Objective To investigate the epidemiological characteristics and infection sources of human brucellosis in Qinghai province, China, 2017-2019, and to provide a scientific basis for the prevention and control of brucellosis. Methods The data of brucellosis cases in Qinghai province from 2017 to 2019 were collected, as reported by the China Information System for Disease Control and Prevention. The descriptive epidemiological method was used to analyze the epidemiological characteristics. The isolated bacteria were cultured and identified to analyze the etiological characteristics. Results From 2017 to 2019, a total of 301 brucellosis cases were reported in Qinghai province, with an incidence of 0.45/100 000 in 2017, 1.81/100 000 in 2018, and 2.72/100 000 in 2019, with a significant difference between different years (t=16.421, P<0.05). The 301 cases were distributed in 26 counties (cities, districts), among which the top three counties (cities, districts) were Menyuan county (137/301, 45.51%), Dulan county (30/301, 9.97%), and Haiyan county (25/301, 8.31%). The age of onset ranged from 14 to 78 years, and the ratio of males to females was 3.63:1. Among the 301 cases, the top three occupations were farmers (31.89%), herdsmen (25.58%), and animal epidemic prevention personnel (20.27%); the mode of infection included livestock fattening and selling (108/301, 35.88%), rearing (97/301, 32.23%), animal epidemic prevention (61/301, 20.27%), processing (26/301, 8.64%), and food-borne infection (9/301, 2.99%). From 2018 to 2019, 37 whole blood samples with positive Rose Bengal plate agglutination test, colloidal gold immunochromatographic assay, and serum agglutination test were cultured, and 8 suspected strains were obtained, with a culture rate of 21.62%. The 8 strains of Brucella were identified as B. melitensis (cluster Ⅲ). Conclusion Currently B. melitensis (cluster Ⅲ) is the main epidemic strain causing human brucellosis in Qinghai province. And the prevalence of brucellosis in Qinghai province is on the rise. It is suggested that relevant departments should strengthen the control of sources of infection and take health promotion and other prevention and control measures among the high-risk population to control the occurrence and epidemic of brucellosis.

Objective To investigate the molecular epidemiological characteristics of human brucellosis in Alxa league, Inner Mongolia autonomous region (Inner Mongolia), China. Methods The clinical isolates of suspected Brucella with a positive blood culture result during 2015 to 2019 were identified by conventional biological methods and multiplex PCR assay. The molecular epidemiological characteristics of Brucella were investigated using multiple-locus variable-number tandem repeat analysis (MLVA). Results Twenty-three suspected Brucella strains were isolated from the confirmed cases of brucellosis in Alxa league from 2015 to 2019, and were identified as B. melitensis biovar 3 using conventional biological methods and multiplex PCR assay. Among the 23 cases, herdsmen accounted for 30.43% (7/23) and farmers accounted for 39.13% (9/23), both of whom had a history of sheep contact. The positive rate of Brucella antibody in serum was 78.26% (18/23). The MLVA showed that the 23 strains had genotypes of the main epidemic B. melitensis strains in China. According to the three loci with differences, the strains isolated from Bayanmuren Sumu belonged mainly to one group, and the two strains from Jilantai town belonged to another group. The 23 strains were associated with the isolates from Ningxia, Liaoning, Shandong, Zhejiang, Shanghai, and Guangdong (provinces, autonomous regions, and municipalities directly under the central government), and were not associated with isolates from its neighboring province Gansu. Conclusion The Brucella strains from Alxa league, Inner Mongolia are consistent with the epidemic strains of brucellosis in China, and are associated with the isolates from Ningxia, Liaoning, Shandong, Zhejiang, Shanghai, and Guangdong (provinces, autonomous regions, and municipalities directly under the central government).

Objective To investigate the epidemic process and molecular and epidemiological characteristics of the brucellosis in Menyuan county, Qinghai province, China, in April 2018, and to provide a reference for handling related events. Methods An on-site epidemiological investigation of the epidemic situation was performed using serological test methods (serum tube agglutination test and complement fixation test) and blood culture. The molecular characteristics of the strains were analyzed by multiple loci VNTR analysis (MLVA). Meanwhile, analyses were performed using patients'medical record data and laboratory test results. Results Two patients were infected with brucellosis due to contact with sheep with contagious abortion, and were diagnosed based on the Diagnostic Criteria for Brucellosis (WS269-2007) with acute stage of brucellosis according to their history of epidemiological exposure, clinical symptoms and signs, and laboratory test results. The two strains were genotype 42 as revealed by MLVA-8, and MLVA-16 genotyping proved the two strains to be 100% homologous. Conclusion MLVA can be used to analyze the association between areas with epidemic or sporadic brucellosis, trace the source of infection, and provide reliable technical support for trans-regional tracking and prevention and control of brucellosis.

Objective To compare the phenol water method and the iTron kit in extracting lipopolysaccharides(LPS) from Brucella. Methods LPS were extracted from B. melitensis strain 16M using phenol water method and kit method. The purity and structure of LPS was compared by SDS-gel electrophoresis and silver stain. The activity of the extracted LPS was detected by limulus amebocyte lysate agglutination test, and the characteristics of the two methods were compared. Results LPS extracted from Brucella by both methods had a high purity. There was no significant difference in activity of LPS extracted by phenol water method and the iTron kit ( t'=1.270, P=0.332), which was (4.926±0.051) and (5.015±0.037) EU/ng, respectively. LPS extracted by phenol water method might lose some LPS at 17×10 ³ and 26×10 ³, while using the iTron kit we can get intact LPS in a convenient and safe way. Conclusion The iTron kit has advantages in extracting LPS from Brucella compared with the phenol water method.

Objective Three suspected brucellosis cases were investigated in Suizhou city of Hubei province, and three suspected Brucella strains were identified. Methods Field investigation was applied to finish Brucella epidemiological survey, used Brucella conventional appraisal classification method and the phage cracking test for testing. BCSP31-PCR method (Based on Brucella genus specific gene BCSP31 target gene detection method), AMOS-PCR (based on electrophoresis banding identify B. abortus biovar 1, 2, 4 of Brucella, B. melitensis, B. ovis and B. suis biovar 1) and Real-time PCR, three molecular classification method were compared. Results Three patients were infected by close contact with sick animals and their meat, conventional identification and a variety of polymerase chain reaction (PCR) had the same results, B. melitensis biovar 3. Conclusion Brucella melitensis biovar 3 was identified as the pathogen of the three cases from Suizhou city and cases were mainly caused by direct contact with sick animals and their meat.

Objective To explore the feasibility of dilution rose bengal plate agglutination test (RBPT) for the diagnosis of brucellosis. Methods Serum samples from 93 brucellosis patients who came from Inner Mongolia, China in 2013 were tested by both dilution RBPT and standard tube agglutination test (SAT). According to the correlation between the results of the two tests and using the results of SAT as criteria, the sensitivity and specificity of RBPT were analyzed at different dilutions as cut-off values to evaluate the diagnostic accuracy. Results The area under the receiver operating characteristic curve for dilution RBPT was 0.946. When taking1∶2 as the cut-off value, the Youden index was 0.893, the sensitivity was 89.30% , and the specificity was 100%; when taking1∶4 as the cut-off value, the Youden index was 0.631, the sensitivity was 63.10%, and the specificity was 100%; when taking1∶8 as the cut-off value, the Youden index was 0.571, the sensitivity was 57.14%, and the specificity was 100%; when taking1∶16 as the cut-off value, the Youden index was 0.191, the sensitivity was 19.05%, and the specificity was 100%. Conclusion Dilution RBPT has the highest diagnostic accuracy at a dilution of1∶2, which provides a reference for the diagnosis of brucellosis.

【Abstract】 Objective To study the method to identify Brucella suis biovar 1 wild strain and S2 vaccine strain.  Methods A total of 21 strains of B.suis biovar 1 wild strain were analyzed by AMOS-PCR, PFGE and multiple-locus variable-number tandem-repeat analysis (MLVA).   Results B.suis biovar 1 and S2 could be discriminated by MLVA Bru9 and Bru16. Conclusion The MLVA assay can be applied to identification of wild strains and vaccine strain and can be proposed to as a complement of classical biotyping methods.

Objective To study the fauna of Phaonia (Diptera) in China.Methods Using Zoogeography principle and method.Results There are 357 species of Phaoniain China. General situation,characters of the fauna are discussed. Conclusion There are 330 local species,and make up 92.4% of Phaonia known in China.Which means the abundance,complexity and diversity of Phaonia in China.