LTBI-negative close contacts of tuberculosis are more likely to develop the disease: enlightenment and lessons from a cluster outbreak.

Background: Tuberculosis (TB) prevention and control among groups living together, such as students, workers, older adults in nursing homes, and prisoners, present many challenges due to their particular age and environmental factors, which can make them more susceptible to TB clusters with significant societal impact. This study aimed to evaluate a TB cluster outbreak epidemic in a university and provide suggestions for improving TB control strategies for groups living together. Methods: Pulmonary TB screening and close-contact investigation were conducted using acid-fast staining, sputum culture, GeneXpert testing, tuberculin skin testing (TST), interferon-gamma release assay (IGRA), and chest computed tomography (CT). GraphPad Prism 9.5.1 was utilized for data analysis. Collected epidemic data were comprehensively analyzed by rate comparison. Results: The TB cluster outbreak epidemic was identified with an index case confirmed positive. The initial screening was conducted on potential close contacts of the index case, and the TST's positive rate (diameter ≥ 5 mm) and strong positive rate (diameter ≥ 15 mm) among these close contacts were 65.60% (21/32) and 34.40% (11/32), respectively. Moreover, the latent TB infection (LTBI) rate (diameter ≥ 10 mm) was 43.75% (14/32), and the IGRA's positive rate was 9.30% (3/32). Chest CT scans did not reveal any abnormalities. Surprisingly, 5 of the close contacts developed active TB in the second screening, accompanied by changes from negative to positive TST and/or IGRA results, after 3 months of follow-up. Accordingly, we expanded the screening scope to include another 28 general contacts. We found that the positive rate (78.00%, 25/32), strong positive rate (50.00%, 16/32), and LTBI rate (62.50%, 20/32) of the 32 close contacts were significantly higher than those of the additional general contacts (28.00%, 8/28; 14.3%, 4/28; 25.00%, 7/28), as indicated by p < 0.05. Conclusion: In the event of an epidemic TB outbreak, it is essential to rapidly identify the source of infection and initiate timely screening of close contacts. The initial screening should be focused on individuals without LTBI, who are at higher risk of developing TB. In purified protein derivative-negative individuals living in groups, additional vaccination or revaccination with Bacille Calmette-Guérin may help prevent cluster outbreaks of TB.

Risks of and response to cluster outbreak of imported malaria during malaria post-elimination era in China / 中国热带医学

@#Abstract: Objective　To analyze the recent cluster outbreaks of imported malaria and explore the risks, challenges and countermeasures for dealing with such events during malaria post-elimination era of malaria, and to provide reference for effectively addressing the risks and consolidating the achievements of malaria elimination. Methods　The individual malaria case data from "The Information System for Infectious Disease Surveillance" and "The Information System For Parasitic Diseases Prevention And Control" were collected，and the diagnosis classification, infection source, time and space distribution of cases were analyzed. Results　From January 1 to August 11, 2022, a total of 429 malaria cases were reported nationwide, an 18.9% decrease compared to the same period last year (529 cases), all of which were imported cases. The overall weekly trend of the outbreak remained stable, but since Week 31 (July 25-31), there has been a significant increase in the number of cases, with a peak on August 5. From July 25 to August 11, 2022, a total of 162 malaria cases were reported nationwide, up 315.4% from 39 cases in the same period last year, accounting for 37.8% of the total cases up to August 11, 2022. The main source of imported infections was Guinea (95 cases, 58.6%), with most cases reported in Longgang District, Shenzhen City, Guangdong Province (30 cases), Shilin County, Kunming City, Yunnan Province (21 cases), Chaoyang District, Beijing (11 cases), and Xiaoshan District, Hangzhou City, Zhejiang Province (7 cases). Conclusions　Due to the concentration of returnees to China, several entry port cities simultaneously experienced cluster outbreaks of imported malaria, which brought immense pressure and challenges to local medical and health institutions. Health facilities at all levels need to maintain high vigilance and sensitivity, be well prepared, and avoid death and secondary transmission caused by imported cases.

Analysis of epidemic characteristics of forty-two COVID-19 cluster outbreaks in Hangzhou / 上海预防医学

Objective To determine the epidemic characteristics of forty-two coronavirus disease 2019 （COVID-19） cluster outbreaks in Hangzhou city and provide scientific evidence for further prevention and control measures. Methods Data of the COVID-19 cluster outbreaks in Hangzhou were obtained from the National Public Health Emergency Management Information System. Epidemic characteristics were summarized by reviewing the epidemiological investigation reports. Results A total of forty-two COVID-19 cluster outbreaks were documented in Hangzhou in 2020， including 130 confirmed cases and 7 cases with asymptomatic infection. The majority occurred from January to February， 2020. Moreover， 92.86% （39/42） of the cluster outbreaks were familial transmission. The proportion of the cluster outbreaks involving 2 cases accounted for 54.7% （23/42）. In the secondary cases， family members accounted for 84.15% （69/82）. Conclusion The COVID-19 cluster outbreaks in Hangzhou mainly occur in families， and the majority of the secondary cases is family members.

Analysis of epidemic characteristics of forty-two COVID-19 cluster outbreaks in Hangzhou / 上海预防医学

Objective To determine the epidemic characteristics of forty-two coronavirus disease 2019 （COVID-19） cluster outbreaks in Hangzhou city and provide scientific evidence for further prevention and control measures. Methods Data of the COVID-19 cluster outbreaks in Hangzhou were obtained from the National Public Health Emergency Management Information System. Epidemic characteristics were summarized by reviewing the epidemiological investigation reports. Results A total of forty-two COVID-19 cluster outbreaks were documented in Hangzhou in 2020， including 130 confirmed cases and 7 cases with asymptomatic infection. The majority occurred from January to February， 2020. Moreover， 92.86% （39/42） of the cluster outbreaks were familial transmission. The proportion of the cluster outbreaks involving 2 cases accounted for 54.7% （23/42）. In the secondary cases， family members accounted for 84.15% （69/82）. Conclusion The COVID-19 cluster outbreaks in Hangzhou mainly occur in families， and the majority of the secondary cases is family members.

Pathogen identification and genotyping of two cluster outbreaks of herpangina in children in Dapeng New District， Shenzhen / 上海预防医学

ObjectiveTo determine the pathogenic characteristics and genotype of two outbreaks of herpangina in children in Dapeng New District， Shenzhen， in May 2021. MethodsA total of five throat swabs from children in the two outbreaks of herpangina were collected and examined for common enteroviruses by real-time PCR. The VP1 region was further amplified by nested RT-PCR. The CLUSTAL W program in MEGA7 software was used to conduct the alignment and reconstruct a phylogenetic tree. ResultsThe pathogen causing the 2 cluster outbreaks of herpangina was coxsackievirus A4 （CVA4）. The sequences of CVA4 VP1 genes revealed that a nucleotide identity of 92% between the strains in the two outbreaks. The three CVA4 strains isolated in kindergarten A had the closest phylogenetic relationship with that isolated in Shenzhen in 2018（MN840533）， with the nucleotide identity of 98.11%. The two strains in kindergarten B had the closest phylogenetic relationship with CVA4 strain isolated in Sichuan in 2018（MW178763）， with the nucleotide identity of 97.88%. The phylogenetic tree showed that all five CVA4 strains in this study belonged to the C2 genotype. ConclusionThe C2 genotype of CVA4 is the causative agent in both outbreaks of herpangina.

Prolonged SARS-CoV-2 RNA Shedding from Therapy Cat after Cluster Outbreak in Retirement Home.

We report a therapy cat in a nursing home in Germany infected with severe acute respiratory syndrome coronavirus 2 during a cluster outbreak in the home residents. Although we confirmed prolonged presence of virus RNA in the asymptomatic cat, genome sequencing showed no further role of the cat in human infections on site.

[Source investigation on a familiar cluster of coronavirus disease 2019 in Dandong city of Liaoning Province].

To Track the source of the infection through an investigation of a clustering of coronavirus disease 2019(COVID-19), and provide scientific basis and Strategy for the effective control of the aggregated epidemic situation of COVID-19. Field epidemiological method was used to survey the cases and related close contacts in a family clustering epidemic of COVID-19 in Dandong city of Liaoning Province. We obtained survey data for a descriptive analysis.Real time RT-PCR technique was used to detect 2019-nCoV nucleic acid in samples collected from cases and related close contacts combined with serum specific antibody detection. A total of 3 confirmed cases and 2 asymptomatic infection cases were discovered in the clustering epidemic, with 34 close contacts.Of eight close family contacts visiting from other province, one patient was on the same flight as the confirmed case, and her antibody IgG was positive. The family clustering was caused by past infection case who visited her friend through Wuhan from other provinces to local area.

The analysis of epidemiological characteristics of COVID-19 cases in Hebei Province / 公共卫生与预防医学

Objective To analyze the epidemiological characteristics of the novel coronavirus pneumonia epidemic in Hebei Province, and to provide a scientific basis for the prevention and control of the novel coronavirus pneumonia epidemic. Methods Descriptive epidemiological methods were used to analyze the epidemiological characteristics of all COVID-19 cases reported in Hebei Province from January 22, 2020 to September 22, 2020. Results As of September 22, 2020, a total of 365 confirmed cases had been reported in Hubei Province, including 339 local confirmed cases and 26 imported cases, of which 18 were critical cases, 34 severe cases, and 6 deaths. Among the confirmed cases, 198 were males and 167 were females, with a male to female ratio of 1.19:1. The epidemic situation in Hebei Province can be divided into three stages: The first stage (January 22 to April 6) was dominated by imported cases from Hubei Province, with 318 reported cases, accounting for 87.12% of the total cases, and the mortality rate was 1.89%; The second stage (June 14 - July 25) was the spread caused by cases in Beijing Xinfadi market, with 21 cases reported, accounting for 5.75% of the total cases, and the mortality rate was 0%; The third stage (July 26 - September 22) was mainly imported cases from abroad, with 26 cases reported, accounting for 7.12% of the total cases, and the mortality rate was 0%. Conclusion The COVID-19 epidemic situation in Hebei Province has been under control. In view of the continuous spread of the epidemic situation in foreign countries, it is extremely important to strictly prevent the import of overseas epidemics and prevent the outbreak from rebounding.

[Analysis on the cluster epidemic of coronavirus disease 2019 in Guangdong Province].

Objective: Analysis of clustering characteristics of coronavirus disease 2019 (COVID-19) in Guangdong Province. Methods: The COVID-19 cases in Guangdong Province onset from January 1 to February 29, 2020 were collected from Chinese information system for disease control and prevention and Emergency Public Reporting System. Obtain the epidemiological survey data of the cluster epidemic situation, and clarify the scale of cluster epidemic situation, the characteristics of the index cases, family and non-family subsequent cases. Calculate serial interval according to the onset time of the index cases and subsequent cases, secondary attack rate based on the close contacts tracking results, the characteristics of different cases in the clustered epidemic were compared. Results: A total of 283 cluster were collected, including 633 index cases, 239 subsequent cases. Families are mainly clustered, the total number involved in each cluster is in the range of 2-27, M (P25, P75) are 2.0 (2.0, 4.0). During January 15 to February 29, the secondary attack rate is 2.86% (239/8 363) in Guangdong Province, the family secondary attack rate was 4.84% (276/3 697), and the non-family secondary attack rate was 1.32% (61/4 632). According to the reporting trend of the number of cases in Guangdong Province, it can be divided into four stages, the rising stage, the high platform stage, the descending stage and the low level fluctuation period. The secondary attack rate of the four stages were 3.5% (140/3 987), 2.3% (55/2 399), 2.6% (37/1 435), 1.3% (7/542), respectively. The difference was statistically significant (P=0.003). Conclusion: COVID-19 cluster mainly occurs in families in Guangdong Province. The scale of the clustered epidemic was small; the serial interval was short; and the overall secondary attack rate was low.

Epidemiological and genetic investigation of a cluster of cases of severe fever with thrombocytopenia syndrome bunyavirus.

BACKGROUND: To analyze and discuss the transmission route of a cluster of cases of severe fever with thrombocytopenia syndrome bunyavirus (SFTSV). METHOD: We performed an epidemiological investigation and a genetic analysis of patients with severe fever with thrombocytopenia syndrome (SFTS) caused by SFTSV, their close contacts and the surrounding population. RESULTS: We found that all patients had contact with the blood of the first patient. The comparison of gene sequences in the three isolated SFTSV strains showed that the strains were closely related. Six close contacts and nine individuals in the surrounding population were positive for SFTSV IgM antibody. CONCLUSION: We suspect that the cluster outbreak was transmitted via blood and that the natural reservoir host of SFTSV exists in the patients' environment.