Objective To identify Yersinia pestis from the Mongolian gerbils and EV76 bacteria of plague by different region (DFR) fragment genotyping. Methods The DNA of 6 strains of Y. pestis and EV76 isolates was extracted by boiling method from Hangjinqi of Inner Mongolia in 2015, Yinchuan city of Ningxia Hui Autonomous Region in 2013, and Kangbao county of Hebei province in 2003. The DFR primers according to a report were synthesized by biological company, then amplified by PCR, analyzed genotype through agarose gel electrophoresis. Results The DFR genotypes of Y. pestis from Mongolian gerbils were G11, G17, and G20. The absent points of G11 were DFR01, 06, 07, 13, 15, 16, and 17; DFR18 was also absent for G17 in addition to the above; The absent point of G20 also included DFR12 in addition to G17. The absence DFRs of EV76 were 01, 02, 04, and 10. Conclusion Using the differential fragment genotyping method can quickly distinguish Y. pestis isolates from Mongolian gerbils and EV76. At the same time, it is possible to trace the source of the epidemic rapidly by identifying the genotype of wild strains.

Objective To understand the plague literacy status among residents in the plague foci in Hebei province, and provide scientific basis for the health education strategies of plague. Methods Two hundred and eighty residents over the age of 18 were selected randomly for questionnaire survey in two communities of Kangbao county; The χ ² test and Fisher's exact probability method were used to analyze the results. Results The overall level of health literacy related to plague of residents in Kangbao county was 32.26%. The percentages of residents who had the basic health knowledge and concept was 33.18%, healthy lifestyle and behavior was 52.53%, and health related skills was 11.06%. The differences of health literacy related to plague were statistically significant among residents in different sex groups ( χ ²=13.007, P<0.001), age groups ( χ ²=8.409, P=0.015), occupations groups ( χ ²=12.489, P=0.005), and level of education groups ( χ ²=44.717, P<0.001). Among them the women, over 60 years old, farmers, workers and low-education residents had low levels of health literacy. Conclusion In the future, we need to strengthen the health education of plague for the elderly, the workers and individuals withlower education level.

With the development of regional economy and the tourism in Zhangjiakou city, the way of health education for control of plague has changed. In this paper, using the predisposing, reinforcing, and enabling causes in educational diagnosis and evaluation (PRECEDE)model and the investigation data, combined with the related research results, a health education program was designed on controlling plague based on the sociology, epidemiology, behavioral diagnosis, and educational diagnosis, to establish suitable health education program of plague prevention in Zhangjiakou city.

Objective To investigation the plague health education methods and content to meet the need of different people in Kangbao county of Hebei province, and lay a solid foundation for targeted health education and achieve better results. Methods An anonymous questionnaire was conducted to investigate 387 residents in Kangbao county. Results The targeted group's lower rates of knowing were "the treatment of sudden high fever after contact the plague animals or bite with flea"(8.56%), "Kangbao county is the plague natural foci"(20.72%), and "the symptoms of the plague patients"(28.45%). Different occupations need different ways of plague health education(χ²=105.118, P<0.01). Correspondence analysis found that farmers and broadcast,students and lectures, workers and broadcast, cadres and the micro-channel all have strong correlations. The 76.14% of farmers choose broadcast, 66.30% of students choose lectures, and the doctors prefer brochure(37.10%) and TV(37.10%). In addition to the panels, newspapers and text message, the workers like other publicities. The leaders like the other publicities except the panels. Conclusion Use radio and television primarily to strengthen the propaganda for farmers. Organize more health education lectures in school for students. For workers and cadres, take a variety of ways of health education, for example, broadcasting, WeChat and text message. Doctors, considering the professional particularity, should be trained and assessed professionally to improve their emergency relief capability.

Objective To study the genotype and epidemiological characteristics of Yersinia pestis in Hebei foci. Methods Primers were designed according to the confirmed 22 different segments (DFR), to genotype the 116 Y. pestis DNA of Hebei province. Results All of the strains lack these DFR of 01, 06, 07, 13, 15-18, to compare the genetic typing system of DFR, Y. pestis from Hebei province belong to the 17 genotype, distributed in the northern Kangbao county neighboring Huade, Baiqi, and Taipusiqi in the Inner Mongolia Autonomous Region. Conclusion The Y. pestis is stable genetically in Hebei plague foci, and have only one genotype, so the epidemic tends to stabilize.

Objective To evaluate enzyme immunostaining technique for detection of F1 antigen of Yersinia pestis in rodents. Methods Visceral organ specimens of 266 mice infected with virulent Y. pestis and 207 control rodent specimens were detected by horseradish peroxidase labeled plague F1 monoclonal antibody (HRP-F1McAb) enzyme immunostaining technique, and in comparison with the RIHA and RGICA methods．Results Coincidence was 98.52% between HRP-F1McAb enzyme immunostaining technique and RIHA, Kappa=0.970, and the difference was statistically significant in the positive detection rates (χ²=5.140, P=0.016); Coincidence was 98.50% between HRP-F1McAb enzyme immunostaining technique and RGICA, Kappa=0.901, with statistically insignificant difference in the positive detection rates (χ²=0.250, P=0.625). Sensitivity of HRP-F1McAb enzyme immunostaining technique was 100%, specificity was 97.02%, positive predictive value was 97.14%, negative predictive value was 100%, and Youden index was 0.970． Conclusion The enzyme immunostaining technique is sensitive and specific, fast and simple in detection of plague F1 antigen. It is a valuable detection technique in early and rapid diagnosis of plague in rodents．

Objective To characterize the genosome of 116 Yersinia pestis strains isolated from plague foci in Hebei province in China. Methods All the strains were detected by polymerase chain reaction (PCR) with 15 pairs variable number tandem repeat (VNTR) provided by China CDC, then the length of results were analyzed. Results The numbers and lengths of the repeat sequences from all strains are same with the single primer, and different with the different primers, such as the length of all stains with the prime M52 is 153 bp, and the number of the repeat sequences is 3, then with the prime M59, the length and the number is 250 bp and 3 respectively. Conclusion Multiple loci VNTR analysis (MLVA) genetic typing is reliable, and it is stable genetic mark of Y. pestis from Hebei province. To build the database of the plague with MLVA is useful for the investigation of the plague variation and source.

Objective To investigate the species, composition and infection with Yersinia pestis of parasitical fleas on Myospalax aspalax bodies and their role in the epidemic of rodent plague in Hebei province, providing a scientific basis for the better control of rodent plague. Methods Parasitical fleas on the bodies of M. aspalax were collected and classified with Y. pestis isolated. Results Nine species of fleas belonging to 7 genera and 3 families were found in the present study. No Y. pestis was isolated from the 111 M. aspalax and the cultures of 715 fleas in 68 groups by microbiological tests, with the Y. pestis specific antibody negative in 88 serum samples from M. aspalax. Conclusion There are a great number of fleas on the body of M. aspalax that can be infected with Y. pestis naturally, with Amphipsylla daea being the dominant parasitical flea, which may be involved in plague epidemics.

【Abstract】 Objective To study  the  practicability  of  double  antigens  sandwich  enzyme  linked  immunosorbent  assay（DAgS?ELISA）on the detection of Yersinia pestis F1 antibodies. Methods A total of 558 samples antibodies of anti?F1 antigen were detected by DAgS?ELISA and trace indirect hemagglutination assay (trace?IHA). Results Thirty three samples were positive tested by IHA, 31 positive by DAgS?ELISA, the positive accordance rate was 90.91%, 99.81% for negative accordance rate, 99.28% for the total accordance rate. The positive rate detected by IHA and DAgS?ELISA were 5.91% and 5.56% respectively, and no statistics difference was found (χ2＝0.25，P＝0.625). About 27 the immuno?serum were positive detected by IHA and DAgS?ELISA methods, and the sensitivity of IHA test were all higher than that of DAgS?ELISA (t＝3.023, P＝0.006). Conclusion Sensitivity of DAgS?ELISA is lower than that of trace?IHA, but its specificity is better and no primary inhibitory phenomena, and could exempt from leak detection in the preliminary screening.

Objective To study the sensitivity of colloidal gold immunobinding and analyze the distribution of crowd bubonic plague F1 immune body in Hebei province.Methods 196 serums and 162 serums of healthy people were sampled from history areas affected by plague and plague foci among animals(Zhangjiakou city) in Hebei natural plague foci and fur processing workers in Baoding.100 serums were collected from non-plague foci as control.Colloedal gold immunobinding and indirect hemagglutination test(IHA) were used to detect,at the same time,the minimum limit of detection of these two methods was compared.Results There were 3 positive serums in 196 serum samples,and the positive rate was 1.53%.None positive samples was found in 162 serum samples.The control were all negative.Conclusion The minimum detection of colloedal gold immunobinding was less than that of IHA.There were positive serum samples in plague natural foci,and the people age whose serum presented positive exceeded 40 years old.The samples collected from Baoding fur processing workers and non-plague foci were all negative.2 samples were positive after vaccination by investigation,and others needed be further explored.

Objective To study the three-dimensional distribution and maintenance mechanisms of plague F1 antibody of healthy population in the plague natural foci of Hebei province. Methods To sample 196 blood samples from three administrative villages belonging to plague natural foci formerly, and collect 100 blood samples from non-infected areas as the control. Indirect hemagglutination test(IHA) and colloedal gold immunobinding were used in this test. Results There were 4 positive among 196 blood samples, and the positive rate was 2.04%. There were 4 positive samples in IHA and 3 positive samples in colloedal gold immunobinding. The human serums collected from non-infected areas were all negative after tested by theses two methods. There was significant difference between the positive rate of F1 antibody in epidemic areas and the positive rate of F1 antibody in non-epidemic areas ( χ ₂=0.822, P<0.05). Conclusion At present, there are still a number of F1 antibody positive population in the natural epidemic focus of Hebei, and it needs further investigation and analysis to clarify.

Objective Plague animal material is tested by 4-pair-primer-PCR which is compaired with traditional “4 piece test” to find a quick diagnostic way for plague. Methods Narcotics test and 4-pair-primer-PCR are both done in traditional way. Results 52 positive specimen of 4-pair-primer-PCR are found from 150,and 62 of traditional way are found. Both the ways have no discrepancy( χ ²=1.42, P> 0.05 ). Conclusion 4-pair-primer-PCR is a quick,peculiar,sensitive method for the diagnosis and surveillance of plague.