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The COVID-19 pandemic is still ongoing in the world, the risk of COVID-19 spread from other countries or in the country will exist for a long term in China. In the routine prevention and control phase, a number of local COVID-19 epidemics have occurred in China, most COVID-19 cases were sporadic ones, but a few case clusters or outbreaks were reported. Winter and spring were the seasons with high incidences of the epidemics; border and port cities had higher risk for outbreaks. Active surveillance in key populations was an effective way for the early detection of the epidemics. Through a series of comprehensive prevention and control measures, including mass nucleic acid screening, close contact tracing and isolation, classified management of areas and groups at risk, wider social distancing and strict travel management, the local COVID-19 epidemics have been quickly and effectively controlled. The experiences obtained in the control of the local epidemics would benefit the routine prevention and control of COVID-19 in China. The occurrence of a series of COVID-19 case clusters or outbreaks has revealed the weakness or deficiencies in the COVID-19 prevention and control in China, so this paper suggests some measures for the improvement of the future prevention and control of COVID-19.
Subject(s)
Humans , COVID-19/prevention & control , China/epidemiology , Contact Tracing , Epidemics/prevention & control , Pandemics/prevention & control , SARS-CoV-2ABSTRACT
Objective: To analyze the course of disease and epidemiological parameters of COVID-19 and provide evidence for making prevention and control strategies. Methods: To display the distribution of course of disease of the infectors who had close contacts with COVID-19 cases from January 1 to March 15, 2020 in Guangdong Provincial, the models of Lognormal, Weibull and gamma distribution were applied. A descriptive analysis was conducted on the basic characteristics and epidemiological parameters of course of disease. Results: In total, 515 of 11 580 close contacts were infected, with an attack rate about 4.4%, including 449 confirmed cases and 66 asymptomatic cases. Lognormal distribution was fitting best for latent period, incubation period, pre-symptomatic infection period of confirmed cases and infection period of asymptomatic cases; Gamma distribution was fitting best for infectious period and clinical symptom period of confirmed cases; Weibull distribution was fitting best for latent period of asymptomatic cases. The latent period, incubation period, pre-symptomatic infection period, infectious period and clinical symptoms period of confirmed cases were 4.50 (95%CI:3.86-5.13) days, 5.12 (95%CI:4.63-5.62) days, 0.87 (95%CI:0.67-1.07) days, 11.89 (95%CI:9.81-13.98) days and 22.00 (95%CI:21.24-22.77) days, respectively. The latent period and infectious period of asymptomatic cases were 8.88 (95%CI:6.89-10.86) days and 6.18 (95%CI:1.89-10.47) days, respectively. Conclusion: The estimated course of COVID-19 and related epidemiological parameters are similar to the existing data.
Subject(s)
Humans , COVID-19 , Cohort Studies , Contact Tracing , Incidence , Prospective StudiesABSTRACT
Group 3 innate lymphoid cells (ILC3) as a family member of innate lymphoid cells (ILCs), have been defined as novel innate immune cells in the past decade. ILC3 include a variety of heterogenous subsets with different phenotypes and functions, which are mainly distributed in barrier organs such as the intestine, lung and skin. They play an important role in immune regulation, tissue repair and lymphoid tissue formation. However, in various inflammatory diseases, ILC3 become dysregulated and participate in the pathogenesis through secreting a series of cytokines such as interleukin (IL)-17, IL-22, interferon-γ (IFN-γ) and granulocyte-macrophage colony-stimulating factor (GM-CSF) to modulate other immune cells and induce the formation of ectopic lymphoid structures. Therefore, it is of great significance to explore the phenotype and function of ILC3 in order to advance the understanding of inflammatory diseases and find new therapeutic targets. In this article, the phenotypic characteristics, biological functions and research progress of ILC3 in inflammatory diseases were reviewed.
Subject(s)
Cytokines , Immunity, Innate , Interferon-gamma , Intestines , LymphocytesABSTRACT
Objective To improve the national surveillance plan on bacillary dysentery and to increase the sensitivity of the surveillance system on the disease. Methods Data was collected through China Disease Reporting Information System (CDRIS) and National Sentinel Surveillance Sites on bacillary dysentery. Data from the CDRIS was compared with the data from the National Sentinel Surveillance to identify the exiting problems. Results Data from the monitoring sites showed that the detection rate of infant cases of bacillary dysentery infection was 1%,less than that of other age groups. The highest rates were seen in children aged 3 through 9 years. Rate on misdiagnosis in all age group was 23.38%,when using the surveillance case definition of clinical cases and suspect case. The rate of misdiagnosis on infant cases of bacillary dysentery infection by clinical diagnosis was 50%. It showed that Shigella flexneri and Shigella sonnei were dominant with the positive rates as 57.21% and 42.41%,respectively. From the national sentinel surveillance sites,the confirmed cases taking up 43.39% which did not match the figure from the CDRIS. Conclusion The diagnostic criterion for bacillary dysentery fit well on other age groups in surveillance system except on infants. Active surveillance on bacillary dysentery that combining both clinical and laboratory diagnosis seems quite necessary on CDRIS,especially for infants.
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Objective To understand the infection status of pandemic 2009 H1N1 influenza after the first epidemic wave and to estimate the infected population. Methods Multi-stage stratified random sampling was introduced with 4500 subjects chosen in Guangdong province. 1500 people were selected from 5 districts (3 streets were selected in every district) in Guangzhou city which was representing the large cities. 1500 people were respectively selected from medium-sized city and rural areas, including 20 cities (1 county or district was selected in every city, at least 1 street or town was selected in every county or district respectively and then 1-2 residential area or county was selected in every street or township, respectively). Every sample was selected in accordance with the principle of random sampling, excluding those who had injected with novel H1N1 vaccine. We used hemagglutination inhibition test to understand the serum antibody level of novel H1N1, with title of 1∶40 as positive. Results A number of 4319 specimens, distributed in 21 cities, 25 counties, 85 streets or townships, 144 residential areas, were tested, with an overall positive rate as 22.82% (985/4319). The positive rate of those who had no symptoms of cold since June was 23.47% (471/2007).The positive rate of those who had fever, cough or sore throat was 26.25% (714/2720). The positive rate of those who had influenza-like illness (ILI) was 29.69% (337/1135 ). Conclusion The infection rate in the first epidemic wave of the novel influenza A (H1N1) pandemic in Guangdong province was 22.82%(985/4317). Based on the number of residonts in Guangdong province, the number of natural was estimated to have reached 21.78 million.
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Objective To study the status of norovirus in environment of the patient's residence and water samples after a norovirus gastroenteritis outbreak, to provide evidences for the development of strategies for prevention and control of the disease. Methods After a norovirus gastroenteritis outbreak, anus swabs from the patient, swabs from the household environment and the water samples were collected to detect the norovirus by RT-PCR methods. Sequencing analysis was conducted on those positive specimens. Results Three specimens of the anus swabs from 9 patients and 2 samples of the 46 house environment swabs were positive to the virus. The latter were from the surface of water-closets of two families that the illness were asymptomatic. Among 5 water samples, only one was positive, which was the rivulet water that the feces of the villagers evacuated directly. Results showed that the sequences of the virus detected from the anus swabs of the patients, the swabs from the household environment and the samples of the rivulet water belonged to the same species. Conclusion It is necessary to strengthen activities as supervision and disinfection to the feces of the patients, especially on monitoring the feces that might have contaminated the water during the noroviru gastroenteritis outbreak.
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<p><b>OBJECTIVE</b>Through systematic monitoring of the number and strain types of O1 and O139 Vibrio cholerae in the Pearl River estuary waters to analyze it's relevance with the temperature of environment, and the relevance between strains in water and isolates during outbreaks and epidemics as well as to estimate the methods used for environmental water detection and the potential role in cholera surveillance program.</p><p><b>METHODS</b>Twenty-four stations along the Pearl River were selected and the water samples were collected monthly from March 2006 to February 2007. V. cholerae O1 and O139 strains were isolated from the samples. Real-time PCR established in our laboratory was used to detect V. cholerae O1 and O139. Air temperature and water temperature were collected during sampling. Pulsed field gel electrophoresis (PFGE) was applied in molecular typing of the isolates.</p><p><b>RESULTS</b>862 water samples were collected during the study period. A total number of 77 O1 and O139 V. cholerae were isolated in 67 water samples and the positive rates were 7.77% for isolation and 26.33% for real-time PCR. Seasonal trend of positive rates by month were approximately coincident with the change of water temperature. The positive rates in the stations in urban area were higher than those in other areas. Toxigenic O139 strains were found in one station located in downstream of a marine market. Most of the O1 and O139 isolates were non-toxigenic. No trend of seasonal variation of the strains was noticed. Within these 75 isolates, 49 PFGE patterns were identified and the patterns differed widely with the similarity of 57.4% - 100%.</p><p><b>CONCLUSION</b>V. cholerae existed as the natural habitat in estuary water of the Pearl River and showed obvious genetic diversity. Data from monitoring waters might show the separation of strains with certain seasonal association. But the crowd did not show the relationship between the infections. Results from water surveillance program might provide indicators on the appearance of cholera pathogen which might be used in assessing the environmental risk of cholera epidemics as well as the alert of cholera.</p>
Subject(s)
Electrophoresis, Gel, Pulsed-Field , Environmental Monitoring , Phylogeny , Polymerase Chain Reaction , Seasons , Temperature , Vibrio cholerae O1 , Classification , Genetics , Vibrio cholerae O139 , Classification , GeneticsABSTRACT
<p><b>INTRODUCTION</b>Based on the estimate results of the capacity and preparedness of Beijing hospitals to respond to pandemic influenza, using flu surge model to evaluate its applicable hypothesis and to provide government with sentient strategy in planning pandemic influenza. Through collection of medical resources information, we calculated the possible impaction on hospitals by Flu Surge model and explored the applicable hypothesis in model operation through a questionnaire, direct observation and group discussion in 3 hospitals in Beijing. Based on flu surge model estimation during a 6-week epidemic from a pandemic virus with 35% attack rate, Beijing would have had an estimation of 5 383 000 influenza illnesses, 2 691 500 influenza outpatients, 76 450 influenza hospitalizations and 14 508 excess deaths. For a 6-week period with 35% attack rate, there would be a peak demand for 8% of beds, 210% of ICU beds, and 128% of ventilators estimated. Outpatients in different level hospital were quite disproportionated with 1742/ hospital/day, 650/hospital/day, and 139/hospital/day respectively. The sampled health workers had a mastery of 63.4% of the total knowledge and skills of diagnosing and treating of influenza, 73.5% of them washed their hands and 63.5% used PPE correctly. The total beds capacity, medical beds capacity and respiratory medical beds capacity would increase 8%, 35% and 128% respectively.</p><p><b>CONCLUSION</b>The estimation results could be referenced when planning the pandemic strategy, but the results should be treated objectively when considering the hypothesis and practical situation in this model being used.</p>
Subject(s)
Adolescent , Adult , Aged , Child , Child, Preschool , Female , Humans , Infant , Infant, Newborn , Male , Middle Aged , Young Adult , Disease Outbreaks , Hospital Bed Capacity , Hospital Planning , Hospitalization , Influenza, Human , Epidemiology , Models, Statistical , Surge CapacityABSTRACT
Objective To analyze the etiologic characteristics of Vibrio cholerae in Guangdong province in 2007.Genetic relationship was observed including among predominated biotype isolates from different areas within the province and among same biotypes isolates from cholera cases and regular surveillance.Methods Isolates from cholera cases and through environmental surveillance were typed by sero-and phage-typings.Similarity of molecular fingerprinting was analyzed through comparing the pulsed field gel electrophoresis(PFGE)pattern of predominated biotype isolates,and those of the same biotype isolates from cholera cases and environment surveillance,respectively.In addition,genetic relationship was determined by clustering analysis,using bionumerics software.Results In total,31 isolates from cholera cases were collected and subtyped for 3 serogroups.V.cholerae O1 El Tor Inaba phage 1d was the predominant biotype which causing most of the cases in Guangdong province in 2007.Data from cluster analysis showed that the similarity among Inaba phage 1d strains from different areas were from 94.5% to 100%.However.16 isolates were collected from environment surveillance programs and the predominated biotype could not be found.Additionally,the biotype distribution of cases isolates was not consistent with those isolates through surveillance.High phylogenetic diversity was observed for the same biotypes isolates from cases and surveillance samples.Conclusion Our data showed that V.cholerae O1 El Tor Inaba phage 1d was the predominated biotype with multi-clone coexisting and circulating in Guangdong province in 2007.It also appeared to be the characteristics of cholera in the non-epidemic period,suggesting that it was necessary to enhance the alert surveillance programs for cholera epidemic based on the molecular typing techniques.
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<p><b>OBJECTIVE</b>To understand the pollution rates of vibrio cholera (V. cholera) in different seafood, aquatic products and their circulatory processes, so as to help making measures for cholera control and prevention.</p><p><b>METHODS</b>Different seafood, aquatic products and breed water specimen collected from 12 provinces of China were tested from July to September in 2005.</p><p><b>RESULT</b>A total of 12 104 samples of seafood and aquatic products were tested and the average pollution rate of vibrio cholera was 0.52%. The positive isolate rate of turtle sample (1.72%) was the highest among all samples. The second higher isolated rate was 1.14% in water specimen of turtle breed pool. The positive rate of bullfrog was 0.50%. The percentage of toxin strains was 47.54% and 79.31% of them were isolated from turtle and water samples of turtle breed pool. The important sector of the pollution of vibrio cholera was in turtle breed pool (2.38%).</p><p><b>CONCLUSION</b>The average pollution rate of vibrio cholera in seafood and aquatic products in 12 provinces of China was low. It should be very necessary to supervise the sanitation in turtle breed for controlling and preventing the vibrio cholera.</p>
Subject(s)
Animals , Female , Male , China , Fishes , Microbiology , Food Contamination , Seafood , Microbiology , Seawater , Turtles , Microbiology , Vibrio choleraeABSTRACT
<p><b>OBJECTIVE</b>To develop a real-time SYBR Green polymerase chain reaction (PCR) for detection of Vibrio cholerae serogroups O1 and O139, and to evaluate its reliability through detection of estuary water samples.</p><p><b>METHODS</b>O antigen rfb genes specific for O1 and O139 were used for the design of PCR primers. The real-time SYBR Green PCR system in detecting O1 and O139 specific rfb genes in one tube was developed, and its sensitivity, specificity and reproducibility were evaluated. The ability of the real-time PCR in detection of estuary water samples was compared with the routine PCR and bacteria isolation.</p><p><b>RESULTS</b>The amplification of O1 or O139 specific target gene could be detected according to the melt curve temperature of amplicons. No amplification was observed in the templates of other 10 non-cholerae vibrios. When comparing to the real-time PCR to bacteria isolation in detection of 524 estuary water samples, it showed high sensitivity, plus also positive in real-time PCR detection among all the samples in which bacteria of O1 or O139 were isolated.</p><p><b>CONCLUSION</b>The real-time SYBR Green PCR could be used as the first step of rapid environment screen of V. cholerae in water samples thus might enhance the efficiency of isolation in screening of large amount of water samples.</p>
Subject(s)
Environmental Monitoring , Methods , Genes, Bacterial , Polymerase Chain Reaction , Methods , Reproducibility of Results , Rivers , Microbiology , Sensitivity and Specificity , Vibrio cholerae O1 , Vibrio cholerae O139ABSTRACT
<p><b>OBJECTIVE</b>To investigate the serologic type, phage-biotype and toxic factor of Vibrio cholerae isolated from different sea products, analyze the relation between the Vibrio cholerae in sea products and cholera epidemiology, and provide references for forecasting cholera epidemic situation and drawing out a preventing plan.</p><p><b>METHOD</b>The biotype of strains isolated was analyzed by using type and phage-biotype serological methods. The toxic gene was detected by PCR.</p><p><b>RESULTS</b>The constituent ratio of V. cholerae O139, Ogawa and Inaba were, respectively, 48.44%, 20.31% and 31.25% in 64 strains of V. cholerae. The result of phage-biotype showed that the 26 strains of V. cholerae O1 were all non-epidemic strains. The result of toxic gene detecting showed that positive rate of V. cholerae O139 was higher than those of Ogawa and Inaba.</p><p><b>CONCLUSION</b>The positive rate of toxic gene in V. cholerae O139 was high and the V. cholerae O139 was mainly in turtle, breed aquatics water and crustacean, so these sea products were the important sectors in cholera prevention and control.</p>
Subject(s)
Animals , Bacteriophage Typing , DNA, Bacterial , Genetics , Seafood , Microbiology , Serotyping , Vibrio cholerae , Classification , Genetics , Vibrio cholerae O1 , Vibrio cholerae O139ABSTRACT
<p><b>OBJECTIVE</b>To analyze the molecular types of Salmonella paratyphi A strains isolated in the recent years, and to construct the standard S. paratyphi A databank in the laboratory surveillance network PulseNet China.</p><p><b>METHODS</b>S. paratyphi A isolates from 4 provinces were analyzed with the standard pulsed-field gel electrophoresis (PFGE) protocol used in PulseNet and their patterns compared. The databank was constructed with BioNumerics.</p><p><b>RESULTS</b>Eleven PFGE patterns were obtained, in which 3 predominant patterns were identifies with a similarity coefficient of 96.3%. The strains of these patterns, accounted for 86.5% of the analyzed strains, appeared in different provinces and years.</p><p><b>CONCLUSION</b>The databank of S. paratyphi A was constructed and could be used in laboratory surveillance of S. paratyphi A in PulseNet China. From the analyses on molecular typing of the isolates, data suggested that the predominant strains might cause the epidemics in different regions.</p>