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Objective:To learn about the epidemic dynamics and spatial epidemic characteristics of human brucellosis in Gansu Province.Methods:Data on human brucellosis in Gansu Province reported by China Disease Control and Prevention Information System from January 2016 to December 2020 were collected and analyzed by descriptive epidemiology and spatial clustering analysis.Results:A total of 10 025 cases of human brucellosis were reported in Gansu Province from 2016 to 2020, with a statistically significant difference in incidence rate between years (χ 2 = 242.86, P = 0.001). The incidence was the lowest in 2018 (6.03/100 000), and the highest in 2020 (11.39/100 000). The reported cases were concentrated in 45 - 55 years old, accounting for 34.52% (3 461/10 025); the male to female ratio was 2.91 ∶ 1.00 (7 458/2 567); farmers were the main occupation, accounting for 82.11% (8 232/10 025). Among the 86 counties (cities, districts) in Gansu Province, Yongchang County had the highest number of reported cases in 2020 (339 cases), and Sunan Yugur Autonomous County had the highest incidence in 2020 (190.89/100 000). Spatial autocorrelation analysis showed that there was significant spatial positive correlation between the incidence rate of human brucellosis in Gansu Province from 2016 to 2020 (global Moran's I > 0, Z > 1.96, P < 0.05), showing a spatial clustering distribution. The high-high clustering areas were concentrated in Yongchang County and Sunan Yugur Autonomous County. Conclusion:In Gansu Province, the main population of human brucellosis is middle-aged male farmers, and the incidence of brucellosis is spatially clustered.
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Objective:To analyze the changes of spatial, seasonal, and age distribution of brucellosis among humans and animals in Gansu Province and to provide a reference for the next step in formulating prevention and control measures.Methods:Reported data of brucellosis of humans and animals in Gansu Province from 2018 to 2020 were collected. The human epidemic data were obtained from "China Disease Control and Prevention Information System", and the positive data of animals were obtained from the monthly report provided by Gansu Animal Disease Control Center. Human brucellosis was classified and analyzed according to year, month, age and region, and livestock brucellosis was classified according to year, month, population and region. ArcGIS 10.2 software was used to analyze the spatial epidemiological characteristics of the data. Measuring Geographic tool was used to calculate the shifting distance of the center of the disease incidence in humans and animals from 2018 to 2020.Results:From 2018 to 2020, a total of 6 375 cases of human brucellosis were reported in Gansu Province. The 40 - 59 age group accounted for 54.96% (3 504/6 375), 1 584 cases were reported in 2018, 1 787 cases were reported in 2019, and 3 004 cases were reported in 2020. The high incidence time of human brucellosis was July and November. A total of 48 180 brucellosis-positive animals (heads) were detected, of which 47 342 were positive sheep, accounting for 98.26% (47 342/48 180). The high incidence time of brucellosis among animals was October. Among the 14 cities (prefectures), the top cities of livestock brucellosis reported were Qingyang City, Zhangye City and Jiuquan City. The center of disease incidence among humans was located in Gulang County, Wuwei City. The center of disease incidence among animals was located in Wuwei City in 2018 and Qingyang City in 2020.Conclusions:The cases of brucellosis in humans and animals in Gansu Province are on the increase. In some areas, there are problems of separation of human and animal epidemics. It is necessary to actively strengthen monitoring and implement measures to prevent and control brucellosis in humans and animals in high-risk areas to curb the spread of the epidemic.
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Objective:To understand the plague epidemic characteristics in the natural foci of the Qilian Mountains-A-erh-chin Mountains Himalayan marmot plague in Gansu Province, and to provide scientific basis for innovative prevention and control of the plague in combination with local conditions. Methods:A retrospective study was used to collect the monitoring data of the natural foci of plague in Gansu Province from 2011 to 2018 (from the epidemic surveillance files of the Center for Disease Control and Prevention of Gansu Province and direct network reporting information). Descriptive epidemiological method was used to analyze the plague epidemic characteristics of natural foci of the Qilian Mountains-A-erh-chin Mountains Himalayan marmot plague in Gansu Province from 2011 to 2018, including the distribution of host animals, pathogenic and serological testing of the plague bacteria, and the epidemic characteristics of human plague. Results:From 2011 to 2018, the total average marmot density in the natural foci of the Qilian Mountains-A-erh-chin Mountains Himalayan marmot plague in Gansu Province was 0.21/hm 2, of which Tianzhu County had the highest average marmot density of 0.58/hm 2, and Jiayuguan City had the lowest average marmot density of 0.01/hm 2. A total of 381 strains of Yersinia pestis were isolated in the foci, of which 4 were isolated from human corpses, 298 were host animals, and 79 were infectious vectors. Among them, the top 3 counties (cities) of isolated strains were Aksai County (38.85%, 148 strains), Subei County (31.50%, 120 strains) and Yumen City (16.27%, 62 strains). A total of 6 860 marmot serum, 1 769 dog serum were tested, the F1 antibody positive rates were 2.70% (185/6 860), 8.42% (149/1 769); and the F1 antigen positive rate of 814 animal materials was 4.30% (35/814), respectively. There were 4 times of human plague, 4 cases occurred and 4 cases died; 3 times occurred in Subei County and 1 time in Yumen City. The onset months were July, September, November and December. Active contact with infected animals such as shepherd dogs was the main route of infection, and migrant herders were the key occupation population. Conclusions:The animal epidemic situation in the natural foci of the Qilian Mountains-A-erh-chin Mountains Himalayan marmot plague in Gansu Province is active, and the plague presents different epidemic states in different regions. The prevention and control measures should be taken according to local conditions and guided by classification to strictly prevent the occurrence and transmission of the plague.
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Objective:To analyze the dynamics of plague epidemic in Spermophilus alaschanicus plague foci of Gansu Province from 1962 to 2018, and to provide evidence for plague control and prevention. Methods:The data of Spermophilus alaschanicus plague in Gansu Province from 1962 to 2018 were collected and organized from epidemic surveillance and epidemic summary. The method of descriptive epidemiology was used to analyze plague, including population (regional distribution, time distribution) and animal (geographic distribution, infected animals and vectors) epidemiology. Results:There was only one case of human plague in the Spermophilus alaschanicus plague foci of Gansu Province from 1962 to 2018. The total incidence of the disease was 26 cases, 11 cases died, the incidence rate was 29.89% (26/87), and the mortality was 42.31% (11/26). The cases were mainly distributed in Liuzhai Township and Xinyuan Township of Huining County. The outbreak occurred from July to August. Plague bacteria were isolated from the plague foci of Gansu Province during two peak epidemics of the plague among animals from 1962 to 2018. The bacteria detection area was located in 2 rural areas that were the northern area of Liuzhai in Huining County, and the neighboring Zhongtian and Fuxing in Pingchuan District. Five places were determined to be the animal epidemic sites. The endemic species were Spermophilus alaschanicus and Vulpescorsac, and the vector species were Citellophilus tesquorus mongolicus and Neopsylla abagaitui. The epidemic time of animal plague was from April to August. Totally 115 positive serum F1 antibodies were obtained. Among them, 92 positive serum samples were detected in Huining County and 23 in Pingchuan District. The positive blood coagulation sites were distributed in 11 villages, 5 towns of 2 counties (districts). The surveillance results showed that 30 species of animals belonging to 5 orders, 11 families, 5 subfamilies, and 21 genera were found in the foci, most of them were Spermophilus alaschanicus, which accounting for 69.1% (2 464/3 567) of the total species of rodents in the past years. A total of 12 482.9 hm 2 were investigated by sampling method, and 9 709 Spermophilus alaschanicus were captured, with an average density of 0.78/hm 2. Conclusions:The plague is intermittently prevalent in Gansu's Spermophilus alaschanicus plague foci. So the prevention and control strategies should be adjusted in time according to the changes. In residential areas, we should take the initiative to strengthen the monitoring of rat situation and the publicity and education of human plague prevention knowledge.
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Objective:To analyse the effects of meteorological factors on plague epidemic in Himalayana marmot plague natural foci in Subei and Sunan counties of Gansu Province. Methods:The surveillance data of plague from 1973 to 2016 in Himalayan marmot foci of Subei and Sunan counties (from Gansu Provincial Center for Disease Control and Prevention) and the meteorological factors (rainfall, temperature, relative humidity) of current, preceding first, second and third years (the first, second and third years before the reference year, from China Meteorological Data Sharing Service System) were collected. In order to build generalized additive model (GAM), the positive rate of plague was used as dependent variable while meteorological factors of the current, preceding first, second and third years were used as independent variables. The influence of meteorological factors on plague was quantitatively analyzed by using R2.3.2 software. Results:In 2006 - 2016, compared with 1974 - 1983, the average temperature in Subei rose by 0.99 ℃, the average relative humidity rose by 3.55%RH, and the average rainfall rose by 12.16 mm; in Sunan County, the average temperature rose by 1.00 ℃, the average relative humidity rose by 2.01%RH, and the average rainfall rose by 14.60 mm. From 1973 to 2016, 11 cases of human plague with 7 cases of dead (12 cases of attack) occurred in the investigated district. The average rainfall of the preceding third year of Subei rose every 1.00 mm within a certain range, the animal plague occurred rose by 0.40%. The average relative humidity of preceding second year of Subei rose every 1.00%RH within a certain range, animal plague occurred rose by 11.66%. The average rainfall of the preceding first year of Sunan rose every 1.00 mm within a certain range, the animal plague occurred rose by 1.32%. The average relative humidity of preceding third year of Sunan rose every 1.00%RH within a certain range, animal plague occurred rose by 11.96%. The average temperature of the preceding second year of Subei, Sunan rose every 1.00 ℃ within a certain range, animal plague rose 73.17%, 70.18%, respectively.Conclusions:The occurrence and prevalence of plague in Himalayana marmot are closely related to meteorological factors, and the temperature within a certain range (but not continuously) not only promotes the epidemic of plague, but also has a lag effect. In addition, the effects of different types of climate in the same foci on the prevalence of animal plague vary.
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Objective To analyze the relationship between meteorological variables and the prevalence of marmot plague in the Himalayan marmot foci of Subei County,Gansu Province.Methods The surveillance data (from Gansu Provincial Center for Disease Control and Prevention) on human plague,the meteorological factors (average rainfall,temperature,relative humidity) data (from China Meteorological Data Sharing Service Network) of the current and preceding (relative to current year as a reference) first,second and third years and meteorological factors data of the current and preceding first,second and third months in Subei of Himalayan marmot foci from 1973 to 2014 were collected.The association of positive rate of plague bacteriological detection and meteorological factors was evaluated by using SAS 9.3 software.The influence of meteorological factors on the epidemic of marmot plague was analyzed by the logistic regression analysis.Results From 1973 to 2014,6 human plague cases with 5 dead cases occurred in Subei County.The positive rate of plague bacteriological detection was positively correlated with the average relative humidity of current year and the average temperature of preceding first year (r =0.366,0.385,P ＜ 0.05),and it was negatively correlated with the average relative humidity of preceding third year (r =-0.304,P ＜ 0.05);the positive rate of plague bacteriological detection was positively correlated with the average rainfall of preceding first month (r =0.212,P ＜ 0.05),and it was negatively correlated with the average relative humidity of preceding second and third months (r =-0.196,-0.201,P ＜ 0.05).The risk factor of animal plague epidemic in marmot foci in Subei County was average temperature of current month [odds ratio (OR) =1.304,95％ confidence intervals (CI):1.195-1.422],and the protective factor was average relative humidity of preceding third month (OR =0.960,95％CI:0.932-0.988).Conclusions The prevalence of marmot plague is closely associated with meteorological factors in the natural plague foci of Subei County of Gansu Province.The temperature not only plays a role in promoting the prevalence of plague,but also has a lagging effect.Therefore,the meteorological factors can be considered as a reference of the plague prevalence in Himalayan marmot plague foci.
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Objective To investigate the correlation of meteorological factors with the numbers of marmots and parasitic fleas in the plague foci of Himalayan marmot in Subei County and Sunan County of Gansu Province.Methods The surveillance data (from Gansu Provincial Center for Disease Control and Prevention) of natural plague foci of Subei,Sunan of Himalayan marmot from 1982 to 2016 and the meteorological factors data (from China Meteorological Data Sharing Service Network) such as annual average temperature,rainfall and relative humidity during the same period were collected.The correlation between marmot density,body flea index and meteorological factors were analyzed by SAS 9.3 software.Based on the meteorological data as an independent variable in current year and previous 1,2,and 3 years (relative to previous 1,2,and 3 years as the reference),the marmot density as the dependent variable,the time series semiparametric generalized additive model (GAM) was established to quantitatively study the nonlinear effect of meteorological factors on the marmot density by R2.3.2 software.Results From 1982 to 2016,the marmot density in Subei County of Gansu Province was 0.29-6.63 per hectare,and the body flea index range was 0.04-4.56;the marmot density in Sunan County of Gansu Province was 1.22-7.92 per hectare,and the body flea index range was 0.06-0.42.In Subei County,the marmot density was correlated with the previous 1 year rainfall and relative humidity,respectively (r =0.43,0.36,P＜ 0.05),and negatively correlated with the average temperature of the year and the previous 1,3 years (r =-0.58,-0.55,-0.41,P ＜ 0.05).In Sunan County,the marmot density was correlated with the relative humidity of the year and the previous 1 year rainfall and relative humidity,respectively (r =0.36,0.57,0.43,P ＜ 0.05).In Subei County,the body flea index was negatively correlated with the average temperature of the year and the previous 1,2,3 years,respectively (r =-0.57,-0.43,-0.31,-0.37,P ＜ 0.05).In Sunan County,there was a negative correlation between the body flea index and the average temperature of the year and the previous 1,2,3 years (r =-0.71,-0.46,-0.38,-0.40,P ＜ 0.05).After controlling other influencing factors,the results of the GAM showed that for every 1 mm increase in rainfall of the year in Subei County,the marmot density increased 0.93％;for every 1％ increase in relative humidity of the previous 3 year in Subei County,the marmot density increased 25.34％;for every 1 mm increase in rainfall of the previous 3 year in Sunan County,the marmot density increased 1.69％.Conclusions The numbers of marmots in the plague foci of Himalayan marmot in Subei County and Sunan County of Gansu Province are closely related to rainfall and relative humidity,and the influence has different hysteresis effects.Surface temperature is a important factor affecting the population of parasitic fleas.
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Objective@#To investigate the correlation of meteorological factors with the numbers of marmots and parasitic fleas in the plague foci of Himalayan marmot in Subei County and Sunan County of Gansu Province.@*Methods@#The surveillance data(from Gansu Provincial Center for Disease Control and Prevention) of natural plague foci of Subei, Sunan of Himalayan marmot from 1982 to 2016 and the meteorological factors data (from China Meteorological Data Sharing Service Network) such as annual average temperature, rainfall and relative humidity during the same period were collected. The correlation between marmot density, body flea index and meteorological factors were analyzed by SAS 9.3 software. Based on the meteorological data as an independent variable in current year and previous 1, 2, and 3 years (relative to previous 1, 2, and 3 years as the reference), the marmot density as the dependent variable, the time series semiparametric generalized additive model (GAM) was established to quantitatively study the nonlinear effect of meteorological factors on the marmot density by R2.3.2 software.@*Results@#From 1982 to 2016, the marmot density in Subei County of Gansu Province was 0.29-6.63 per hectare, and the body flea index range was 0.04-4.56; the marmot density in Sunan County of Gansu Province was 1.22-7.92 per hectare, and the body flea index range was 0.06-0.42. In Subei County, the marmot density was correlated with the previous 1 year rainfall and relative humidity, respectively (r= 0.43, 0.36, P < 0.05), and negatively correlated with the average temperature of the year and the previous 1, 3 years (r=-0.58,-0.55,-0.41, P < 0.05). In Sunan County, the marmot density was correlated with the relative humidity of the year and the previous 1 year rainfall and relative humidity, respectively (r= 0.36, 0.57, 0.43, P < 0.05). In Subei County, the body flea index was negatively correlated with the average temperature of the year and the previous 1, 2, 3 years, respectively(r=-0.57,-0.43,-0.31,-0.37, P < 0.05). In Sunan County, there was a negative correlation between the body flea index and the average temperature of the year and the previous 1, 2, 3 years (r=-0.71,-0.46,-0.38,-0.40, P < 0.05). After controlling other influencing factors, the results of the GAM showed that for every 1 mm increase in rainfall of the year in Subei County, the marmot density increased 0.93%; for every 1% increase in relative humidity of the previous 3 year in Subei County, the marmot density increased 25.34%; for every 1 mm increase in rainfall of the previous 3 year in Sunan County, the marmot density increased 1.69%.@*Conclusions@#The numbers of marmots in the plague foci of Himalayan marmot in Subei County and Sunan County of Gansu Province are closely related to rainfall and relative humidity, and the influence has different hysteresis effects. Surface temperature is a important factor affecting the population of parasitic fleas.
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Objective To investigate the relationship between fleas density of Spermophilus alaschanicue and host density as well as meteorological factors.Methods The densities of fleas of Spermophilus alaschanicue and meteorological temperature,precipitation,relative humidity data in the same period from 1977 to 2014 in plague natural foci of Spermophilus alaschanicue of Gansu Province were collected.In order to further establish the multiple linear regression and the stepwise regression analysis model,SAS 9.3 software was used to explore the linear correlation analysis between fleas index number,density of Spermophilus alaschanicue and meteorological factors.Results The average body flea index positively correlated with the density of Spermophilus alaschanicue (r =0.34,P ＜ 0.05),in addition,hole fleas index was in negative correlation with the average temperature of the current and preceding first,second and third years (r =-0.44,-0.39,-0.45,-0.54,P ＜ 0.01).However,hole fleas index positively correlated with the average rainfall of preceding first year (r =0.38,P ＜ 0.05).More specifically,the monthly body flea index was negatively correlated with the average rainfall and the average temperature of current,preceding first,second,and third months,and the average relative humidity of current month (r =-0.23,-0.34,-0.43,-0.29,-0.25,-0.33,-0.36,-0.38,-0.26,P ＜ 0.01).After multiple linear regression analysis,the following equations were obtained:body fleas index =3.983 1 + 0.695 1 × Sperrnophilus density-0.004 9 × average annual rainfall;hole fleas index =10.780 4 + 0.009 1 × average annual rainfall-0.216 2 × annual average relative humidity.Conclusions The relationship between fleas density of Spermophilus alaschanicue and the environment is complex,they have mutual connection as well as mutual restriction.Except Spermophilus density affects the number of fleas,the two most important meteorological factors which affect the flea body index are temperature and rainfall.In addition,the relationship between meteorological factors and flea body index shows somewhat lagging behind for two to three months.
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Objective To explore the effects of meteorological factors on population densities of the host and the prevalence of animal plague in the natural plague foci of Spermophilus alaschanicus.Methods The surveillance data of seroprevalence rate in natural plague foci of Spermophilus alaschanicus of Gansu Province in current year,one previous year (relative to current year as a reference),as well as two and three previous years’ meteorological data such as average annual rainfall,temperature,relative humidity were collected from 1962 to 2014.SAS 9.3 software was used for correlation and regression analysis of the influencing meteorological factors on the density of Spermophilus alaschanicus and prevalence of animal plague;generalized additive model (GAM) was used for quantitative study of meteorological factors on density of Spermophilus alaschanicus;logistic regression analysis was used to study the effect of meteorological factors on prevalence of Spermophilus alaschanicus plague.Results Serum positive rate of Spermophilus alaschanicus was positively correlated with average annual rainfall of current and previous one year,and with relative humidity of current year (r =0.279,0.341,0.654,P ＜ 0.05);serum positive rate was negatively correlated with average annual temperature of current and preceding first,second and third years (r =-0.360,-0.339,-0.273,-0.323,P ＜ 0.05).The average annual rainfall of preceding second and third years was significantly associated with the densities of Spermophilus alaschanicus by GAM parameter estimation (t =2.88,2.42,P ＜ 0.05).The average annual rainfall of preceding second and third years was significantly associated with the densities of Spermophilus alaschanicus by GAM nonparameter estimation (x2=31.580,13.428,P ＜ 0.05),but the effect was nonlinear.Multivariate logistic regression analysis showed that average annual rainfall of preceding first year [odds ratio (OR) =2.475,95％ confidence interval (C/):1.175-5.213] was risk factor for the prevalence of the animal plague in the natural plague foci of Spermophilus alaschanicus.Conclusions Rainfall is risk factor for the prevalence of the animal plague in the natural plague foci of Spermophilus alaschanicus.There is a lag effect of rainfall on the numbers of hosts and the prevalence of Spermophilus alaschanicue plague.When the rainfall in the region (not continuously) reaches a certain amount,it will provide favorable conditions for the spread of Yersinia pestis.
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Objective To summarize and analyze the epidemic situation and trend of animal plague in plague foci of Gansu section of Golmud-Dunhuang railway,and provide basic reference for prevention and control of the plague.Methods The quantity of Marmot,rate of carrying fleas and flea index,plague serological and etiology detection results,the cross analyzing results of the railway section and the animal plague foci in Gansu section of Dolmud-Dunhuang railway (Akesai and Subei counties) from 2010 to 2015 were analyzed via the retrospective analysis method.Results The total average density of Marmot of Golmud-Dunhuang railway crossing area Akesai and Subei counties was between 0.23-0.41 per hectare between 2010 and 2015.The rate of parasitic dye fleas in plague foci of Akesai was between 11.30％ and 32.65％,body flea index was 0.74-1.84.The rate of parasitic fleas dye fleas in plague foci of Subei was between 5.34％ and 14.07％,the flea index was 0.25-2.04.The etiology detection Marmot plague of Akesai and Subei was 2 049,142 of them were positive,the positive rate was 6.93％;592 groups of vector were detected,44 of them were positive;the positive rate was 7.43％.There was no statistically significant difference between inspection bacteria rate and parasitic vector inspection rate of Marmot (x2 =0.014,P ＞ 0.05).Totally 1 719 serums of Marmot were tested,132 of them were positive,the positive rate was 7.68％.Totally 421 serums of Canis lupus familiaris were detected,61 of them were positive,the positive rate was 14.49％.There was statistically significant difference between the serum positive rate of Marmot and Canis lupus familiaris (x2 =19.116,P ＜ 0.05).Totally 17 animal foci were found along the railway in 2013,the nearest distance of the foci of bid from construction was 0.5 km,popular area was 61.02 km2,and 1 360 people were directly threatened.Conclusions Animal plague in Akesai and Subei regions along Golmud-Dunhuang railway is highly active.So we must take effective measures to guarantee the smooth progress of railway construction.
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We studied Yersinia infection and carriage in shepherd dog on the natural foci of Marmota himalayana plague and investigated the substitution or antagonism relationship among three pathogenic Yersinia in nature,providing a novel approach for prevention and control of plague.Blood sample and rectal swab specimens from shepherd dogs were collected.Rectal swab specimens were detected and isolated for Y.enterocolitican and Y.pseudotuberculosis.IHA was used to measure the positive rate of F1 antibody.Results showed that among 88,94,70 and 64 serum specimens respectively from Akesai,Subei,Sunan,and Tianzhu,IHA positive rates were 31.82％,32.98％,2.86％ and 1.56％ separately.A total of 236 anal swab specimens of shepherd dog were collected,among which one Y.kristensenii strain and 2 non-pathogenic Y.enterocolitica strain were recovered from Akesai and Subei respectively,where plague was violently prevalent in animals.All the results indicate that shepherd dogs in natural foci of M.himalayana plague where plague in animals are prevalent with non-pathogenic Y.enterocolitica,is an evidence of antagonism relationship in three pathogenic Yersinia.