Objective: To investigate an outbreak of acute gastroenteritis at a vocational and technical school in Shaanxi Province in 2024, ao as to provide the reference for the handling of school outbreaks. Methods: The conducted case searches, individual case investigations, and on-site hygienic investigations were established in accordance with the Guidelines on outbreak investigation, prevention and control of Norovirus infection (2015). The potential risk factors were analyzed by case-control study. Anal swab samples from cases and all canteen staff, as well as environmental swab samples were collected to detect common intestinal pathogens. All reserved food samples in canteen were collected to test for common pathogenic bacteria. Results: From October 26 to November 5, 2024, a cumulative total of 53 cases were reported, with an attack rate of 1.47%. The main clinical symptoms included vomiting (83.02%), abdominal pain (56.60%), diarrhea (30.19%), and fever (26.42%). The epidemic curve suggested an intermittent common-source outbreak, with no obvious clustering characteristics in terms of the population and spatial distribution of cases. The case-control analysis revealed that having dinner at the rice-with-dishes-on-top stall on the first floor of the canteen on October 28 was a risk factor for illness (OR=11.025, 95%CI: 2.186-55.601). GⅡ norovirus was detected as positive in anal swab samples from 6 cases and 2 asymptomatic infected canteen staff, as well as in 3 environmental swab samples from the rice-with-dishes-on-top stall. The test results for common pathogenic bacteria in the reserved food samples were all negative. Conclusions This outbreak was caused by an acute gastroenteritis epidemic induced by GⅡ norovirus infection, with a transmission pattern consistent with an intermittent homologous outbreak. The possible source of infection was asymptomatic infected canteen staff mainly through foodborne trasmission, and having meals at the rice-with-dishes-on-top stall was the primary risk factor for this outbreak.

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 learn about the epidemic characteristics and temporal-spatial trends of human anthrax in Shaanxi Province, and to provide a theoretical basis for prevention and control of anthrax.Methods:The epidemic data of human anthrax in Shaanxi Province from 1955 to 2024 were collected for descriptive epidemiological analysis. Joinpoint regression model was used to analyze the trend of anthrax incidence rate. The trend at all times and different intervals were estimated by average annual percent change (AAPC) and annual percent change (APC), respectively. Based on the number of human anthrax cases in each county (district) of Shaanxi Province from 1980 to 2024, datasets were constructed in segments every five years for global and local spatial autocorrelation analysis.Results:From 1955 to 2024, a total of 3 900 cases of human anthrax were reported in Shaanxi Province, with 124 deaths. The average annual incidence rate was 0.18/100 000 and the fatality rate was 3.18%. The incidence rate of human anthrax generally showed a downward trend (AAPC = - 3.21, t = - 1.99, P = 0.044), with the fastest decline rate from 1977 to 1993 (APC = - 15.24, t = - 4.08, P < 0.001). A temporal and regional distribution analysis was conducted on 484 human anthrax cases in Shaanxi Province from 1980 to 2024. The peak period of incidence was from July to September, accounting for 52.27% (253/484). The cities with a relatively high number of reported cases were Weinan City (201 cases), Xianyang City (161 cases), and Xi'an City (77 cases), accounting for a total of 90.70% (439/484). A population distribution analysis was conducted on 93 human anthrax cases in Shaanxi Province from 2005 to 2024, with 73 males (78.49%) and 20 females (21.51%), resulting in a male to female ratio of 3.65 ∶ 1.00. The age range was 13 to 79 years old, with a median of 44 years old. The age group of 35 to 59 years old had a higher case of the disease, accounting for 65.59% (61/93). Farmers were the main occupation, accounting for 87.10% (81/93). The shortest time interval between onset and diagnosis of 93 human anthrax cases was 0 days, the longest was 47 days, and the median was 5 days. The results of global spatial autocorrelation analysis showed that there was spatial positive correlation in human anthrax cases from 1980 to 1984, 1985 to 1989, 2000 to 2004, and 2020 to 2024 (global Moran's I > 0, Z > 1.96, P < 0.05). The results of local spatial autocorrelation analysis showed that the high-high aggregation area of human anthrax cases was concentrated in the Guanzhong region. Conclusions:From 1955 to 2024, the incidence rate of human anthrax in Shaanxi Province generally shows a downward trend. The peak period of incidence is from July to September, and the affected populations are mainly middle-aged male farmers. Human anthrax cases from 1980 to 1984, 1985 to 1989, 2000 to 2004 and 2020 to 2024 show spatial clustering, with high-high clustering areas concentrated in the Guanzhong region.

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 spatial distribution and characteristics of iodine content in residential drinking water in Shaanxi Province, and provide a basis for scientific prevention and control of iodine deficiency disorders.Methods:From March to October 2022, an investigation was conducted in all counties (districts, referred to as counties) of Shaanxi Province, with administrative villages as survey units. For centralized water supply systems, two terminal water samples were collected, and iodine content was measured separately, with the average value representing the drinking water iodine content at that location. For decentralized water supply systems, a 10% sampling method was used to divide each administrative village into five areas (east, south, west, north, and center), with 10% of water wells sampled from each area (if fewer than 10 water wells, the well with the largest drinking population was selected; if fewer than 5 wells, all wells were sampled). One water sample was collected from each water well, and iodine content was determined using the arsenic-cerium catalytic spectrophotometry method. Spatial autocorrelation and spatial scan analysis were used to analyze the spatial distribution and characteristics of drinking water iodine content.Results:A total of 53 990 drinking water samples were collected, with a median water iodine content of 6.66 μg/L, ranging from 0.10 to 779.40 μg/L. Drinking water iodine content was detected in 112 counties, showing a significant spatial positive correlation (global autocorrelation, Moran's I = 0.74, Z = 43.83, P < 0.001). Local autocorrelation analysis showed that the difference in the distribution of iodine content in drinking water among 36 counties was statistically significant ( P < 0.05), with 22 counties showing low-low clustering and 12 counties showing high-high clustering. Spatial scanning identified three water iodine clustering areas, including two high-water iodine cluster areas and one low-water iodine cluster area. Conclusions:The distribution of iodine content in residential drinking water in Shaanxi Province shows significant spatial clustering and heterogeneity, requiring targeted interventions to achieve precise prevention and control of iodine deficiency disorders.

Objective To investigate iodine content in drinking water and clarify the distribution characteristics of iodine in water in Shaanxi Province.Methods A cross-sectional survey method was used to collect water samples from administrative villages in the province.Two tap water samples were taken from the centralized water supply villages,and 10％samples were taken from the decentralized water supply villages.Water iodine was detected by arsenic cerium catalytic spectrophotometry.Water iodine areas were divided according to national standards:＜40 μg/L was iodine deficiency area,40-100 μg/L was iodine adequate area,＞100 μg/L was high iodine area.According to the ecological regionification scheme of the Chinese Academy of Sciences,Shaanxi Province was divided into three types:the central and eastern Inner Mongolia Platea-Loess Plateau ecological region,the Fenwei Basin ecological region,and the Qinba Mountains ecological region.SPSS 25.0 was used for statistical analysis.Results The median of water iodine in Shaanxi Province was 6.66 μg/L.The survey of water iodine content was conducted in 22 848 administrative villages,1 309 townships,112 counties and 14 municipalities in the whole province.The median water iodine was less than 40 μg/L in 91.75％(20 963/22 848)of the administrative villages,between 40 and 100 μg/L in 7.40％(1 691/22 848)of the administrative villages,and more than 100 μg/L in 0.85％(194/22 848)of the administrative villages.The median of water iodine in the central and eastern Inner Mongolia Platea-Lose Plateau ecological zone,the Fenwei Basin ecological zone,and Qinba Mountains ecological zone was 12.35,8.88,and 2.00 μg/L,respectively,and the differences among different ecological zones were statistically significant(H=6 616.23,P＜0.001).The median of water iodine of centralized and decentralized water supply was 6.72 and 6.21 μg/L,respectively,and differences between different water supply methods were statistically significant(Z=5.638,P＜0.01).Conclusion The overall external environment of Shaanxi Province is iodine deficient,and most of the administrative villages are iodine deficient areas.There are a certain proportion of high iodine water source areas and suitable iodine areas.

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 learn about the epidemic characteristics and temporal-spatial trends of human anthrax in Shaanxi Province, and to provide a theoretical basis for prevention and control of anthrax.Methods:The epidemic data of human anthrax in Shaanxi Province from 1955 to 2024 were collected for descriptive epidemiological analysis. Joinpoint regression model was used to analyze the trend of anthrax incidence rate. The trend at all times and different intervals were estimated by average annual percent change (AAPC) and annual percent change (APC), respectively. Based on the number of human anthrax cases in each county (district) of Shaanxi Province from 1980 to 2024, datasets were constructed in segments every five years for global and local spatial autocorrelation analysis.Results:From 1955 to 2024, a total of 3 900 cases of human anthrax were reported in Shaanxi Province, with 124 deaths. The average annual incidence rate was 0.18/100 000 and the fatality rate was 3.18%. The incidence rate of human anthrax generally showed a downward trend (AAPC = - 3.21, t = - 1.99, P = 0.044), with the fastest decline rate from 1977 to 1993 (APC = - 15.24, t = - 4.08, P < 0.001). A temporal and regional distribution analysis was conducted on 484 human anthrax cases in Shaanxi Province from 1980 to 2024. The peak period of incidence was from July to September, accounting for 52.27% (253/484). The cities with a relatively high number of reported cases were Weinan City (201 cases), Xianyang City (161 cases), and Xi'an City (77 cases), accounting for a total of 90.70% (439/484). A population distribution analysis was conducted on 93 human anthrax cases in Shaanxi Province from 2005 to 2024, with 73 males (78.49%) and 20 females (21.51%), resulting in a male to female ratio of 3.65 ∶ 1.00. The age range was 13 to 79 years old, with a median of 44 years old. The age group of 35 to 59 years old had a higher case of the disease, accounting for 65.59% (61/93). Farmers were the main occupation, accounting for 87.10% (81/93). The shortest time interval between onset and diagnosis of 93 human anthrax cases was 0 days, the longest was 47 days, and the median was 5 days. The results of global spatial autocorrelation analysis showed that there was spatial positive correlation in human anthrax cases from 1980 to 1984, 1985 to 1989, 2000 to 2004, and 2020 to 2024 (global Moran's I > 0, Z > 1.96, P < 0.05). The results of local spatial autocorrelation analysis showed that the high-high aggregation area of human anthrax cases was concentrated in the Guanzhong region. Conclusions:From 1955 to 2024, the incidence rate of human anthrax in Shaanxi Province generally shows a downward trend. The peak period of incidence is from July to September, and the affected populations are mainly middle-aged male farmers. Human anthrax cases from 1980 to 1984, 1985 to 1989, 2000 to 2004 and 2020 to 2024 show spatial clustering, with high-high clustering areas concentrated in the Guanzhong region.

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 spatial distribution and characteristics of iodine content in residential drinking water in Shaanxi Province, and provide a basis for scientific prevention and control of iodine deficiency disorders.Methods:From March to October 2022, an investigation was conducted in all counties (districts, referred to as counties) of Shaanxi Province, with administrative villages as survey units. For centralized water supply systems, two terminal water samples were collected, and iodine content was measured separately, with the average value representing the drinking water iodine content at that location. For decentralized water supply systems, a 10% sampling method was used to divide each administrative village into five areas (east, south, west, north, and center), with 10% of water wells sampled from each area (if fewer than 10 water wells, the well with the largest drinking population was selected; if fewer than 5 wells, all wells were sampled). One water sample was collected from each water well, and iodine content was determined using the arsenic-cerium catalytic spectrophotometry method. Spatial autocorrelation and spatial scan analysis were used to analyze the spatial distribution and characteristics of drinking water iodine content.Results:A total of 53 990 drinking water samples were collected, with a median water iodine content of 6.66 μg/L, ranging from 0.10 to 779.40 μg/L. Drinking water iodine content was detected in 112 counties, showing a significant spatial positive correlation (global autocorrelation, Moran's I = 0.74, Z = 43.83, P < 0.001). Local autocorrelation analysis showed that the difference in the distribution of iodine content in drinking water among 36 counties was statistically significant ( P < 0.05), with 22 counties showing low-low clustering and 12 counties showing high-high clustering. Spatial scanning identified three water iodine clustering areas, including two high-water iodine cluster areas and one low-water iodine cluster area. Conclusions:The distribution of iodine content in residential drinking water in Shaanxi Province shows significant spatial clustering and heterogeneity, requiring targeted interventions to achieve precise prevention and control of iodine deficiency disorders.