Objective:To analyze the infection status of Coxsackievirus B group (CVB) in regions affected by sudden unexplained death in Yunnan (referred to as sudden death in Yunnan), and to provide a scientific basis for formulating effective prevention and control strategies.Methods:A cross-sectional survey method was employed. The population from 16 counties (cities, districts, referred to as counties) affected by sudden death in Yunnan Province from 2002 to 2022 and the population from one non-affected county in 2021 and 2022 (control population) were classified into cases of sudden death in Yunnan (7 cases), co-occurring cases (29 cases), high-risk population (1 303 cases), and control population (270 cases). Blood samples were collected from these populations. By using enzyme-linked immunosorbent assay (ELISA), CVB immunoglobulin M (CVB-IgM) antibodies in the acute-phase serum samples of the population in the affected areas were detected, and CVB immunoglobulin G (CVB-IgG) antibodies in the convalescent-phase serum samples were detected. Both types of detections were carried out on the control population, and the test results were analyzed.Results:A total of 1 609 serum samples were tested, including 1 339 samples from the population in the affected areas (923 acute-phase samples and 416 convalescent-phase samples) and 270 samples from the control population. Among the 16 affected counties, positive CVB-IgM antibody results were detected in 9 counties. The overall positive rate of the population in the affected areas was higher than that of the control population [7.80% (72/923) vs. 4.44% (12/270), χ 2 = 40.78, P < 0.001]. The positive rates of the high-risk population in Dayao County and Lufeng City were both higher than that of the control population [(22.22% (22/99), 10.92% (25/229) vs. 4.44% (12/270), χ 2 = 27.37, 7.56, P < 0.05]. Positive CVB-IgG antibody results were detected in 7 counties. The overall positive rate of the population in the affected areas was higher than that of the control population [(4.09% (17/416) vs. 0.74% (2/270), χ 2 = 6.81, P = 0.009]. The positive rates of CVB-IgM and CVB-IgG antibodies in the population of the affected areas in Dayao County [22.22% (22/99), 9.80% (5/51)] were both higher than those of the control population ( P < 0.05). Among the five affected villages in Dayao County, the positive rates of CVB-IgM and CVB-IgG antibodies in the population of Aji Ju Village were the highest [25.49% (13/51), 3/13]. Conclusions:The positive rates of both CVB-IgM and CVB-IgG antibodies in the population of the areas affected by sudden death in Yunnan were higher than those of the control population, indicating that CVB infection occurred during the sudden death events in the above-mentioned affected areas.

Objective:To study the etiological relationship between Yunnan sudden unexplained death (hereinafter referred to as YNSUD) and the desmosomal protein gene mutation of arrhythmogenic right ventricular cardiomyopathy (ARVC).Methods:From September 2019 to August 2020, a cross-sectional survey method was used to select 9 key counties (cities) of YNSUD in Yunnan Province as survey sites. Autopsy cardiac blood samples of YNSUD cases ( n = 11) were collected, and peripheral venous blood samples of co-occurring case ( n = 1), case relatives ( n = 128), and control population ( n = 60) were collected. Genomic DNA from blood was extracted. After PCR amplification, 97 exons of 5 ARVC desmosomal protein genes, including plakophilin-2 (PKP2), desmoglein-2 (DSG2), desmocollin-2 (DSC2), desmoplakin (DSP), and junction plakoglobin (JUP) were sequenced by Sanger method, and the gene mutation was analyzed. Results:Compared with the control population, YNSUD cases, co-occurring case and case relatives carried 52 gene mutation sites in 36 exons of the ARVC desmosomal protein gene, with a total mutation rate of 37.11% (36/97). Among them, there were 21 in DSP gene, 10 in DSG2 gene, 8 in PKP2 gene, 8 in DSC2 gene, and 5 in JUP gene. YNSUD cases, co-occurring case and case relatives carried two same gene mutation sites: DSG2 gene exon 15 c.3321 T>C synonymous mutation and JUP gene exon 3 c.213 T>C synonymous mutation.Conclusions:The mutation rate of ARVC desmosomal protein gene is relatively high in the population of YNSUD. The two same gene mutation sites (DSG2 gene c.3321 T>C and JUP gene c.213 T>C) carried by YNSUD cases, co-occurring case and case relatives may be associated with the pathogenesis of YNSUD.

Objective:This study investigated the awareness and consumption of Trogia venenata among populations in regions affected by Yunnan unexplained sudden death (YUSD). The findings aim to support etiological research on YUSD and contribute to the formulation of preventive measures against Trogia venenata poisoning. Methods:This study was a case-control study. From 2018 to 2021, surveys were conducted in 90 villages across 25 counties within YUSD-affected areas in Yunnan Province. Households with YUSD cases were designated as case households, whereas households without YUSD cases served as controls, ande were selected through convenience sampling at a 3:1 ratio. An enhanced questionnaire was designed to collect information on the consumption of Trogia venenata, and symptoms following consumption. Frequency data were presented as percentages, and group comparisons were conducted using χ 2 tests or Fisher’s exact tests. Results:A total of 711 questionnaires were collected (response rate: 100%), comprising 175 case households and 536 control households. Trogia venenata was present in 80.82% of the villages surveyed. Among the 711 households, 15.89% reported consuming Trogia venenata, primarily through stir-frying (53.10%), followed by boiling (29.20%), boiling and stir-frying (15.93%), and steaming (1.77%). Most households (94.69%) consumed fresh fruiting bodies, with 69.02% consuming them fewer than three times annually. The consumption rates were higher among the case households than among the control households. Of the 113 households with a history of Trogia venenata consumption, 35.40% reported symptoms such as nausea, vomiting, and limb soreness. The proportions of affected families in each group were compared according to their source, cooking method, fruiting body status and consumption frequency. The proportion of affected families with high consumption frequency (≥3 times/year) was higher than that with low consumption frequency (<3 times/year). Among 421 YUSD cases, 63 cases (14.96%) had a history of Trogia venenata consumption before death, with 43 cases showing symptoms within the longest known latency period (14 d) for poisoning by this mushroom. Conclusions:Trogia venenata is prevalent in 80.82% of YUSD-affected regions, with 16.67% of the population reporting its consumption, predominantly as fresh fruiting bodies prepared by stir-frying or boiling. Confirmed Trogia venenata consumption was identified in 14.96% of YUSD cases, suggesting that mushroom poisoning is a significant risk factor for YUSD. Ongoing health education and interventions are critical for mitigating the risk of Trogia venenata poisoning.

Objective To investigate the effects of Amanita caojizong on cardiomyocyte apoptosis and the expression of apoptosis-related factors Bcl-2 and Bax,thereby providing experimental evidence for the prevention and treatment of Amanita caojizong poisoning.Methods Mouse cardiomyocytes(HL-1 cells)cultured in vitro were divided into an experimental group(treated with Amanita caojizong extract)and a control group(treated with PBS).After treatment with Amanita caojizong extract,apoptosis of HL-1 cells was observed using TUNEL staining,and the protein expression levels of Bax,Bcl-2,Caspase-3,and Cleaved Caspase-3 in HL-1 cardiomyocytes were detected by Western blot.Results Compared with the control group,the TUNEL staining showed significantly increased apoptotic fluorescence intensity in the Amanita caojizong extract-treated group.The protein expressions of Bax,Caspase-3,and Cleaved Caspase-3 in HL-1 cells in the Amanita caojizong-treated group were upregulated,while the expression of Bcl-2 was downregulated.Conclusion Amanita caojizong can promote apoptosis of mouse cardiomyocytes,and its mechanism may be associated with the Bcl-2/Bax pathway.

Objective To investigate the effects of Amanita caojizong on cardiomyocyte apoptosis and the expression of apoptosis-related factors Bcl-2 and Bax,thereby providing experimental evidence for the prevention and treatment of Amanita caojizong poisoning.Methods Mouse cardiomyocytes(HL-1 cells)cultured in vitro were divided into an experimental group(treated with Amanita caojizong extract)and a control group(treated with PBS).After treatment with Amanita caojizong extract,apoptosis of HL-1 cells was observed using TUNEL staining,and the protein expression levels of Bax,Bcl-2,Caspase-3,and Cleaved Caspase-3 in HL-1 cardiomyocytes were detected by Western blot.Results Compared with the control group,the TUNEL staining showed significantly increased apoptotic fluorescence intensity in the Amanita caojizong extract-treated group.The protein expressions of Bax,Caspase-3,and Cleaved Caspase-3 in HL-1 cells in the Amanita caojizong-treated group were upregulated,while the expression of Bcl-2 was downregulated.Conclusion Amanita caojizong can promote apoptosis of mouse cardiomyocytes,and its mechanism may be associated with the Bcl-2/Bax pathway.

Objective:To analyze the infection status of Coxsackievirus B group (CVB) in regions affected by sudden unexplained death in Yunnan (referred to as sudden death in Yunnan), and to provide a scientific basis for formulating effective prevention and control strategies.Methods:A cross-sectional survey method was employed. The population from 16 counties (cities, districts, referred to as counties) affected by sudden death in Yunnan Province from 2002 to 2022 and the population from one non-affected county in 2021 and 2022 (control population) were classified into cases of sudden death in Yunnan (7 cases), co-occurring cases (29 cases), high-risk population (1 303 cases), and control population (270 cases). Blood samples were collected from these populations. By using enzyme-linked immunosorbent assay (ELISA), CVB immunoglobulin M (CVB-IgM) antibodies in the acute-phase serum samples of the population in the affected areas were detected, and CVB immunoglobulin G (CVB-IgG) antibodies in the convalescent-phase serum samples were detected. Both types of detections were carried out on the control population, and the test results were analyzed.Results:A total of 1 609 serum samples were tested, including 1 339 samples from the population in the affected areas (923 acute-phase samples and 416 convalescent-phase samples) and 270 samples from the control population. Among the 16 affected counties, positive CVB-IgM antibody results were detected in 9 counties. The overall positive rate of the population in the affected areas was higher than that of the control population [7.80% (72/923) vs. 4.44% (12/270), χ 2 = 40.78, P < 0.001]. The positive rates of the high-risk population in Dayao County and Lufeng City were both higher than that of the control population [(22.22% (22/99), 10.92% (25/229) vs. 4.44% (12/270), χ 2 = 27.37, 7.56, P < 0.05]. Positive CVB-IgG antibody results were detected in 7 counties. The overall positive rate of the population in the affected areas was higher than that of the control population [(4.09% (17/416) vs. 0.74% (2/270), χ 2 = 6.81, P = 0.009]. The positive rates of CVB-IgM and CVB-IgG antibodies in the population of the affected areas in Dayao County [22.22% (22/99), 9.80% (5/51)] were both higher than those of the control population ( P < 0.05). Among the five affected villages in Dayao County, the positive rates of CVB-IgM and CVB-IgG antibodies in the population of Aji Ju Village were the highest [25.49% (13/51), 3/13]. Conclusions:The positive rates of both CVB-IgM and CVB-IgG antibodies in the population of the areas affected by sudden death in Yunnan were higher than those of the control population, indicating that CVB infection occurred during the sudden death events in the above-mentioned affected areas.

Objective:To study the etiological relationship between Yunnan sudden unexplained death (hereinafter referred to as YNSUD) and the desmosomal protein gene mutation of arrhythmogenic right ventricular cardiomyopathy (ARVC).Methods:From September 2019 to August 2020, a cross-sectional survey method was used to select 9 key counties (cities) of YNSUD in Yunnan Province as survey sites. Autopsy cardiac blood samples of YNSUD cases ( n = 11) were collected, and peripheral venous blood samples of co-occurring case ( n = 1), case relatives ( n = 128), and control population ( n = 60) were collected. Genomic DNA from blood was extracted. After PCR amplification, 97 exons of 5 ARVC desmosomal protein genes, including plakophilin-2 (PKP2), desmoglein-2 (DSG2), desmocollin-2 (DSC2), desmoplakin (DSP), and junction plakoglobin (JUP) were sequenced by Sanger method, and the gene mutation was analyzed. Results:Compared with the control population, YNSUD cases, co-occurring case and case relatives carried 52 gene mutation sites in 36 exons of the ARVC desmosomal protein gene, with a total mutation rate of 37.11% (36/97). Among them, there were 21 in DSP gene, 10 in DSG2 gene, 8 in PKP2 gene, 8 in DSC2 gene, and 5 in JUP gene. YNSUD cases, co-occurring case and case relatives carried two same gene mutation sites: DSG2 gene exon 15 c.3321 T>C synonymous mutation and JUP gene exon 3 c.213 T>C synonymous mutation.Conclusions:The mutation rate of ARVC desmosomal protein gene is relatively high in the population of YNSUD. The two same gene mutation sites (DSG2 gene c.3321 T>C and JUP gene c.213 T>C) carried by YNSUD cases, co-occurring case and case relatives may be associated with the pathogenesis of YNSUD.

Objective:To understand the electrocardiogram and echocardiography examination results of population in key areas of unexplained sudden death in Yunnan Province (referred to as Yunnan sudden death).Methods:From 2014 to 2022, electrocardiogram examination was performed on population (including same incident cases, relatives of the cases, villagers of the affected villages, and control individuals) in key areas of Yunnan sudden death from May to October each year. Echocardiography examination was performed on relatives of the cases and villagers of the affected villages, and the types of electrocardiogram and echocardiography changes were sorted out and analyzed.Results:Electrocardiogram examination was conducted on 1 same incident case, 241 relatives of the cases, 464 villagers of the affected villages, and 99 control individuals, respectively. The types of electrocardiogram changes in the same incident case were Q-T interval prolongation and sinus tachycardia. A total of 17 types of electrocardiogram changes were detected in the relatives of the cases, mainly including sinus arrhythmia (12.45%, 30/241), sinus bradycardia (11.20%, 27/241), and left axis deviation (8.30%, 20/241). A total of 21 types of electrocardiogram changes were detected in the villagers of the affected villages, mainly including left axis deviation (9.48%, 44/464), sinus bradycardia (8.19%, 38/464), and T-wave abnormalities (7.76%, 36/464). A total of 10 types of electrocardiogram changes were detected in the control individuals, mainly including sinus arrhythmia (12.12%, 12/99), T-wave abnormalities (9.09%, 9/99), and sinus bradycardia (7.07%, 7/99). Echocardiography examination was conducted on 49 relatives of the cases and 365 villagers of the affected villages, respectively. A total of 12 types of echocardiography changes were detected in the relatives of the cases, mainly including tricuspid regurgitation (18.37%, 9/49), decreased right ventricular diastolic function (8.16%, 4/49), aortic regurgitation (6.12%, 3/49), and atrial septal defect (6.12%, 3/49). A total of 15 types of echocardiography changes were detected in the villagers of the affected villages, mainly including tricuspid regurgitation (8.77%, 32/365), aortic regurgitation (6.85%, 25/365), and decreased left ventricular diastolic function (6.58%, 24/365).Conclusion:There are many types of changes in electrocardiogram and echocardiography in the population of key areas of Yunnan sudden death.

The etiology of Yunnan unexplained sudden death (YUSD) is still unknown, and it has been a serious endemic public health problem in Yunnan Province for a long time. Currently, known studies have shown that this disease is caused by multiple etiological factors. Due to limited study methods in the past, there are still certain limitations in understanding this disease. This article systematically reviews the etiological theories of YUSD since its first report, elaborates on the correlation between this disease and enterovirus infection, and combines metagenomic next-generation sequencing technology to make a prospect, in order to provide reference for future etiological studies.

Objective:To evaluate the effect of comprehensive intervention measures on Yunnan unexplained sudden death (YUSD) in Dali Prefecture, Yunnan Province, and to provide scientific basis for improving the prevention and control measures.Methods:Since 2010, Yunnan Province had implemented comprehensive intervention measures in ward areas according to the etiological pattern of YUSD. In July 2019, 47 families with YUSD were selected as case families and 23 families without YUSD were selected as control families in 31 natural villages of Heqing, Xiangyun, Yunlong, Eryuan, Jianchuan, Binchuan and Nanjian counties of Dali Prefecture. A unified questionnaire was used to investigate the basic information, economic status, dietary structure, and health literacy of the families during the two periods of "the first sudden death case" and "the present".Results:The annual household income of the case families at present (median, 20 492.6 yuan) was significantly higher than that of the first sudden death case (3 883.4 yuan), and the difference was statistically significant ( Z = - 5.27, P < 0.001). At present, rice (76.6%, 36/47) was the main diet of the case families; at the time of the first sudden death case, 23.4% (11/47) of the case families could not eat enough, and there was no such situation in the case families at present. Compared with the time of the first sudden death case, the dietary habits of the case families at present were as follows: the proportion of eating Trogia venenata decreased from 19.0% (39/205) to 0 (0/190), the proportion of eating wild fruit decreased from 17.1% (35/205) to 9.5% (18/190), and the proportion of drinking raw water decreased from 55.1% (113/205) to 42.1% (80/190), and the differences were statistically significant (χ 2 = 22.37, 4.90, 6.86, P < 0.05). Lifestyle and health awareness: the proportion of those who washed their hands before meals and after using the toilet increased from 9.8% (20/205) to 41.6% (79/190), those who did not overwork increased from 16.6% (34/205) to 34.2% (65/190), and those who took good protection when spraying pesticides increased from 7.3% (15/205) to 21.6% (41/190), and the differences were statistically significant (χ 2 = 53.17, 33.94, 16.48, P < 0.001). Toilet habits: the proportion of using outdoor toilet decreased from 75.6% (155/205) to 9.5% (18/190), the difference was statistically significant (χ 2 = 175.21, P < 0.001). When the first sudden death case occurred, the proportions of eating Trogia venenata and using outdoor toilet in the case families were higher than those in the control families (χ 2 = 22.37, 23.70, P < 0.001), the proportions of those who washed their hands before meals and after using the toilet and those who did not overwork in the case families were lower than those in the control families (χ 2 = 7.38, 4.93, P < 0.05). Conclusions:The economic conditions, production and living conditions of YUSD areas in Dali Prefecture have been significantly improved, and the health literacy and health prevention awareness of the population have been greatly improved. Economic conditions and living standard, dietary structure and health literacy may be related factors of YUSD.