This study analyzed soil-transmitted nematode infection surveillance data for children 3-9 years of age in Shaanxi Province from 2016 to 2023,to provide a scientific basis for control strategies for soil-transmitted nematode infections in children in the province.Since 2016,according to the requirements of the National Schistosomiasis and Soil-transmitted Nematode Surveillance Program(Trial),several counties and districts in Shaanxi Province were selected as surveillance sites every year.According to geo-graphical position,the surveillance sites were divided into five areas:east,west,south,north and middle,and one administrative vil-lage(community)was selected in each area for monitoring.The eggs of soil-transmitted nematodes(hookworm,Ascaris lumbricoides,Trichuris trichiura,and Enterobius vermicularis)were detected with the Kato-Katz technique in children 3-9 years of age at each sur-veillance site,and the eggs of Enterobius vermicularis were detected again with the cellophane tape anal swab method.The infection rate and intensity for E.vermicularis were calculated.Detection was performed in 12 462 children 3-9 years old at 75 surveillance sites in Shaanxi Province from 2016 to 2023;84 cases of soil-borne nematode infections were detected,and the overall infection rate was 0.67%.The infection rates for Ascaris lumbricoides and E.vermicularis were 0.18%(22/12 462)and 0.50%(62/12 462),respec-tively,and the infection rates for Trichuris trichiura and hookworm were not found.The infection rates of soil-transmitted nematodes in children were 1.28%(16/1 250),0.16%(2/1 252),1.25%(17/1 365),1.20%(18/1 494),0.17%(2/1 169),1.45%(20/1 382),0.00,and 0.36%(9/251),respectively.A linear trend was observed among years(χ2=11.973,P<0.001).The infection rates in the Weifen Basin ecological region,Loess Plateau ecological region,and Qinba Mountains ecological region were 0.51%,1.19%,and 0.72%,respectively,and the differences were statistically significant(χ2=9.726,P=0.008).Significant differences in infection rates were observed among scattered children(1.63%),preschool children(0.66%),and students(0.57%)(χ2=11.189,P=0.004).No significant differences in infection rates were observed by gender,age,and education level.Compared with the infection rates in the entire country and other provinces,the infection rate of soil-transmitted nematodes among children in Shaanxi Province was low,and the main infection species were Ascaris lumbricoides and E.vermicularis.The infection rates greatly varied within Shaanxi Prov-ince,possibly because of differences in economic development levels,children′s living habits,and personal hygiene status across re-gions.In the future,comprehensive control measures should be taken to strengthen the monitoring and control of key areas,popula-tions,and parasite species.

Objective:To analyze the epidemic characteristics and trends of visceral leishmaniasis (VL) in Shaanxi Province, and provide a basis for formulating control strategies.Methods:The information on VL cases in Shaanxi Province from January 2012 to December 2024 were obtained from the Shaanxi Provincial Infectious Disease Reporting Management System, and demographic data were collected from the Shaanxi Statistical Yearbook. Descriptive epidemiological method was used to analyze the prevalence and the distribution by the three dimensions (time, region, and population). Joinpoint 4.9.1.0 software and Geoda 1.6 software were used for regression analysis and spatial clustering analysis, respectively. SuperMap 8C software was used for visualization.Results:From January 2012 to December 2024, a total of 304 cases of VL were reported in Shaanxi Province, with an annual incidence rate of 0.06/100 000. VL cases occurred in all months of the year in Shaanxi Province with no significant seasonality, yet the onset was predominantly concentrated from April to August(52.30%, 159/304). The majority of cases were male (61.51%, 187/304), aged 5 months to 4 years (17.11%, 52/304), and farmers (67.11%, 204/304). A total of 54 districts (counties, cities) of 10 cities in the province had reported cases, mainly concentrated in Weinan City (49.34%, 150/304). Joinpoint regression analysis revealed a significant overall upward trend in the VL incidence rate in Shaanxi Province from 2012 to 2024 [average annual percent change (AAPC) = 12.60%, 95% confidence interval ( CI): 6.01% - 19.62%, t = 3.95, P < 0.001]. The year 2020 was identified as a turning point in the trend. The incidence rate showed a rapid upward trend from 2012 to 2020 [annual percent change (APC) = 23.75%, 95% CI: 13.33% - 35.12%, t = 5.62, P < 0.001]. Global spatial autocorrelation analysis indicated significant positive spatial autocorrelation in VL incidence in 2012, 2014, 2015, 2018, and 2022 (Moran's I > 0, Z > 1.96, P < 0.05). Local spatial autocorrelation analysis identified 12 "high-high" clustering areas from 2012 to 2024, mainly located in Shangluo City in southern Shaanxi Province, and Weinan City and Yan'an City in northern Shaanxi Province. Conclusions:From 2012 to 2024, VL cases in Shaanxi Province are predominantly male farmers. The incidence of VL shows an overall upward trend, with significant spatial clustering. The prevention and control situation is severe. It is imperative to strengthen control measures, including vector disinfection and health education, to effectively control the spread and transmission of VL.

This study analyzed soil-transmitted nematode infection surveillance data for children 3-9 years of age in Shaanxi Province from 2016 to 2023,to provide a scientific basis for control strategies for soil-transmitted nematode infections in children in the province.Since 2016,according to the requirements of the National Schistosomiasis and Soil-transmitted Nematode Surveillance Program(Trial),several counties and districts in Shaanxi Province were selected as surveillance sites every year.According to geo-graphical position,the surveillance sites were divided into five areas:east,west,south,north and middle,and one administrative vil-lage(community)was selected in each area for monitoring.The eggs of soil-transmitted nematodes(hookworm,Ascaris lumbricoides,Trichuris trichiura,and Enterobius vermicularis)were detected with the Kato-Katz technique in children 3-9 years of age at each sur-veillance site,and the eggs of Enterobius vermicularis were detected again with the cellophane tape anal swab method.The infection rate and intensity for E.vermicularis were calculated.Detection was performed in 12 462 children 3-9 years old at 75 surveillance sites in Shaanxi Province from 2016 to 2023;84 cases of soil-borne nematode infections were detected,and the overall infection rate was 0.67%.The infection rates for Ascaris lumbricoides and E.vermicularis were 0.18%(22/12 462)and 0.50%(62/12 462),respec-tively,and the infection rates for Trichuris trichiura and hookworm were not found.The infection rates of soil-transmitted nematodes in children were 1.28%(16/1 250),0.16%(2/1 252),1.25%(17/1 365),1.20%(18/1 494),0.17%(2/1 169),1.45%(20/1 382),0.00,and 0.36%(9/251),respectively.A linear trend was observed among years(χ2=11.973,P<0.001).The infection rates in the Weifen Basin ecological region,Loess Plateau ecological region,and Qinba Mountains ecological region were 0.51%,1.19%,and 0.72%,respectively,and the differences were statistically significant(χ2=9.726,P=0.008).Significant differences in infection rates were observed among scattered children(1.63%),preschool children(0.66%),and students(0.57%)(χ2=11.189,P=0.004).No significant differences in infection rates were observed by gender,age,and education level.Compared with the infection rates in the entire country and other provinces,the infection rate of soil-transmitted nematodes among children in Shaanxi Province was low,and the main infection species were Ascaris lumbricoides and E.vermicularis.The infection rates greatly varied within Shaanxi Prov-ince,possibly because of differences in economic development levels,children′s living habits,and personal hygiene status across re-gions.In the future,comprehensive control measures should be taken to strengthen the monitoring and control of key areas,popula-tions,and parasite species.

Objective:To analyze the epidemic characteristics and trends of visceral leishmaniasis (VL) in Shaanxi Province, and provide a basis for formulating control strategies.Methods:The information on VL cases in Shaanxi Province from January 2012 to December 2024 were obtained from the Shaanxi Provincial Infectious Disease Reporting Management System, and demographic data were collected from the Shaanxi Statistical Yearbook. Descriptive epidemiological method was used to analyze the prevalence and the distribution by the three dimensions (time, region, and population). Joinpoint 4.9.1.0 software and Geoda 1.6 software were used for regression analysis and spatial clustering analysis, respectively. SuperMap 8C software was used for visualization.Results:From January 2012 to December 2024, a total of 304 cases of VL were reported in Shaanxi Province, with an annual incidence rate of 0.06/100 000. VL cases occurred in all months of the year in Shaanxi Province with no significant seasonality, yet the onset was predominantly concentrated from April to August(52.30%, 159/304). The majority of cases were male (61.51%, 187/304), aged 5 months to 4 years (17.11%, 52/304), and farmers (67.11%, 204/304). A total of 54 districts (counties, cities) of 10 cities in the province had reported cases, mainly concentrated in Weinan City (49.34%, 150/304). Joinpoint regression analysis revealed a significant overall upward trend in the VL incidence rate in Shaanxi Province from 2012 to 2024 [average annual percent change (AAPC) = 12.60%, 95% confidence interval ( CI): 6.01% - 19.62%, t = 3.95, P < 0.001]. The year 2020 was identified as a turning point in the trend. The incidence rate showed a rapid upward trend from 2012 to 2020 [annual percent change (APC) = 23.75%, 95% CI: 13.33% - 35.12%, t = 5.62, P < 0.001]. Global spatial autocorrelation analysis indicated significant positive spatial autocorrelation in VL incidence in 2012, 2014, 2015, 2018, and 2022 (Moran's I > 0, Z > 1.96, P < 0.05). Local spatial autocorrelation analysis identified 12 "high-high" clustering areas from 2012 to 2024, mainly located in Shangluo City in southern Shaanxi Province, and Weinan City and Yan'an City in northern Shaanxi Province. Conclusions:From 2012 to 2024, VL cases in Shaanxi Province are predominantly male farmers. The incidence of VL shows an overall upward trend, with significant spatial clustering. The prevention and control situation is severe. It is imperative to strengthen control measures, including vector disinfection and health education, to effectively control the spread and transmission of VL.

Objective:To study the epidemic characteristics of kala-azar in Shaanxi Province, and to provide scientific basis for formulating effective prevention and control measures.Methods:Information of kala-azar confirmed cases and clinically diagnosed cases whose current addresses were reported in Shaanxi Province in the Surveillance Report Management System of China Disease Control and Prevention Information System from 2011 to 2022 was collected. Trend analysis was made on the number of cases in each year, and descriptive epidemiological methods were used to analyze the onset time, regional and population distribution characteristics and the time interval from onset to diagnosis of kala-azar cases.Results:A total of 225 kala-azar cases were reported in Shaanxi Province from 2011 to 2022, and the number of cases showed an increasing trend (χ 2trend = 98.50, P < 0.001), with the highest number in 2020 (42 cases). The onset time was mainly from March to May (77 cases, 34.22%). The top three cities with the number of reported cases were Hancheng (65 cases, 28.89%), Shangluo (47 cases, 20.89%) and Weinan cities (44 cases, 19.56%). The male to female ratio was 1.74∶1.00 (143/82), the age of onset was mainly concentrated in the age group of 36 - 60 years old (111 cases, 49.33%), and the occupation was mainly farmers (150 cases, 66.67%). The median interval from onset to diagnosis was 11 days, and 78.22% (176/225) of the cases were diagnosed within 1 month. Conclusions:From 2011 to 2022, the overall incidence of kala-azar in Shaanxi Province has showed an upward trend, with the main population being middle-aged male farmers. The main affected areas are Hancheng, Shangluo and Weinan cities. It is urgent to strengthen the surveillance and prevention and control of kala-azar in key populations and key regions.

Objective: To investigate risk factors and epidemiological characteristics of bacillary dysentery outbreaks in three schools, and to provide scientific basis for the prevention and control of the epidemic in the future. Methods: Case definition was established. All suspected, possible and confirmed cases of all students and faculty members from 3 schools (A, B, C) were selected for epidemiological investigation. Control group was used for case-control analysis, and relevant samples were collected for laboratory testing. Results: A total of 132 cases were found in 3 schools, all of which were from students, with the incidence rate of 17.74%. The morbidity in kindergarten A was 20.00%, in center primary school B it was 21.74%, and in junior middle school C it was 11.61%. Cohort studies and casecontrol studies suggested that schools are exposed places and that washing hands with raw water in schools was possible risk factor [OR(95%CI) =4.50(1.01-20.11)]. Nine stool samples were tested in laboratory, among which 8 were positive for Shigella(88.99%), and Shigella was detected in the end nodes of school s pipeline network, the water samples from canteen bucket, and the floor drains of sewer pipe. Conclusion The bacillary dysentery outbreaks in 3 schools was caused by Shigella, which may be due to fecal contamination of domestic water in 3 schools before the start of the school year. It is suggested to strengthen the management of centralized water supply and construction in rural areas, intensify the supervision at all levels, and sanitation and disinfection before school opens at all levels.

【Objective】 To assess the epidemiological characteristics and transmission risk of asymptomatic COVID-19 infection in Shaanxi Province. 【Methods】 A dense population database of COVID-19 cases in Shaanxi Province was constructed as of March 26, 2020, and 28 asymptomatic infected patients were selected through case epidemiological investigation report for descriptive analysis. 【Results】 In Shaanxi Province, the majority of asymptomatic COVID-19 infections were in the 20-59 years old group, and women took up a higher proportion than men. 82.14% of asymptomatic infections were found in the centralized isolation state. Nearly 80% of asymptomatic infections and confirmed cases were mainly exposed by living together in the family. The median number of days from last contact with the source of infection for all asymptomatic infected persons was 13, with 3 (10.71%) showing clinical symptoms. Epidemiological investigations showed that asymptomatic infections could spread as a result of shared family life. 【Conclusion】 At present, imported cases in Shaanxi Province continue to exist. Considering the concealed transmission of asymptomatic infections, prevention and control work is still facing challenges.

Objective:By analyzed the transmission patterns of 4 out of the 51 COVID-19 cluster cases in Shaanxi province to provide evidences for the COVID-19 control and prevention.Methods:The epidemiological data of RT-PCR test-confirmed COVID-19 cases were collected. Transmission chain was drawn and the transmission process was analyzed.Results:Cluster case 1 contained 13 cases and was caused by a family of 5 who traveled by car to Wuhan and returned to Shaanxi. Cluster case 2 had 5cases and caused by initial patient who participated family get-together right after back from Wuhan while under incubation period. Cluster case 3 contained 10 cases and could be defined as nosocomial infection. Cluster case 4 contained 4 cases and occurred in work place.Conclusion:Higher contact frequency and smaller places were more likely to cause a small-scale COVID-19 cluster outbreak, with potential longer incubation period. COVID-19 control strategies should turn the attention to infection prevention and control in crowded places, management of enterprise resumption and prevention of nosocomial infection.

Objective:To understand the incidence trend and epidemiological characteristics of COVID-19 in Shaanxi province.Methods:The incidence data of COVID-19 reported in Shaanxi as of 22 February, 2020 were collected for an epidemiological descriptive analysis.Results:A total of 245 confirmed cases of COVID-19 were reported in Shaanxi. Most cases were mild (87.76%). As time passed, the areas where confirmed cases were reported continued to increase. The case number in Xi’an was highest, accounting for nearly half of the total reported cases in the province. The epidemic pattern in Shaanxi had gradually shifted from imported case pattern to local case pattern, and the transmission of local cases was mainly based on family cluster transmission. The confirmed cases from different sources had caused the secondary transmission in Shaanxi. After February 7, the number of reported cases began to fluctuate and decrease stably, indicating a decrease-to-zero period.Conclusions:At present, the overall epidemic of COVID-19 in Shaanxi has gradually been mitigated. However, considering the approaching of return to work and study and the increasing of imported cases from other countries, the prevention and control of COVIS-19 in Shaanxi will face new challenges.

A total of 245 cases of COVID-19 in Shaanxi Province reported in the China information system for disease control and prevention as of February 24, 2020 were selected as the research objects, the cases are divided into imported cases (116 cases, 47.3%) and local cases (129 cases, 52.7%), their basic characteristics, time distribution, transmission mode, intergenerational interval and latent period transmission are analyzed. The age of local cases [(51.74±15.67) years old], female patients (69 cases, 53.5%), housework and retired staff (40 cases, 31.0%), and patients isolated at the time of onset (50 cases, 38.8%) were higher than imported cases, respectively[(40.66±15.41) years old, (45 cases, 38.8%), (21 cases, 18.1%), (17 cases, 14.6%)] ( P values were < 0.05); The infection rate was 0.8% (31/3 666) in close contacts with local cases, which was lower than imported cases 2.0% (69/3 435) ( P<0.001); The main source of infection in local cases was relatives (70 cases, 54.3%), and the main way of infection was living together and party (90 cases, 69.8%); the proportion of latent period transmission in our province was 15.5% (20 cases), and the interval between the second-generation case and the source of infection was about 4 days, and the interval between generations was about 6 days. In summary, the main way of infection of local cases in Shaanxi Province was living together and party, there were a certain proportion of latent period transmission cases at present, it's suggested that the investigation of close contacts should be started 4 days or earlier before the onset of the case.