Objective To investigate the global burden of visceral leishmaniasis (VL) from 1990 to 2021 and predict the trends in the burden of VL from 2022 to 2035, so as to provide insights into global VL prevention and control. Methods The global age-standardized incidence, prevalence, mortality and disability-adjusted life years (DALYs) rates of VL and their 95% uncertainty intervals (UI) were captured from the Global Burden of Disease Study 2021 (GBD 2021) data resources. The trends in the global burden of VL were evaluated with average annual percent change (AAPC) and 95% confidence interval (CI) from 1990 to 2021, and gender-, age-, country-, geographical area- and socio-demographic index (SDI)-stratified burdens of VL were analyzed. The trends in the global burden of VL were projected with a Bayesian age-period-cohort (BAPC) model from 2022 to 2035, and the associations of age-standardized incidence, prevalence, mortality, and DALYs rates of VL with SDI levels were examined with a smoothing spline model. Results The global age-standardized incidence [AAPC = -0.25%, 95% CI: (-0.25%, -0.24%)], prevalence [AAPC = -0.06%, 95% CI: (-0.06%, -0.06%)], mortality [AAPC = -0.25%, 95% CI: (-0.25%, -0.24%)] and DALYs rates of VL [AAPC = -2.38%, 95% CI: (-2.44%, -2.33%)] all appeared a tendency towards a decline from 1990 to 2021, and the highest age-standardized incidence [2.55/10⁵, 95% UI: (1.49/10⁵, 4.07/10⁵)], prevalence [0.64/10⁵, 95% UI: (0.37/10⁵, 1.02/10⁵)], mortality [0.51/10⁵, 95% UI: (0, 1.80/10⁵)] and DALYs rates of VL [33.81/10⁵, 95% UI: (0.06/10⁵, 124.09/10⁵)] were seen in tropical Latin America in 2021. The global age-standardized incidence and prevalence of VL were both higher among men [0.57/10⁵, 95% UI: (0.45/10⁵, 0.72/10⁵); 0.14/10⁵, 95% UI: (0.11/10⁵, 0.18/10⁵)] than among women [0.27/10⁵, 95% UI: (0.21/10⁵, 0.33/10⁵); 0.06/10⁵, 95% UI: (0.05/10⁵, 0.08/10⁵)], and the highest mortality of VL was found among children under 5 years of age [0.24/10⁵, 95% UI: (0.08/10⁵, 0.66/10⁵)]. The age-standardized incidence (r = -0.483, P < 0.001), prevalence (r = -0.483, P < 0.001), mortality (r = -0.511, P < 0.001) and DALYs rates of VL (r = -0.514, P < 0.001) correlated negatively with SDI levels from 1990 to 2021. In addition, the global burden of VL was projected with the BAPC model to appear a tendency towards a decline from 2022 to 2035, and the age-standardized incidence, prevalence, mortality and DALYs rates were projected to be reduced to 0.11/10⁵, 0.03/10⁵, 0.02/10⁵ and 1.44/10⁵ in 2035, respectively. Conclusions Although the global burden of VL appeared an overall tendency towards a decline from 1990 to 2021, the burden of VL showed a tendency towards a rise in Central Asia and western sub-Saharan African areas. The age-standardized incidence and prevalence rates of VL were relatively higher among men, and the age-standardized mortality of VL was relatively higher among children under 5 years of age. The global burden of VL was projected to continue to decline from 2022 to 2035.

Objective To investigate the suitable habitats of Phlebotomus chinensis in Gansu Province, so as provide insights into effective management of mountain-type zoonotic visceral leishmaniasis (MT-ZVL). Methods The geographical coordinates of locations where MT-ZVL cases were reported were retrieved in Gansu Province from 2015 to 2023, and data pertaining to 26 environmental variables were captured, including 19 climatic variables (annual mean temperature, mean diurnal range, isothermality, temperature seasonality, maximum temperature of the warmest month, minimum temperature of the coldest month, temperature annual range, mean temperature of the wettest quarter, mean temperature of the driest quarter, mean temperature of the warmest quarter, mean temperature of the coldest quarter, annual precipitation, precipitation of the wettest month, precipitation of the driest month, precipitation seasonality, precipitation of the wettest quarter, precipitation of the driest quarter, precipitation of the warmest quarter, and precipitation of the coldest quarter), five geographical variables (elevation, annual normalized difference vegetation index, vegetation type, landform type and land use type), and two population and economic variables (population distribution and gross domestic product). Twelve species distribution models were built using the biomod2 package in R project, including surface range envelope (SRE) model, generalized linear model (GLM), generalized additive model (GAM), multivariate adaptive regression splines (MARS) model, generalized boosted model (GBM), classification tree analysis (CTA) model, flexible discriminant analysis (FDA) model, maximum entropy (MaxEnt) model, optimized maximum entropy (MAXNET) model, artificial neural network (ANN) model, random forest (RF) model, and extreme gradient boosting (XGBOOST) model. The performance of 12 models was evaluated using the area under the receiver operating characteristic curve (AUC), true skill statistics (TSS), and Kappa coefficient, and single models with high performance was selected to build the optimal ensemble models. Factors affecting the survival of Ph. chinensis were identified based on climatic, geographical, population and economic variables. In addition, the suitable distribution areas of Ph. chinensis were predicted in Gansu Province under shared socioeconomic pathway 126 (SSP126), SSP370 and SSP585 scenarios based on climatic data during the period from 1991 to 2020, from 2041 to 2060 (2050s), and from 2081 to 2100 (2090s) . Results A total of 11 species distribution models were successfully built for prediction of potential distribution areas of Ph. chinensis in Gansu Province, and the RF model had the highest predictive accuracy (AUC = 0.998). The ensemble model built based on the RF model, XGBOOST model, GLM, and MARS model had an increased predictive accuracy (AUC = 0.999) relative to single models. Among the 26 environmental factors, precipitation of the wettest quarter (12.00%), maximum temperature of the warmest month (11.58%), and annual normalized difference vegetation index (11.29%) had the greatest contributions to suitable habitats distribution of Ph. sinensis. Under the climatic conditions from 1991 to 2020, the potential suitable habitat area for Ph. chinensis in Gansu Province was approximately 5.80 × 10⁴ km², of which the highly suitable area was 1.42 × 10⁴ km², and primarily concentrated in the southernmost region of Gansu Province. By the 2050s, the unsuitable and lowly suitable areas for Ph. chinensis in Gansu Province had decreased by varying degrees compared to that of 1991 to 2020 period, while the moderately and highly suitable areas exhibited expansion and migration. By the 2090s, under the SSP126 scenario, the suitable habitat area for Ph. chinensis increased significantly, and under the SSP585 scenario, the highly suitable areas transformed into extremely suitable areas, also showing substantial growth. Future global warming is conducive to the survival and reproduction of Ph. chinensis. From the 2050s to the 2090s, the highly suitable areas for Ph. chinensis in Gansu Province will be projected to expand northward. Under the SSP126 scenario, the suitable habitat area for Ph. chinensis in Gansu Province is expected to increase by 194.75% and 204.79% in the 2050s and 2090s, respectively, compared to that of the 1991 to 2020 period. Under the SSP370 scenario, the moderately and highly suitable areas will be projected to increase by 164.40% and 209.03% in the 2050s and 2090s, respectively, while under the SSP585 scenario, they are expected to increase by 195.98% and 211.66%, respectively. Conclusions The distribution of potential suitable habitats of Ph. sinensis gradually shifts with climatic changes. Intensified surveillance and management of Ph. sinensis is recommended in central and eastern parts of Gansu Province to support early warning of MT-ZVL.

Objective:To study the correlation between serum N-terminal pro-B-type natriuretic peptide (NT-proBNP) level and echocardiographic parameters in patients with chronic Keshan disease, providing reference for diagnosis and prognosis evaluation of chronic Keshan disease.Methods:Ninety-nine patients with chronic Keshan disease who received standardized treatment at Jingchuan County People's Hospital in Pingliang City, Gansu Province from January to December 2020 were selected. Among them, 16 patients were classified as cardiac function grade Ⅱ according to New York Heart Association (NYHA), 69 as grade Ⅲ and 14 as grade Ⅳ. The patients underwent echocardiography and their serum NT-proBNP level was measured using fluorescence immunochromatography. The differences in serum NT-proBNP levels among patients with different cardiac function grades were compared, and the correlation between cardiac function grades, serum NT-proBNP level and echocardiographic parameters was analyzed.Results:The serum NT-proBNP levels in patients with cardiac function grades Ⅱ, Ⅲ, and Ⅳ were (1 107.26 ± 268.03), (2 125.98 ± 293.02), and (8 268.59 ± 2 659.50) pg/ml, respectively. The differences among the three groups were statistically significant ( F = 13.94, P < 0.001). The serum NT-proBNP level was positively correlated with cardiac function grades ( r = 0.44, P < 0.001), left ventricular end-diastolic diameter, left ventricular end-systolic diameter, and left atrial diameter ( r = 0.45, 0.52, 0.38, P < 0.001), and negatively correlated with fractional shortening and left ventricular ejection fraction ( r = - 0.39, - 0.46, P < 0.001). Conclusions:The serum NT-proBNP level in patients with chronic Keshan disease with different cardiac function grades is different, and is positively correlated with echocardiographic parameters reflecting the degree of cardiac structural and functional impairment. The NT-proBNP level may become an early diagnostic, grading, and prognostic indicator for chronic Keshan disease.

Objective:To investigate the intelligence status of children aged 10 - 12 in rural areas of Linxia Hui Autonomous Prefecture (referred to as Linxia) in Gansu Province.Methods:From September to November 2019, a cross-sectional study was carried out to investigate the intelligence status of children aged 10 to 12 in 8 counties (cities) of Linxia. Chinese Raven's Progressive Matrices (rural version) was used for intelligence test and children's intelligence quotient (IQ) was calculated by regular mold to evaluate children's intelligence level.Results:A total of 1 721 children in Linxia were tested for intelligence, with an average IQ of 103.2. Among them, low intelligence (≤69) accounted for 1.0% (18/1 721), borderline (70 - 79) accounted for 3.0% (52/1 721), middle and lower (80 - 89) accounted for 8.4% (144/1 721), moderate (90 - 109) accounted for 56.6% (974/1 721), middle and upper (110 - 119) accounted for 21.9% (377/1 721), excellent (120 - 129) accounted for 7.8% (135/1 721), extremely excellent (≥130) accounted for 1.2% (21/1 721). There were 635, 598 and 488 children aged 10, 11 and 12, respectively, with an average IQ of 106.1, 103.3 and 99.2. There were 919 males and 802 females, with an average IQ of 102.9 and 103.4, respectively.Conclusion:In 2019, the intelligence of children aged 10 to 12 in rural areas of Linxia has reached the moderate level.

Objective To investigate the spatiotemporal clustering characteristics of the reported incidence of visceral leishmaniasis (VL) in Gansu Province from 1993 to 2023, so as to provide insights into the containment of VL and prevention of VL recurrence. Methods County (district)-level epidemical data of VL in Gansu Province from 1993 to 2023 were collected, and the geographical information database of reported VL incidence in Gansu Province was created according to the county-level administrative code and electronic maps in Gansu Province. In addition, the spatial autocorrelation analysis and hot spot analysis of the reported VL incidence were performed in Gansu Province using the software ArcGIS 10.8. Results A total of 2 597 VL cases were reported in Gansu Province from 1993 to 2023, with an annual average incidence rate of 3.036/10⁵. Spatial autocorrelation analysis showed spatial clustering of the reported VL incidence in Gansu Province (Moran’s I = 0.605, Z = 5.240, P < 0.001), appearing high-high clustering features (Getis-Ord G = 0.080, Z = 4.137, P < 0.001), and high-high clustering of the reported incidence of VL was identified in Diebu County, Tanchang County, Zhouqu County and Wenxian County. Hot spot analysis showed hot-spot areas of the reported VL incidence in Tanchang County, Zhouqu County, Wudu District and Wenxian County along the Bailong River basins and cold-spot areas in Qin’an County and Gangu County. Conclusions There was spatial clustering and hot spots of the reported VL incidence in Gansu Province from 1993 to 2023. Intensified surveillance and control is required to prevent the spread of VL.

Objective:To evaluate the application of the standard of "Delimitation and Classification of Keshan Disease Areas" (GB 17020-2010, Standard for short), learn about the applicability of its technical indicators and requirements, and provide a basis for revision of the Standard.Methods:In March 2022, provinces with severe epidemic areas of Keshan disease or new cases reported in recent years were selected, including Gansu Province, Inner Mongolia Autonomous Region, Shandong Province, Shaanxi Province, Yunnan Province, Shanxi Province, Liaoning Province, and Chongqing City. Multi-stage stratified sampling method and questionnaire survey were adopted to collect information on the application of Standard by relevant health institutions.Results:A total of 448 questionnaires were collected, including 445 valid. The survey results showed that 87.64% (390/445) of the respondents were aware of the Standard, and 64.72% (288/445) had received training on the Standard. Eighty-two point two per cent (365/445) of the respondents believed that the Standard was simple and easy to operate, 83.82% (373/445) believed that the determination of the diseased townships was scientific and reasonable, and could be effectively implemented, and 83.60% (372/445) believed that the determination of historical epidemic areas was applicable to the current situation of Keshan disease; 38.88% (173/445), 38.20% (170/445), and 37.98% (169/445) of the respondents believed that the classification indicators for classifying epidemic areas (severe, moderate, and mild epidemic areas) were not applicable to the current situation of the disease in the local or provinces with Keshan disease, respectively. Among the indicators for epidemic areas classification, 30.79% (137/445), 29.21% (130/445), and 28.54% (127/445) of the respondents thought that the annual prevalence, the annual number of new cases and the annual incidence were most suitable for classification of Keshan disease areas.Conclusions:The Standard has been applied well in practice. However, based on the current situation of Keshan disease, it is suggested to redefine the standard for the severity of the disease and the classification of historical epidemic areas.

Objective:To explore the distribution characteristics of common clinical manifestations of elbow joint in patients with endemic fluorosis and their correlation with the influencing factors.Methods:A cross-sectional survey was conducted on all permanent adult residents in 13 endemic fluorosis villages in Gaotai and Gaolan counties of Gansu province. The survey included: ① Demographic information, family history, and current medical history. ② Physical examination specifically focued on the orthopedic clinical presentations. ③Taking DR films of the forearm (including elbow joint) and calf (including knee joint), and classify the elbow joint to grade K-L based on X-ray manifestations. ④ Measuring height and weight, and calculating BMI index. ⑤Applying the Mayo elbow joint rating scale to evaluate elbow joint function. Based on the survey results, the distribution characteristics of clinical symptoms and signs of elbow joint in patients with skeletal fluorosis, as well as the distribution characteristics and correlation of factors affecting elbow joint function such as age, gender, disease course, BMI, K-L grade, etc were described. The comparison of counting data and rates were analyzed with χ2 test or Fisher exact probability test. Pearson′s test was used for correlation analysis of continuous data that conforms to normal distribution, and Spearman test was used for non-normal distribution measurement and counting data. The correlation analysis of ordered hierarchical data was conducted using Kendall′s Tau- b test. Results:①Among 501 patients with skeletal fluorosis, a total of 465 cases (92.8%) were diagnosed with elbow joint pain. A total of 185 cases (36.9%) were with elbow joint tenderness, 300 cases (59.9%) were with elbow joint enlargement, 415 cases (82.8%) were with morning stiffness of the elbow joint, 102 cases (20.4%) were with cubital tunnel syndrome, 153 cases (30.5%) were with positive forearm extensor tendon traction test, and 97 cases (19.4%) were with positive forearm flexor tendon traction test. The detection rate of elbow joint rotation limitation was the highest among those with ROM ranging from 30 ° to 70 ° (261/501, 52.1%), and the detection rate of elbow joint extension and flexion limitation was the highest among those with ROM ranging from 50 ° to 90 °(274/501, 54.7%). ②Among 501 patients with skeletal fluorosis, a total of 465 cases were found to have symptoms and positive signs in the elbow joint, with the detection rate in males being lower than that in females, with a significant difference ( χ2=41.19, P<0.001). The majority of patients were between the ages of 50 and 65 (274/501, 58.9%), with a body mass index of <18 (217, 46.67%), K-L arthritis with a radiologic grade of Ⅲ (256/501, 55.0%), and a disease course of >30 years (217/501, 46.67%). ③The correlation between clinical characteristics, the Mayo score, and various influencing factors of skeletal fluorosis found a high correlation between pain and age ( r=0.79, P<0.001) and pain and disease course ( r=0.71, P<0.001). The ROM of extension and flexion was negatively correlated with age ( r=-0.43, P<0.001), K-L grade ( r=-0.67, P<0.001), and disease course ( r=-0.48, P<0.001); Elbow tunnel syndrome was positively correlated with age ( r=0.72, P<0.001). The Mayo functional score was negatively correlated with age ( r=-0.35, P<0.001). Conclusion:Early morning stiffness of the elbow joint (<30 min), limited rotation of the elbow joint, limited extension and flexion of the elbow joint, and cubital tunnel syndrome (degree Ⅰ) have a high detection rate in the population with skeletal fluorosis. Age, course of disease, and degree of joint degeneration have a significant impact on elbow joint function in patients with fluorosis.

Objective:To analyze the epidemic status and spatial and temporal cluster distribution of visceral leishmaniasis (VL) in Gansu Province, and to provide evidence for making precise prevention and control measures and epidemic surveillance.Methods:The data of VL cases in Gansu Province reported in the China Disease Prevention and Control Information System Infectious Disease Reporting Information Management System from 2015 to 2021 were collected, descriptive epidemiology analysis was performed (three distribution of the disease). SaTScan v9.6 and ArcMap 10.7 were used for spatio-temporal cluster analysis.Results:A total of 368 VL cases were reported from 2015 to 2021, 89.13% (328/368) were concentrated in Longnan City and Gannan Tibetan Autonomous Prefecture. The number of VL cases increased year by year from 2015 to 2017, reaching a peak in 2017 (79 cases, accounting for 21.47%), and had decreased year by year since 2018. There were cases every month throughout the year, and the peak was in April in spring (38 cases). The ratio of male to female patients was 1.3 ∶ 1.0 (208/160). Scattered children aged less than 5 years old were more common (41.30%, 152/368). The spatio-temporal cluster analysis showed that both the spatial and temporal aggregation zones of VL in Tanchang County and Chengxian County were of statistical significance ( P < 0.05). Conclusion:The incidence of VL in Gansu Province is showing a low epidemic trend, having spatio-temporal aggregation, and precise monitoring and prevention and control should be strengthened in epidemic areas with different prevalence levels.

Objective:To analyze and predict the transmission risk of visceral leishmaniasis in Gansu Province based on an ecological niche model, providing a basis for the development of precise prevention and control measures and epidemic surveillance.Methods:The information of reported cases of visceral leishmaniasis in Gansu Province from 2015 to 2021 were collected from the National Infectious Disease Reporting Information Management System, and the longitude and latitude coordinates of the distribution points of cases and the data of 19 climate variables, 5 geographical variables and 2 socio-economic variables within the region were obtained. Based on an ecological niche model, a model for predicting the transmission risk of visceral leishmaniasis was constructed using the maximum entropy algorithm (MaxEnt), and its performance was evaluated by the area under the receiver operating characteristic curve (AUC). Then the importance of each environmental variable of the model was evaluated, and the distribution area of visceral leishmaniasis transmission risk in Gansu Province was predicted.Results:A total of 368 cases of visceral leishmaniasis were reported in Gansu Province from 2015 to 2021, of which 89.13% (328/368) were from Longnan City and Gannan Tibetan Autonomous Prefecture (Gannan Prefecture). The number of cases peaked in 2017 (79 cases, 21.47%). The model had high prediction accuracy (AUC = 0.985). The results of model analysis showed that the important climate variable affecting the distribution of visceral leishmaniasis was the average temperature in the coldest quarter (contribution value of 3.1), the geographical variables were land use type (contribution value of 52.6) and vegetation cover type (contribution value of 8.5), and the socio-economic variable was population size (contribution value of 14.3). The distribution results of transmission risk showed that high, medium and low risk areas exhibited a gradual transition from the southern part to the northwest part of Gansu Province. The high risk areas were mainly located in the central and southern parts of Longnan City and the southern part of Gannan Prefecture, accounting for 0.18% of the total area of the province. Medium and low risk areas accounted for 0.48% and 2.47% of the total area of the province, respectively; and areas with no risk accounted for 96.87%.Conclusions:The ecological niche model predicts that the spread of visceral leishmaniasis in Gansu Province is characterized by point like dispersion and local high aggregation distribution. It is necessary to strengthen monitoring and prevention and control of high-risk areas such as Longnan City and Gannan Prefecture.

Objective:To investigate the epidemiological situation of drinking water-type endemic fluorosis in Gansu Province, and scientifically evaluate the effectiveness of water improvement and fluoride reduction projects in preventing and controlling the disease.Methods:The drinking water-type endemic fluorosis areas in Gansu Province were divided into five regions according to different ecological types: the Longzhong Loess Plateau Hilly Area in central Gansu, the Longdong Loess Plateau Gully Area in eastern Gansu, the Longnan Qinling Zhongshan Canyon Area in southern Gansu, the Gobi area of the Hexi Desert, and the Alpine Grassland Meadow Area in southern Gansu. In 2021, a survey was conducted on the basic situation, running situation of the water improvement and fluoride reduction projects, fluoride content in drinking water(fluorine ion-selective electrode), and the prevalence of dental fluorosis (Dean) among children aged 8 to 12 in all drinking water-type endemic fluorosis villages in the five regions. The pertinent assessments were executed in accordance with national guidelines such as the "Standards for Drinking Water Quality" (GB 5749-2006) and "Diagnosis of Dental Fluorosis" (WS/T 208-2011).Results:A total of 2 000 villages in drinking water-type endemic fluorosis areas were monitored, among which 1 999 villages had implemented water improvement and fluoride reduction projects, with a coverage rate of 99.95% (1 999/2 000). All water improvement and fluoride reduction projects were operating normally, with no intermittent operation or scrapping. A total of 34 616 children aged 8 to 12 were investigated for dental fluorosis. The detection rate of dental fluorosis was 4.18% (1 448/34 616), and the dental fluorosis index was 0.09. There was a statistically significant difference in the detection rate of dental fluorosis among children of different ages (χ 2 = 69.77, P < 0.001). The difference in the detection rate of dental fluorosis among children of different ecological types of areas was statistically significant (χ 2 = 775.11, P < 0.001). The dental fluorosis index of children aged 8 - 12 was significantly correlated with the historical water fluoride level ( r = 0.29, P = 0.042). The water improvement time in the Gobi area of the Hexi Desert was significantly correlated with the detection rate of dental fluorosis in local children ( r = - 0.48, P = 0.023). Conclusions:In 2021, the prevention and control of drinking water-type endemic fluorosis in all villages in Gansu Province has reached the national control standards. However, due to the different ecological characteristics and changes in water source distribution in different ecological types of areas, it is still necessary to further strengthen the monitoring of the condition of drinking water-type endemic fluorosis in all the affected villages and consolidate the existing prevention and control achievements.