified as type 8. The space sequence of YPa was a1'-a2-a3-a4-a5-a6-a7-a35, the space sequence of YPb was b1-b2-b3-b4, the space sequence of YPc was c1-c2-c3, the gene cluster of CRISPR was Ca35', the genotype of CRISPR was 26'. MLVA clustering analysis showed that the strain clustered within in the cluster of Yuerhong pasture in Subei County and formed an independent branch. On the other hand, the strain of 20190927 lacked DFR01, DFR13 and DFR23, with the DFR type identified as type 1b. The space sequence of YPa was a1-a2-a3-a4-a5-a6-a7, the space sequence of YPb was b1-b2-b3-b4, the space sequence of YPc was c1-c2-c3, the gene cluster of CRSIPR was Ca7, the genotype of CRSIPR was 22 MLVA clustering analysis showed that the strain was located close to the cluster of Dangjinshan in Akesai County, and relatively distant from the cluster of Yuerhong pasture in Subei County. Conclusions The genotypes of strain 20171212 by DFR and CRISPR were consistent with the main genotypes of Y. pestis from Himalayana Marmota foci in Subei County, which confirmed that the human plague cases were naturally occurring locally. However, the strain gathered the cluster of Yuerhong pasture in Subei County, which indicated that the source of infection was not in Yanchiwan Town, but in the surrounding area of the Yuerhong pasture. The genotypes of strain 20190927 by DFR and CRISPR were in accordance with the main genotype of Y. pestis from Himalayana Marmota foci in Akesai County and were closer to the cluster of Dangjinshan in Aksai County than to
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Introduction: The Qinghai-Tibet Plateau is considered the most plague-heavy region in China, and skinning and eating marmots (Marmota himalayana) are understood to be the main exposure factors to plague. Yersinia pestis is relatively inactive during marmots' hibernation period. However, this case report shows plague infection risk is not reduced but rather increased during the marmot hibernation period if plague exposure is not brought under control. Case Presentation: The patient was a 45-year-old man who presented with high fever, swelling of axillary lymph nodes, and existing hand wounds on his right side. Y. pestis was isolated from his blood and lymphatic fluid. Hence, the patient was diagnosed with a confirmed case of bubonic plague. Later, his condition progressed to septicemic plague. Plague exposure through wounds and delays in appropriate treatment might have contributed to plague progression. Conclusion: This case report reveals that excavating a hibernating marmot is a significant transmission route of plague. Plague prevention and control measures are priority needs during the marmot hibernation period.
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Marmota , Yersinia pestis , Animales , China , Humanos , Masculino , Persona de Mediana EdadRESUMEN
OBJECTIVE: To study the genotype distributions and epidemiological characteristics of Yersinia pestis in Gansu province. METHODS: Primers were designed according to the confirmed 23 differential sections, to genotype the 202 Yersinia pestis DNA of Gansu province by PCR, and to analyze its distribution and epidemiological characteristics. RESULTS: Yersinia pestis in Gansu province could be divided into eight genotypes: 1b, 5, 7, 8, 13, 26, new genotype 1 (GS1) and new genotype 2 (GS2). They were distributed in various regions. 1b, 8 and GS1 genotypes of Yersinia pestis had been identified since 1960s but the 7, 13 and 26 genotypes had not been isolated for more than 40 years while GS2 and 5 genotypes had been isolated since 1990s. CONCLUSION: 1b, 8 and GS1 genotypes of Yersinia pestis continued to be violently prevalent since 1960s but 7, 13 and 26 genotypes had not been isolated for more than 40 years while GS2 and 5 genotypes had started to be popular since 1990s.