Study on the effect of temperature on the risk of hand, foot and mouth disease in Chengdu / 公共卫生与预防医学

Objective To explore the effect of temperature on the risk of hand-foot-and-mouth disease (HFMD) and population susceptibility. Methods The data of HFMD cases in Chengdu from January 1, 2016 to October 31, 2022 were collected, and local meteorological data during the same period were also collected. Distributional lag nonlinear models were developed. The relative risk (RR) of morbidity at different temperatures and different lags was calculated. Differences in the relative risk levels of different populations were analyzed and compared. Results A total of 263 776 cases of HFDM were reported in Chengdu during the study period. The distribution of HFMD was periodic. For the overall population, the short-term average temperature and RR showed a “U”-shaped relationship. When the lag time was 0-7 days, the cumulative RR was 1.59 (95%CI: 1.18-2.14) at the average temperature of -0.5℃ and 2.16 (95%CI: 1.60-2.91) at the average temperature of 34.5℃. The RR values under high and low temperatures decreased with increasing lag period. When the lag time was extended, the average temperature and RR showed an inverted “U”-shaped relationship, with higher RR at moderate temperatures and increasing as the lag period increased. The results of the subgroups showed that the RR of onset among scattered children was higher at high and low temperatures. Conclusion The risk effect of temperature on the onset of HFMD in different populations is variable and changes with the lag period, and the prevention and control measures should be adjusted in a timely and targeted manner.

Prevalence trend of human brucellosis in Qinghai Province from 2000 to 2012 / 中华地方病学杂志

Objective By summing up monitoring data of human brucellosis in Qinghai Province from 2000 to 2012, to evaluate epidemiological dynamics and analyze prevalence trend. Method Monitoring data of human brucellosis in Qinghai Province from 2000 to 2012 were collected, epidemiological characteristics including prevalence condition, area and population distribution were analyzed by descriptive epidemiology method. Results Totally 38 578 persons were examined from 2000 to 2012. The number of persons infected with brucellosis was 1 209, the infection rate was 3.34%;the number of patients diagnosed with human brucellosis was 344, the prevalence rate was 0.89%. New cases had occurred since 2006, and there were 158 new cases diagnosed with brucellosis. The prevalence rates in cities and areas of agriculture and pasture were 2.93%(78/2 663), 1.18%(33/2 806) and 0.70%(233/33 109), respectively. The ages of developing brucellosis ranged from 10 to 72 years old. The prevalence rates of biological pharmaceutical producers and the herdsman were [18.13%(196/1 081)] and [6.13%(353/5 763)], respectively. The prevalence rate of human brucellosis in Han nation was the highest [4.61%(467/10 140)], followed by Tibet [3.60%(443/12 318)], Mongolia [2.53%(211/8 342)], Tu [2.22%(110/4 953)] and Hui [2.09%(59/2 825)], and the differences were statistically significant (χ2 = 102.493, P < 0.01). Conclusion The prevalence state of human brucellosis in Qinghai Province is in a increasing trend, and new cases are increasing.

Spatial distribution of brucellosis in Qinghai Province from 2011 to 2013 / 中华地方病学杂志

Objective To reflect the spatial distribution of brucellosis among 7 counties in Qinghai Province from 2011 to 2013 with Geographic Information System (GIS) map.Method Epidemiological situations were overlay analyzed in infectious rate and prevalence rate with QHEndemic-GIS and SPSS 17.0 by statistics and mapping.Results Brucellosis was detected in 7 counties through the spatial distribution map.The infectious rate and prevalence rate of brucellosis were showing a phenomenon of high and low alternation in 3 years;meanwhile the prevalence in Gonghe County showed an obviously upward trend with the rates of 0.50％ (1/201),1.50％ (3/200),and 3.73％ (9/241),respectively.Conclusions GIS could reflect the state of brucellosis infection directly and correctly.Prevalence of brucellosis in the 7 counties has showed a sporadic phenomenon,and the prevalence of brucellosis has covered a wide region and many populations are at risk of this disease.The prevalence has showed an up-ward trend in these regions,which provides a scientific basis for prevention and control of brucellosis in these key regions.

Study of the plasmid profiles and geographical distribution of Yersinia pestis in China / 中华预防医学杂志

<p><b>OBJECTIVE</b>To analyze the plasmid features and geographical distribution characteristics of Yersinia pestis of different plague foci in China.</p><p><b>METHODS</b>A total of 2 213 Yersinia pestis strains were colected from 11 Chinese plague foci separated during 1943 to 2012, and plasmid DNA according to alkali cracking method, and measured the relative molecular mass (Mr) of plasmid DNA based on the standard plasmid contrast method, then analyzed the plasmid profiles by agar gel electrophoresis.</p><p><b>RESULTS</b>A total of 2 213 strains had 16 kinds of plasmids with different Mr, including 4×10(6), 6×10(6), 7×10(6), 13×10(6), 16×10(6), 20×10(6), 22×10(6), 23×10(6), 27×10(6), 30×10(6), 36×10(6), 45×10(6), 52×10(6), 65×10(6), 72×10(6) and 90×10(6). Plasmid were classified into 26 kinds of plasmid profiles. A total of 2 213 Yersinia pestis strains contained 4 large plasmids, 52×10(6), 65×10(6), 72×10(6) and 90×10(6), whose ratio was 22.10% (589/2 213), 75.60% (1 672/2 213), 0.17% (4/2 213), 2.12% (47/2 213), respectively. Among which, strains with plasmid 52×10(6), 65×10(6), 90×10(6) distributed in Qinghai-Tibet plateau Himalayan Marmot natural plague foci, strains with 72×10(6) plasmid only distributed in Inner Mongolia Meriones unguiculatus natural plague foci and Junggar Basin R. opimus natural plague foci, and 65×10(6) plasmid distributed in all the other foci.</p><p><b>CONCLUSION</b>Strains in Chinese 11 plague foci contained 4 kinds of large plasmid, the Mr respectively were 52×10(6), 65×10(6), 72×10(6), 90×10(6), which were classified into 26 kinds of plasmid profiles with other plasmid. These plasmid profiles distributed in relatively independent epidemic focus.</p>

Regional genotyping and the geographical distribution regarding Yersinia pestis isolates in China / 中华流行病学杂志

<p><b>OBJECTIVE</b>To type Yersinia (Y.) pestis isolates under different regions (DFR) and to observe their geographical distributions in China.</p><p><b>METHODS</b>23 DFRs primers and PMT1 (plasmid) primer were used to verify the DFR genomovars of Y. pestiss strains from 11 plague foci in China. A total of 3 044 Y. pestis isolates were involved for analysis on DFR profiles with the characteristics of geographical distribution.</p><p><b>RESULTS</b>52 genomovars were verified in 3 044 Y. pestis strains in China in which 19 genomovars as major and 33 genomovars as minor genomovar. 21 new genomovars, namely genomovar 32 to genomovar 52 were described on the basis of 31 genomovars previously confirmed. Three new genomovars belonged to new major genomovars, namely Himalayan marmot natural plague foci of the Qinghai-Tibet plateau newly added genomovar 32 and genomovar 44 as major genomovars. Mongolian gerbil natural plague foci of Inner Mongolia plateau were newly added genomovar 50 as one of the major genomovars.</p><p><b>CONCLUSION</b>Among 21 new genomovars, 3 were major genomovars, with Chinese Y. pestis DFR as the major genomovars which had obvious distribution characteristics.</p>

Sources of infection on human plague in Qinghai province / 中华流行病学杂志

<p><b>OBJECTIVE</b>To study the biological and genetic characteristics of 119 strains of Yersinia (Y.) pestis isolated from plague patients in Qinghai province, from 1958-2012.</p><p><b>METHODS</b>Both regular methods and different region(DFR)molecular typing techniques were used to study the epidemiological characteristics on 119 strains of Y. pesticin Qinghai during 1958-2012. Sources of Y. pestis from two outbreaks, in Nangqian county in 2004 and in Xinghai county in 2009,Qinghai province were also analyzed.</p><p><b>RESULTS</b>105 strains of Y. pestis were identified as Qinghai-Tibet Plateau Ecotype while the other 6 strains as Qilian Mountains Ecotype. 84.03% (100/119) of the tested strains carried 4 virulence factors F1(+), Pst I(+), VW(+) and Pgm(+)). 97.30% (72/74) of the tested strains showed high virulence. Strains that carrying 52×10(6), 65×10(6), 92×10(6) plasmids were distributed in Hainan, Haibei, Haixi,Yushu,Guoluo, Huangnan and Huangyuan counties. Genomovar 5 and 8 were the main gene types that circling around Qinghai Lake. Genomovar 10 was found in strains of Y. pesticin Nangqian county while Genomovar 8 was found in the strains isolated from human plague patient during the epidemics in Xinghai county in Qinghai.</p><p><b>CONCLUSION</b>Data from biological and genetic analyses on the epidemics of human plague in Nangqian county in 2004 and in Xinghai county in 2009 demonstrated that methods as DFR genotyping and virulence factors profiles, as well as plasmids profiles were powerful tools in confirming the human plague epidemics and sources of infection.</p>

Analysis on the results of etiology and serology of plague in Qinghai province from 2001 to 2010 / 中华预防医学杂志

<p><b>OBJECTIVE</b>To analyze the results of etiology and serology of plague among human and infected animals in Qinghai province from 2001 to 2010.</p><p><b>METHODS</b>Thirty-seven cases of human infected with plague, 53 541 different animal samples, 5 685 sets of vector insects flea and 49 039 different animal serum samples were obtained between 2001 and 2010. A total of 7 811 samples of serum from healthy farmers and herdsmen in 14 counties in Qinghai from 2005 to 2007 were collected. Yersinia pestis (Y. pestis) were detected in visceral and secretions from human, infected animals and vector insects, respectively. Plague antigen was detected by reverse indirect hemagglutination assay (RIHA) in those samples. Indirect hemagglutination assay (IHA) was used to test plague FI antibody in serum of human and infected animals.</p><p><b>RESULTS</b>37 human plague cases were confirmed, 21 strains of plague Y. pestis were isolated from human cases and 14 positive were detected out. 133 of 7 811 samples of human serum were IHA positive, with the positive rate at 1.7%. A total of 146 strains of plague were isolated from infected animals and vector insects, 99 out of which were from infected animals, with a ratio of Marmota himalayan at 72.7% (72/99) and the other 47 were from vector insects, with a ratio of callopsylla solaris at 68.1% (32/47). The number of IHA and PIHA positive were 300 and 10, respectively. A total of 3 animals and 3 insects species were identified as new epidemic hosts for plague. The natural plague focus of Microtus fuscus was discovered and confirmed and coexisted with natural focus of Marmota himalayan in Chengduo county, Yushu prefecture. The epidemic situation of plague is distributed mainly in Haixi, Yushu and Hainan prefectures.</p><p><b>CONCLUSION</b>From 2001 to 2010, animal infected with plague was detected in successive years and human plague was very common in Qinghai. New infected animals and vector insects species and new epidemic areas were confirmed, hence the trend of plague prevalence for humans and animals is very active in Qinghai province.</p>

Purification of native F1 antigen from Yersinia pestis EV76 anti its efficacy against Yersinia pestis in mice / 中华微生物学和免疫学杂志

Objective To purify native F1 antigen from E pestis EV76 strain and determine its ef-ficacy against Y. pestis. Methods A new purification method was developed by the substitution of physical disruption ( glass beads) for organic solvent ( acetone and toluene) one, followed by a combination of ammo-nium sulfate fractionation and SephacrylS-200HR column filtration chromatography. Groups of mice were im-munized with F1 antigen adsorbed to 25% aluminum hydroxide in PBS by intramuscular route. The immu-nized animals were challenged subeutaneously(s, c. ) with 104 CFU of Y. pestis strain 141 at 18 weeks after the primary immunization. Results There was no IgG titre difference between two groups of mice with one-dose immunization, whereas in the two-dose immunization groups, the group F1-40 μg induced a statistically higher antibody titre than the group F1-20 μg. Complete protection was observed for animals immunized with purified F1 antigen by s.c. route. In contrast, the control mice immunized with aluminum hydroxide suc-cumbed to a same dose of Y. pestis 141 challenge. Conclusion This purification strategy is a simple and ef-fective, and can be operated in a large scale. Native F1 antigen extracted from Y. pestis EV76 is highly im-munagenic, and can be used as a key antigen component to develop sub-unit vaccine of plague.