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@#Abstract: Objective To understand the phenotypic and genetic characteristics of Yersinia pestis strains isolated from Himalayan marmot natural focus area and domestic rat plague focus area in southern China, and provide reference for mastering the pathogenic characteristics of Yersinia pestis of two plague foci. Methods A total of 412 of Yersinia pestis strains isolated from Himalayan marmot plague focus and domestic rat plague focus of southern China were subjected to to sorbitol fermentation assays, virulence factor, different region (DFR) typing, and clustered regularly interspaced palindromic repeats (CRISPR) typing. Results The biochemical types of Y. pestis from the two plague foci showed distinct regional distribution features. Five biochemical phenotypes were identified in Yersinia pestis isolated from Himalayan marmot natural focus area, while only one biochemical phenotype was identified in strains isolated from the domestic rat plague focus of Southern China. Most of the Yersinia pestis isolated from the two plague foci were capable of producing the virulence factors of Fl and PstI. Among the strains from Himalayan marmot focus, 70.53% (201/285) were VW-positive, 75.09% (214/285) were Pgm-positive, 20.00% (57/285) of the strains were Pgm-negative, and 5.26% (15/285) were Pgm mixed-type strains. Among strains from domestic rat plague focus of southern China, 37.80% (48/127) were VW-positive, 29.13% (37/127) were Pgm-positive, 58.27% (74/127) were Pgm-negative, and 12.60% (16/127) were Pgm mixed-type strains. DFR typing revealed 22 genotypes of Y. pestis from the Himalayan marmot plague focus, with the main genotypes being type 5, 7, 8, 10, 19, 32 and 49. All strains from domestic rat plague focus area in southern China belonged to type 9. CRISPR typing revealed that all strains from the Himalayan marmot natural focus were classified into 7 CRISPR gene clusters and 14 CRISPR genotypes, with the main genotypes being G7, G22, G26-a1'and G22-A1'. All strains from domestic rat plague focus area in southern China belonged to CRISPR genotype G30, with the gene cluster being Ca8. Conclusions The phenotypes and genotypes of the Yersinia pestis of Himalayan marmot plague focus are diverse, with an obvious characteristics of geographical distribution. The phenotype and genotype of the Yersinia pestis of domestic rat plague focus of Southern China are single. DFR and CRISPR genotyping methods with phenotypic characteristics can effectively identify the Yersinia pestis isolated from the two plague foci, thereby meeting the needs of identification and traceability research.
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Objective:To observe multiple locus variable-number tandem repeat analysis (MLVA) typing of Brucella isolated from Himalayan marmot in Qinghai-Tibet Plateau of Qinghai Province, and to explore the relationship between the strains and strains previous isolated from Qinghai Province. Methods:Blood samples of Himalayan marmot were collected in Qinghai-Tibet Plateau of Qinghai Province from March 2019 to October 2020. Pathogens were isolated and cultured from Brucella antibody positive samples identified by using the rose bengal test (RBT). Conventional biological methods and molecular biological methods (BCSP31-PCR and AMOS-PCR) were used for strain identification. At the same time, MLVA method was used to genotype the isolated strains, and cluster analysis was used to analyze the genetic relationships between the strains based on the genotype of 70 Brucella isolated from different hosts in Qinghai Province. Results:A total of 1 466 blood samples of Himalayan marmot were collected from Qinghai-Tibet Plateau. Two strains of Brucella were isolated and cultured from 64 RBT-positive samples, named QH2013054 and QH2013062, respectively. They were identified as Brucella ovis biotype Ⅲ by conventional and molecular biological methods. The MLVA genotyping results showed that QH2013054 and QH2013062 were different at the Bru16 locus, indicating different MLVA genotypes. Cluster analysis showed that strain QH2013054 had the same MLVA genotype as 7 strains, among which 6 strains were from 3 farmers and 3 sheep from the same family in Gonghe County, and 1 strain was from a farmer in Menyuan Hui Autonomous County. The strain QH2013062 had the same MLVA genotype as 4 strains, including 3 strains from 3 farmers in Menyuan Hui Autonomous County and 1 strain from a farmer in Tu Autonomous County of Huzhu. Conclusions:The strains of Brucella isolated from Himalayan marmot in Qinghai-Tibet Plateau of Qinghai Province have the same MLVA genotype as some strains of Brucella isolated from humans and sheep in Qinghai Province. It is speculated that the host humans, sheep and Himalayan marmot in Qinghai-Tibet Plateau may have a common source of infection.
ABSTRACT
Qinghai-Tibet Plateau is one of the major plague foci in China. Himalayan marmot (hereinafter referred to as the marmot) is the main host animals of the foci. Effective identification and monitoring of its habitat in Qinghai-Tibet Plateau is important for active prevention and effective control of the marmot plague epidemic. Spatial information technology is an important means for rapid identification and effective monitoring of marmot. This review analyzed the factors that affect the distribution patterns of marmot habitat, including topographical features, soil properties, vegetation types and cover, climatic conditions and human activities, and reviewed and summarized the progress and shortcomings of relevant research on identifying and monitoring marmot habitat based on spatial information technologies such as remote sensing and geographic information system. Meanwhile, combined with the emerging low-altitude remote sensing, crowdsource data acquisition, machine learning and other big data mining methods, from the perspective of multi-source data, integration of emerging technologies and comprehensive evaluation system, the new ideas of using spatial information technology to quickly identify and effectively monitor the habitat of marmot, was discussed. It is expected to provide technical support for prediction and effective control of marmot plague in Qinghai-Tibet Plateau under the background of changing global climate and increasing human activities.
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Objective To analyze the ecological environmental differences of hibernation hole and temporary hole of Himalayan marmot based on global positioning system (GPS),remote sensing (RS) and geographical information system (GIS) in Yushu City,Qinghai Province.Methods Hibernation holes and temporary holes were located based on GPS.Ecological environment factors related with Himalayan marmot,such as land surface temperature (LST),digital elevation model (DEM),normalized different vegetation index (NDVI),were extracted based on RS and GIS.The ecological environment differences between hibernation hole and temporary hole were explored based on epidemiological statistical method.Results Monthly LST (degree Kelvin,K) of hibernation hole was slightly higher than that of temporary hole in the same period.Yearly day LST of hibernation hole was 1.1 K higher than that of temporary hole in the same period.Yearly night LST of hibernation hole was 0.3 K higher than that of temporary hole in the same period.Monthly NDVI of temporary hole was slightly higher than that of hibernation hole in the same period.Yearly NDVI of temporary hole was 0.001 higher than that of hibernation hole in the same period.DEM of temporary hole was about 40 m higher than that of hibernation hole.The top two ratios of soil type factors were both alpine meadow soil and dark felty soil for hibernation hole and temporary hole,which were 62.1％ and 29.3％,64.4％ and 25.6％.The top two ratios of land cover factors were both rainfed cropland and mosaic cropland for hibernation hole and temporary hole,which were 43.3％ and 25.8％,40.0％ and 26.2％.Conclusions Soil type factors and land cover factors for hibernation hole and temporary hole are similar.Lower DEM and higher LST are chose for hibernation hole,and better NDVI is chose for temporary hole,which is good for food intake.