Assessing the modification impact of vaccination on the relationship of the Discomfort Index with hand, foot, and mouth disease in Guizhou: A multicounty study.

BACKGROUND: Hand, foot, and mouth disease (HFMD) is a major public health issue in China while temperature and humidity are well-documented predictors. However, evidence on the combined effect of temperature and humidity is still limited. It also remains unclear whether such an effect could be modified by the enterovirus 71 (EV71) vaccination. METHODS: Based on 320,042 reported HFMD cases during the summer months between 2012 and 2019, we conducted a study utilizing Distributed Lag Non-Linear Models (DLNM) and time-varying DLNM to examine how China's HFMD EV71 vaccine strategy would affect the correlation between meteorological conditions and HFMD risk. RESULTS: The incidence of HFMD changed with the Discomfort Index in an arm-shaped form. The 14-day cumulative risk of HFMD exhibited a statistically significant increase during the period of 2017-2019 (following the implementation of the EV71 vaccine policy) compared to 2012-2016 (prior to the vaccine implementation). For the total population, the range of relative risk (RR) values for HFMD at the 75th, 90th, and 99th percentiles increased from 1.082-1.303 in 2012-2016 to 1.836-2.022 in 2017-2019. In the stratified analyses, Han Chinese areas show stronger relative growth, with RR values at the 75th, 90th, and 99th percentiles increased by 14.3%, 39.1%, and 134.4% post-vaccination, compared to increases of 22.7%, 41.6%, and 38.8% in minority areas. Similarly, boys showed greater increases (24.4%, 47.7%, 121.5%) compared to girls (8.1%, 28.1%, 58.3%). Additionally, the central Guizhou urban agglomeration displayed a tendency for stronger relative growth compared to other counties. CONCLUSIONS: Although the EV71 vaccine policy has been implemented, it hasn't effectively controlled the overall risk of HFMD. There's been a shift in the main viral subtypes, potentially altering population susceptibility and influencing HFMD occurrences. The modulating effects of vaccine intervention may also be influenced by factors such as race, sex, and economic level.

Cross-sectional study on the epidemiological investigation ability of professional staff from Centers for Disease Control and Prevention in Guizhou Province.

Introduction: This study aims to evaluate the qualifications and identify skill enhancement areas for epidemiological investigators in Centers for Disease Control and Prevention (CDCs) in Guizhou's, informing future training and policy initiatives to strengthen public health responses. Methods: A cross-sectional survey was conducted in August 2022, and an online, self-designed questionnaire on the Epidemiological Dynamic Data Collection platform was administered to evaluate the professional staff in CDCs. The responses were scored and presented using descriptive statistical methods, and the factors influencing the total score were analyzed by one-way ANOVA and linear regression. Results and discussion: A total of 1321 questionnaires were collected, yielding an average score of 14.86±3.49 and a qualification rate of 29.9%. The scoring rate of ability of individual protection and coordination in epidemic control was high (87.25%). Meanwhile, improvements in further training were needed in areas such as data analysis ability (23.67%), knowledge of site disinfection (40.40%), and epidemiological investigation skills (42.50%). No significant difference was observed between the scores of city and county CDCs, (t = 1.071, p =0.284). The effects of gender and age could be disregarded, and the experience in epidemiological work and training (including investigation on COVID-19 cases and contacts), educational background, and professional title partially explained the survey outcome (R Square of the linear regression model was 0.351). The survey indicated the need for additional well-trained epidemiologic investigators in Guizhou. Specified training was effective in improving epidemiologic investigation, and enhancement in data analysis ability and knowledge of field disinfection are recommended in professional staff cultivation.

Epidemiologic Characteristics of COVID-19 in Guizhou Province, China.

INTRODUCTION: At the end of 2019, the COVID-19 broke out, and spread to Guizhou province in January of 2020. METHODOLOGY: To acquire the epidemiologic characteristics of COVID-19 in Guizhou province, we collected data from 169 laboratory-confirmed COVID-19 related cases. We described the demographic characteristics of the cases and estimated the incubation period, serial interval and the effective reproduction number. We also presented two representative case studies in Guizhou province: Case Study 1 was an example of the asymptomatic carrier; while Case Study 2 was an example of a large and complex infection chain that involved four different regions, spanning three provinces and eight families. RESULTS: Two peaks in the incidence distribution associated with COVID-19 in Guizhou province were related to the 6.04 days (95% CI: 5.00 - 7.10) of incubation period and 6.14±2.21 days of serial interval. We also discussed the effectiveness of the control measures based on the instantaneous effective reproduction number that was a constantly declining curve. CONCLUSIONS: As of February 2, 2020, the estimated effective reproduction number was below 1, and no new cases were reported since February 26. These showed that Guizhou Province had achieved significant progress in preventing the spread of the epidemic. The medical isolation of close contacts was consequential. Meanwhile, the asymptomatic carriers and the super-spreaders must be isolated in time, who would cause a widespread infection.

Epidemiological Investigation and Etiological Analysis of a Cutaneous Anthrax Epidemic Caused by Butchering Sick Cattle in Guizhou, China.

A suspected human cutaneous anthrax epidemic caused by butchering sick cattle occurred in Zhijin County of Guizhou Province, Southwest of China, in 2016. Epidemiological investigation and etiological analysis were performed to provide a scientific basis for the source tracking of the epidemic. The epidemic was epidemiologically investigated, and skin blister samples collected from patients and soil samples collected from the butchering spots were used for Bacillus anthracis isolation. The suspicious B. anthracis isolates were identified using conventional methods and PCR, followed by genotyping using multiple-locus variable-number tandem repeats (VNTRs) analysis (MLVA-15) and canonical single-nucleotide polymorphism (canSNP). The genetic relationship of epidemic strains and isolates collected from other regions was analyzed. Epidemiological investigation results showed that the patients may be infected by B. anthracis during butchering sick cattle. Two suspected B. anthracis strains were isolated from blood samples and blister fluids, respectively. Conventional methods identified the two suspected isolates as B. anthracis, while PCR results showed that anti-protective antigen (PA) and capsule (CAP) gene were positive in the two isolates. MLVA-15 showed that the MLVA profiles of the two isolates were 9-20-12-53-16-2-8-8-8-4-4-4-4-10-4, which is different from the MLVA profiles of representative strains from other regions. CanSNP analysis showed that the two strains belonged to cluster A.Br.001/002. Clustering analysis and minimum spanning tree (MST) demonstrated that the two isolates were clustered with strains previously isolated from Guizhou Province. The results indicated that B. anthracis was the pathogen for this epidemic, and the patients were infected during butchering the sick. The genetic characteristics and the relationship of the B. anthracis isolates to strains from other regions indicated that the epidemic was a local occurrence.

Correction to: Genetic characterization of Bacillus anthracis in Guizhou Province, Southwest of China.

ERRATUM: Upon publication of the original article (1) it was highlighted by the authors that a grant awarded to support the research work of the study was missed in the acknowledgements. It should also be acknowledged that the grant titled "Genotyping and Molecular Epidemiological Characteristic of Bacillus anthracis in Guizhou Province" awarded by the Program of Natural Science Foundation of Guizhou Province (Grant No. Qian Ke He J Word [2015] 2084)also contributed to the resources for this research. This has since been formally noted in this correction article.

[Investigation on the causes of increased hepatitis E cases reported in Guizhou province].

OBJECTIVE: To analyze causes of growing hepatitis E (HE) cases reported in Guizhou province, and probe into existing problems faced by medical institutions in diagnosis of clinical and laboratory-confirmed cases, for the purpose of improving the quality of HE surveillance system. METHODS: Six hospitals reporting greater HE cases from 2007 to 2011 were pinpointed, whose reported cases rose suddenly in 2011. Such cases were investigated by means of impatient medical record review, results of laboratory test and clinician interview. RESULTS: 136 of the 354 reported HE cases investigated were found compliant with the diagnostic criteria of HE with an accordance rate of 38.42%. Difference of the HE diagnostic accordance rate among individual years, hospitals and reporting departments was statistically significant. Such rate of hospital reports was found to be the lowest in 2011, ranging from 0 to 18.18% respectively; HE cases reported by non-infectious departments accounted for 61.30% of total cases reported, with its accordance rate considerably below the infectious departments (8.29%). HE positive cases and HE positive rate in 2011 were significantly higher than that of preceding years. CONCLUSION: Such increase of reported HE cases in 2011 in the province was mostly attributable to more HE laboratory tests made by the hospitals, yet the accordance rates were lower than satisfactory. In this regard, the medical institutions in question were advised to enhance their competency training for HE diagnosis and case report quality.

Genetic characterization of Bacillus anthracis in Guizhou Province, Southwest of China.

BACKGROUND: Bacillus (B.) anthracis is the pathogen that causes fatal anthrax. Guizhou Province is an old foci of anthrax in the southwest of China. Human anthrax has also been frequently reported in Guizhou in recent year. However, there is limited information on the genetic background of local B. anthracis isolates in Guizhou Province. Strain-specific detection of this bacterium using molecular approaches has enhanced our knowledge of microbial genetics. In the present study, we employed Multiple Locus Variable Number Tandem Repeats (VNTR) Analysis (MLVA) assay to analyze the genetic characteristics of B. anthracis strains isolated in Guizhou Province and their relationships to worldwide distributed isolates. RESULTS: A total of 32 isolates of B. anthracis from soil, human, cattle, dog and water of different anthrax epidemics in Guizhou Province from 2006 to 2011 were confirmed with phage lysis test, penicillin inhibition test and PCR. MLVA-8 discriminated them into 28 unique MLVA types (MT G1 - G28), which were novel MTs compared with the previous reports. Cluster tree based on 32 isolates from Guizhou Province and 76 worldwide distributed isolates (30 MTs) showed they were divided into three clusters, designated A, B and C. All the 32 isolates were distributed in cluster A, which were further grouped into A1, A2, A3 and A4 sub-clusters. 32 isolates from Guizhou Province were closely grouped in each of the sub-clusters, respectively. Minimum Spanning Tree (MST) based on the MLVA data showed that the 28 MLVA profiles of isolates from Guizhou Province and 30 MLVA profiles of worldwide distributed isolates formed three clonal complexes (CCs) and ten singletons. CONCLUSIONS: 28 novel MTs of B. anthracis from Guizhou were revealed and their relationships to worldwide isolates were showed. The results will provide important information for prevention of anthrax and also enhances our understanding of genetic characteristics of B. anthracis in China.

[Evaluation on the effects of prevention and control programs regarding typhoid fever and paratyphoid fever in Guizhou province, from 2007 to 2012].

OBJECTIVE: This study was to evaluate the effects of prevention and control regarding programs on typhoid fever and paratyphoid fever, in Guizhou province, from 2007 to 2012, to provide evidence for the improvement of related programs. METHODS: Data on typhoid fever and paratyphoid including information on epidemics, individual, cases, measures for prevention and control programs taken and relative government documents were collected and analyzed in Guizhou province, from 2007 to 2012. Information related to the average annual incidence, nature of outbreaks, time span before confirmed diagnosis was made, unit which carried the case report, proportion of laboratory confirmed diagnosed cases and case-management were compared between 2007-2009 and 2010-2012 descriptively while chi-square test with Excel and EpiInfo software were used for data analysis. RESULTS: In the period of 2007-2009, a total of 5 978 typhoid fever and paratyphoid fever cases were reported in Guizhou province with the average yearly incidence as 5.29/100 000. In the period of 2010-2012, 2 765 cases were reported with the average yearly incidence as 2.57/100 000. When compared to the former, data from the latter period showed that the average yearly incidence had declined 51.31% in all the prefectures. There were still some outbreaks appeared but the total number of cases involved reduced 87.50%. The time span before the confirmation of diagnosis became shorter but the difference was not statistically significant (χ² = 0.08, P = 0.99). Number of cases reported by hospitals at county or above had 11.51% of increase while those cases reported at the township hospitals or below decreased for 61.47% . The proportion of laboratory diagnosed cases increased 23.63%. Rates of timeliness on cards being filled in, input and audited showed increase of 8.44%, 6.76% and 2.40% respectively. CONCLUSION: Successful measures for prevention and control on typhoid fever and paratyphoid fever had been remarkably taken in Guizhou province, but the potential risk of outbreaks still existed in some areas, suggesting that health education and surveillance programs including laboratory diagnosis, should be strengthened.

[Fever monitoring program in areas with high incidence of typhoid and paratyphoid fever in Guizhou province].

OBJECTIVE: To understand the incidence rates of both typhoid fever and paratyphoid fever in the high prevalent areas of Guizhou province so as to provide evidence for the development of programs on comprehensive intervention and effectiveness evaluation. METHODS: Six townships in Pingba county were selected as intervention areas while six townships in Kaiyang county were taken as control. All hospitals and clinics were classified into A, B and C types according to its level and the capacity of the blood culture. Surveillance on typhoid and paratyphoid fever was conducted based on all population and all hospitals, clinics and county CDCs among the patients with unknown fever. RESULTS: In the surveillance area in those two counties, there were 12 944 blood samples from patients with unknown fever which have been tested and cultured. Among them, 200 strains of Salmonella including 16 typhoid strains, 184 paratyphoid A strains were identified, with the total positive rate as 1.55%. The positive rate before the intervention program was higher than the after. The detection rate was 1.91% in the type A hospitals. 39 strains of Salmonella have been cultured from 2039 samples which accounting for 19.50% (39/200) of the total strains. 4315 blood samples were cultured at the 'Class B' sites which isolated 82 strains of Salmonella, accounting for 41.00% (82/200), with a detection rate as 1.90%. 6590 samples were cultured at the 'Class C' sites, which identified 79 strains of Salmonella, accounting for 39.50% (79/200), with a detection rate as 1.20%. The detection rate was much higher before the use of antibiotics than after using them (P < 0.05). The annual peak time of positive detection was in spring and fall. The outbreaks or epidemics often appeared in the same places, with farmers, students as the high-risk populations. Symptoms of both typhoid and paratyphoid fever were not typical. CONCLUSION: Typhoid and paratyphoid monitoring programs which covered primary health care institutions in the high incidence area seemed to be effective in reflecting the pictures as well as the burden of both typhoid and paratyphoid.

Source tracking of human leptospirosis: serotyping and genotyping of Leptospira isolated from rodents in the epidemic area of Guizhou province, China.

BACKGROUND: Sustained human leptospirosis as well as death cases has been reported in Qiandongnan Prefecture, Southeast of Guizhou, China, recently, but these human patients were only clinically diagnosed, and leptospires have never been isolated from patients in these epidemic regions, In order to track the source of infection and understand the etiologic characteristic of leptospirosis, we performed rodent carrier surveillance for leptospirosis in the epidemic area in 2011. The population distribution of rodents in the epidemic regions was revealed. RESULTS: Four strains of leptospire were isolated from Apodemus agrarius. Microscopic agglutination test (MAT) confirmed the four isolates belonged to leptospiral serogroup Icterohaemorrhagiae. Multilocus sequence typing (MLST) indicated that all the four strains were defined as sequence type 1(ST1), which is identical to the three strains isolated from Rattus tanezumi in Rongjiang County in 2007. Clustering analysis of the MLST data indicated that the local isolates exactly matched with reference strain of leptospiral serovar Lai strain 56601, which is consistent with anti-Leptospira antibody detection of patients using MAT. CONCLUSIONS: Apodemus agrarius may be the potentially important carrier of leptospirosis and the potential source of leptospiral infection in human, and serovar Lai maybe the epidemic serovar of Leptospira in the localities.

A foodborne outbreak of Aeromonas hydrophila in a college, Xingyi City, Guizhou, China, 2012.

BACKGROUND: On 12 May 2012, over 200 college students with acute diarrhoea were reported to the Guizhou Center for Disease Control and Prevention. We conducted an investigation to identify the agent and mode of transmission and to recommend control measures. METHODS: A suspected case was a person at the college with onset of ≥ two of the following symptoms: diarrhoea (more than three loose stools in 24 hours), abdominal pain, vomiting or fever (> 37.5C) between 6 and 15 May 2012. A confirmed case also had a positive Aeromonas hydrophila culture from a stool sample. A retrospective-cohort study of 902 students compared attack rates (AR) by dining place, meals and food history. We reviewed the implicated premise, its processes and preparation of implicated food. RESULTS: We identified 349 suspected cases (AR = 14%) and isolated Aeromonas hydrophila from three stools of 15 cases. Students who ate in cafeteria A were more likely to be ill compared to those eating in other places (relative risk [RR]: 3.1, 95% confidence interval [CI]: 2.0-4.8). The cohort study implicated cold cucumber (RR: 2.6, 95% CI: 2.0-3.3) and houttuynia dishes (RR: 1.8, 95% CI: 1.4-2.3). Environmental investigation showed that vegetables were washed in polluted water from a tank close to the sewage ditch, then left at 30 °C for two hours before serving. The Escherichia coli count of the tank was well above the standard for drinking-water. CONCLUSION: This outbreak of Aeromonas hydrophila was most probably caused by salad ingredients washed in contaminated tank water. We recommended enhancing training of foodhandlers, ensuring tanks and sewerage systems comply with appropriate standards and adequate monitoring of drinking-water sources.