Objective To identify rodent residues using DNA barcoding technology in plague areas of Shaanxi and to analyze the feasibility of DNA barcoding method.Methods DNA extraction,PCR,electrophoresis and sequence determination and alignment were used to determine the cytochrome C oxidase Ⅰ (COI) gene sequence from 62 residues of 7 species identified by morphology in 8 different parts.COI gene sequence was analyzed using BLAST software of American National Center for Biotechnology Information (NCBI) for sequence homology comparison and the phylogenetic tree was constructed by using the neighbor joining(NJ)method of COI gene sequence.Results In addition to the hair,CO I genes of the feet,the tail,the fur,the muscle,the ribs,the ear,and the eye were amplified,respectively,and the size of amplified fragment was similar to the size of the product with an expected fragment(700 bp),and the fragment was a single band.COI genes of 59 residue specimen were obtained by DNA sequencing and there were high degree of homologies between CO I gene sequences of Meriones unguiculatus,Cricetulus barabensis,Meriones meridianus,Dipus sagitta,Phodopus roborovskii,Rattus norvegicus and Allactaga sibirica and their corresponding host genes in NCBI(99.0％,98.1％,99.8％,98.9％,99.5％,99.1％,98.3％).NJ method showed that 7 NJ phylogenetic trees were constructed with COI sequence of 59 species residues.The CO I sequences of same rodent with different residues were clustered into one group.Condusion DNA barcoding technology can identify host animal residues in plague areas,and the identification results are reliable.

Objective To apply DNA barcoding technology for exploring its taxonomic status and differences in the molecular biology of Cricetulus barabensis in Shaanxi Province.Methods Sixty-five samples of Cricetulus barabensis were collected from Dingbian,Jingbian Counties in northern of Shaanxi and Dali County in Guanzhong plain (Dingbian 58 samples,Jingbian 2 samples,and Dali 5 samples).According to the mitochondrial cytochrome C oxidase subunit I gene (CO I) sequence,the genetic distance was calculated and Neighbor-Joining tree was constructed.Results The genetic distance between two samples (13.16,13.21) and other 56 samples of Dingbian was 9.2％-10.0％.The genetic distance between the 56 samples of Dingbian and Jingbian was less than 1％ and Dali was 7.2％-8.3％;the average intraspecific genetic distance of Jingbian and Dali was less than 1％.The Neighbor-Joining tree showed that all the Cricetulus barabensis samples from the three counties were separated into two large branches.The samples of 13.16,13.21 from Dingbian together were classified into a class and the rest of the samples into another separate branch.At the same time,other samples from Dingbian except 13.16,13.21 and Jingbian were distributed in a small branch,and Dali samples were occupied another small branch.Conclusion Using the DNA barcoding technology,we have determined three subspecies of Cricetulus barabensis in Shaanxi Province,Dingbian has two kinds and Dali has a different subspecies.

We studied the genetic characteristics of Spermophilus in Shaanxi Province,China.The COI,Cyt-b gene were sequenced and the results were compared with those of dauricus from Inner Mongolia Keyouzhong Banner and Zhengxiangbai Banner,and S.alaschanicus from Haiyuan County of Ningxia.And genetic distance was analyzed and Neighbor-Joining tree was built.Results showed that the genetic distance of COI gene sequences between Spermophilus from Dingbian County in Shaanxi and S.alaschanicus in Ningxia was ≤0.5％,and the genetic distance was ranged from 7.9％ to 9.3％ with Citellus dauricus from Inner Mongolia.The genetic distance of Cyt-b gene between Spermophilus from Dingbian County in Shaanxi and S.alaschanicus in Ningxia was ≤2.2％,and ranged from 8.9％ to 11.2％ with Citellus dauricus from Inner Mongolia.The Neighbor-Joining tree of COI,Cyt-b gene showed two major clusters.One of them were clustered by Spermophilus from Dingbian County in Shaanxi and S.alaschanicus in Ningxia,and another one was Citellus dauricus from Inner Mongolia.The Neighbor-Joining tree of COI gene showed that all samples from Shaanxi Province clustered in a group.In conclusion,the Spermophilus in Shaanxi Province were S.alaschanicus.

Objective:To analyze the epidemiological characteristics of public health emergencies caused by human brucellosis in Shaanxi Province in 2020, and to provide scientific basis for prevention and control of human brucellosis in Shaanxi Province.Methods:Descriptive epidemiological analysis of public health emergencies caused by human brucellosis in Shaanxi Province in 2020 was carried out, and the handling of the epidemic was studied.Results:A total of 13 public health emergencies caused by human brucellosis were reported in Shaanxi Province in 2020, 3 in northern Shaanxi, 10 in Guanzhong area, involving 65 confirmed cases of human brucellosis. Gender distribution: 47 males and 18 females; occupational distribution: 35 farmers, 13 breeders, 8 students, 6 scattered children, 2 workers, and 1 child in kindergarten; age distribution: the age of onset was mainly 50 to 69 years old (30 cases); time distribution: 13 public health emergencies occurred in April to August, with the peak in May; route of infection: 11 cases were infected by occupational exposure, 1 case was infected by drinking raw goat milk, and 1 case was infected by contacting the dogs infected by sick sheep. And 13 public health emergencies were handled in a timely and effective manner, including incident reporting, epidemiological investigation, high-risk population screening, pathogen cultivation, animal epidemic disposal, disinfection, publicity and education, etc.Conclusion:The brucellosis epidemic is active in the old epidemic areas in northern Shaanxi and the new epidemic areas in Guanzhong area, Shaanxi Province, and targeted prevention and control measures should be formulated according to the epidemiological characteristics of the epidemic to ensure accurate prevention and control of human brucellosis.

Objective:To construct a follow-up evaluation index system for "Diagnosis of Brucellosis" (WS 269-2019), and provide a reference basis for the next revision and improvement of the standard.Methods:The evaluation index system for "Diagnosis of Brucellosis" (WS 269-2019) was preliminarily established by consulting relevant references and materials. The experts in the field of diagnosis, treatment, prevention and control of brucellosis were selected, and two rounds of expert consultation were carried out in the form of questionnaires using the Delphi method. The necessity and availability of evaluation indicators were scored, and suggestions for modifying and adding indicators were put forward. Based on this, a standard follow-up evaluation index system was established. At the same time, a judgment matrix was constructed combined with the Saaty scale, and the analytic hierarchy process was used to calculate the weight of each index in the system.Results:After 2 rounds of expert ( n = 10) consultation, a standard follow-up evaluation index system for "Diagnosis of Brucellosis" (WS 269-2019) was constructed with 3 first-level indexes, 8 second-level indexes and 21 third-level indexes. The positive coefficients of experts in 2 rounds of questionnaires were both 100%; the coefficient of authority of experts was 0.82; the Kendall's coefficients of concordance of first-level, second-level and third-level indexes were 0.722, 0.260, and 0.181, respectively, with P < 0.05. Among the first-level indexes, the weight of standard quality evaluation was the highest (0.364), and the weight of standard implementation status was the lowest (0.278); among the second-level indexes, the combined weight of social benefits was the highest (0.186), and the combined weight of advanced nature was the lowest (0.043); among the third-level indexes, the combined weight of timely diagnosis rate was the highest (0.096), and the combined weight of consistency with technical data was the lowest (0.009). Conclusions:The constructed follow-up evaluation index system for "Diagnosis of Brucellosis" (WS 269-2019) is scientific and reliable, which evaluated qualitatively and quantitatively, reduces the defects of a single evaluation, and provides a basis for subsequent revision and improvement of the standard.

Objective:To analyze the epidemiological characteristics and related indicators of plague in Yulin City, Shaanxi Province, and to evaluate the risk of plague epidemic in the future and formulate scientific and reasonable prevention and control measures.Methods:The plague surveillance data of national (Dingbian County) and provincial (Yuyang District, Jingbian County, Hengshan District, Shenmu City, Fugu County) plague monitoring sites in Yulin City from 2011 to 2021 were collected through the China Disease Prevention and Control Information System Pestis Prevention and Control Management Information System, and the plague epidemic situation among humans and animals, the main host animals and their flea infection were analyzed by descriptive epidemiological methods. The expert consultation method and plague risk assessment tool V1.0 were used to assess the epidemic risk of the plague in Yulin City.Results:There was no human and animal plague epidemic in Yulin City from 2011 to 2021. In national monitoring site, the density of main host animal was 5.79/hm 2, ranging from 3.02/hm 2 to 9.08/hm 2,the dominant species was Mongolian gerbil, accounting for 98.21% (3 402/3 464); the capture rate of wild nocturnal rodents was 1.27% (350/27 600), ranging from 0.21% to 3.83%, the dominant species was Cricetulus barabensis, accounting for 44.86% (157/350); the flea infection rate of the rodent body was 16.91% (768/4 541), with a flea index of 0.40, the dominant flea species was the Nosopsyllus laeviceps kuzenkov, accounting for 66.54% (1 203/1 808). In provincial monitoring site, the density of main host animals was 0.49/hm 2, ranging from 0.31/hm 2 to 0.67/hm 2, the dominant species was Alashan ground squirrel, accounting for 63.61% (194/305); the capture rate of nocturnal rodents in the wild was 1.76% (560/31 795), ranging from 0.89% to 3.93%, the dominant species was Roborovski dwarf hamster, accounting for 26.61% (149/560); the capture rate of domestic rats was 2.37% (397/16 750), ranging from 1.48% to 3.10%, the rodents included Rattus norvegicus (47.36%, 188/397) and house mouse (52.64%, 209/397); the flea infection rate of the rat body was 13.26% (182/1 373), with a flea index of 0.40; the dominant flea species was Ophthalmopsylla jettmari, accounting for 45.23% (251/555). The 5 281 pathogenic culture samples and 2 110 serological test samples were all negative. The Pearson correlation analysis results showed that there was no correlation between rodent density and flea infection rate or flea index at national and provincial monitoring sites ( r = - 0.26, - 0.48, 0.09, 0.12, P > 0.05), while flea infection rate and flea index were positively correlated ( r = 0.67, 0.81, P < 0.05). In 2022, Yulin City, Shaanxi Province was not ruled out the possibility of human plague epidemic, and the risk of plague epidemic among animals was high. Conclusions:From 2011 to 2021, the density of the main host animals at the national and provincial monitoring sites in Yulin City has remained at a low level, and the flea index has increased. There is a risk of plague epidemic in Yulin City, so the monitoring work should be further strengthened, and emergency supplies and capacity reserves should be well prepared.

Objective:To investigate the pathogenic and epidemiological characteristics of human brucellosis in Shaanxi Province, and to provide a basis for scientific prevention and control of human brucellosis in Shaanxi Province.Methods:The pathogenic culture data of 507 reported cases of human brucellosis reported in Shaanxi Province from 2014 to 2021 were collected from the Shaanxi Provincial Center for Disease Control and Prevention. The epidemiological data of the cases were collected from the Infectious Disease Information Reporting Management System of China Disease Prevention and Control Information System. The data were summarized and analyzed using Excel 2016 software, and visualized using ArcGIS 10.6 software.Results:The 507 cases were concentrated from 2018 to 2021 (322 cases), with a peak incidence period from May to July (255 cases). Cases mainly distributed in Weinan City (129 cases), Yulin City (114 cases) and Yan'an City (97 cases). Farmers were the main occupation (415 cases). The cases were mainly aged 40 - 59 (272 cases). The male to female gender ratio was 3.22 ∶ 1.00 (387 ∶ 120). Totally 95.46% (484/507) of the cases had a history of close contact with cattle or sheep, mainly sheep (480 cases). The clinical symptoms included fever, fatigue, hyperhidrosis, joint and muscle pain, with rare liver, spleen and testicular enlargement. Totally 89.55% (454/507) of the cases were diagnosed during the acute phase. In vitro agglutination test, 1 ∶ 200 positive cases were the most common (139 cases). Totally 214 strains of Brucella were isolated and cultured, and the rate of bacterial production was 42.21%, all of which were Brucella melitensis, of which type 3 accounted for 79.91% (171/214). Conclusion:Human brucellosis cases in Shaanxi Province are mainly infected by contact with sheep, with the main source of infection being Brucella melitensis type 3.

Objective To apply the DNA barcoding technology for identification on host animal and to establish the host animal DNA bar code database on natural foci of plague in Shaanxi.Methods 139 host animals belonging to 3 orders,6 families and 12 genera and 62 residues belonging to 7 species from 8 different parts of the province,were detected.DNA barcoding technology was used to analyze the DNA CO Ⅰ gene sequence on the natural foci of plague in Dingbian county.Results The intra-specific genetic distance was less than 2％ while the inter-specific distance ranged from 8.9％ to 15.1％.Fourteen major clusters were apparently showed on a Neighbor-Joining tree.Residue samples could be detected regarding the objective gene.Alashan ground squirrel was previously noticed to carry 14 major clusters,which were previously mistakenly named as Citellus dauricus in Dingbian county.Conclusion DNA barcoding technology could overcome the shortcomings caused by the morphological identification so could be used to identify the host animal and residues in the natural focus of plague.

Objective:To analyze the incidence of brucellosis and the genotypes of Brucella isolates or nucleic acids in Shaanxi Province, to get the epidemiological and molecular genetic characteristics, and to provide scientific basis for precise prevention and control of human brucellosis. Methods:Log into the Chinese Disease Control and Prevention Information System, collect the incidence data of human brucellosis of Shaanxi Province in 2020, and analyze the epidemiological characteristics. Bacteriology and PCR methods were used to identify the isolates or nucleic acids, and multiple locus variable-number tandem repeat analysis (MLVA) was used for molecular typing. BioNumerics (Version 7.6) software was used to analyze the results of MLVA.Results:In 2020, 1 086 cases of human brucellosis were reported in Shaanxi Province, the incidence rate was 2.80/100 000, involving 86 counties (districts), the epidemic peak was from March to September (865 cases), male-to-female ratio was 2.68 ∶ 1.00 (791 ∶ 295), 79.74% (866 cases) in the age group of 30 to 69 years old, and 83.43% (906 cases) of the cases were farmers. Biotype identification of 36 isolates showed that 4 isolates were mutant Brucella melitensis, 3 isolates were Brucella melitensis 1 and 29 isolates were Brucella melitensis 3. The 36 isolates and 7 nucleic acids were identified as Brucella by BCSP31-PCR and Brucella melitensis by AMOS-PCR. MLVA-16 genotyping, panel1 showed two genotypes: type 42 (1-5-3-13-2-2-3-2) and type 63 (1-5-3-13-2-3-3-2), panel2A showed 4-41-8 and panel2B showed high variability. Thirty-six isolates and 7 nucleic acids were divided into 33 genotypes, of which 27 genotypes were single isolates and 6 genotypes were shared. Conclusions:The situation of human brucellosis prevention and control in Shaanxi Province is grim. MLVA-16 is a mature genotyping method, which determines the existence of multiple genotypes of Brucella isolates or nucleic acids in Shaanxi Province, which can provide scientific information for precise prevention and control of human brucellosis, outbreak analysis and epidemiological traceability.

Objective:To understand the changes of brucellosis prevention and control knowledge awareness among breeders in Chunhua County, Xianyang City, Shaanxi Province before and after the publicity intervention.Methods:A multi-stage cluster sampling method was adopted to select 10 townships with more reported cases of human brucellosis in Chunhua County from January 2019 to June 2020, and each township was given priority to select the administrative village with the largest number of reported cases for investigation. At least 20 breeders aged 20 years old and over in each administrative village were selected, and if the number was insufficient, supplementary surveys would be conducted in other administrative villages with the larger number of breeders in the township. Questionnaire survey was conducted on all subjects, including general demographic characteristics, brucellosis prevention and control knowledge and related protective behaviors. After the baseline investigation, 6 months of brucellosis prevention and control knowledge publicity was carried out in the administrative villages included in the investigation, and the awareness rate of brucellosis prevention and control knowledge before and after the publicity intervention was compared to evaluate the effect of publicity intervention.Results:After the publicity intervention, a total of 240 breeders were investigated, and 176 people were aware of brucellosis prevention and control knowledge, with an overall awareness rate of 73.33% (176/240), which was significantly higher than that before the publicity intervention (57.50%, 115/200), and the difference was statistically significant (χ 2 = 12.21, P = 0.005). After the publicity intervention, the awareness rates of breeders on "can cattle and sheep transmit diseases to humans" and "do you know that cattle and sheep can only be purchased after passing the quarantine inspection" were relatively high, they were 95.83% (230/240) and 95.00% (228/240), respectively, and the differences were statistically significant (χ 2 = 50.04, 112.64, P < 0.001) compared with that before the publicity intervention [71.50% (143/200) and 51.00% (102/200)]. The awareness rate of breeders on "how brucellosis is transmitted from livestock to humans" was the lowest, it was 53.33% (128/240), which was not significantly different (χ 2 = 0.82, P = 0.370) from that before the publicity intervention (49.00%, 98/200). Conclusions:After the publicity intervention, the overall awareness rate of brucellosis prevention and control knowledge of breeders in Chunhua County has improved, but the awareness rate of some individual issues is still low. It is suggested to strengthen the pertinence of publicity and education.