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Objective An epidemiological investigation was carried out on the first family cluster epidemic of psittacosis in Wuhan to provide scientific basis for the prevention and control of Chlamydia psittacosis. Methods Epidemiological data were collected by field epidemiological investigation methods, and pathogenic testing was carried out by collecting cases, suspected exposed persons, and environmental samples. Results The 2 cases in the same family stared with fever, headache and chills. The first case was treated in 5 medical institutions and hospitalized in 2 of them. The results of metagenomic next-generation sequencing in the bronchoalveolar lavage fluid of the case indicated that it was infected with Chlamydia psittaci. Thirty environmental samples from cases and 3 pigeon farmers homes, 4 throat swabs from family members of pigeon farmers were collected, and 15 environmental samples were positive by real-time fluorescence quantitative polymerase chain reaction, all of which were in the cases' home and neighbor farmers' homes, including 8 pigeon feces smearing samples, 3 pigeon drinking residual water samples, 1 sand and corn eaten by pigeons, 1 tableware surface smearing sample, and 1 sample of external environment of the patient's home. Conclusions The family cluster epidemic of psittacosis was caused by exposure to the external environment contaminated by Chlamydia psittacosis. Poultry breeding should be regulated to prevent the spread of poultry infection to the human world. At the same time, the awareness of medical staff should be raised, and pathogenic testing should be carried out to confirm the diagnosis for avoiding the occurrence of severe cases and death.
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@#The epidemiological history and clinical characteristics of 7 cases of COVID-19 and 1 case of close contact in the first family aggregation epidemic of COVID-19 in Gansu Province were analyzed. The first patient A developed on January 22, 2020, with a history of residence in Wuhan, and confirmed severe cases of NCP on January 24, 2020; patient B, on January 23, 2020, diagnosed on January 31, severe cases; patient C, asymptomatic, diagnosed on January 27; patient D, asymptomatic, diagnosed on January 27; patient E, on January 24, diagnosed on January 28; patient F, asymptomatic, diagnosed on January 31; Patient G was asymptomatic and was diagnosed on January 31. In close contact, H was asymptomatic, PCR test was negative and asymptomatic, and he was discharged early. Among the 7 patients, 1 case died of (B) aggravation, and the other patients' condition was effectively controlled after active treatment. Except for the discharged cases, 5 cases were positive for COVID-19 specific IgM antibody and 1 case was negative. In this clustering outbreak, 4 patients remained asymptomatic, but PCR and IgM antibodies were positive, indicating that asymptomatic patients may be the key point to control the epidemic. Specific IgM antibody screening for patients whose pharyngeal swab nucleic acid test is negative but with ground glass-like lung lesions is very important for early detection and early isolation.
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Objective@#To report an investigation of a family cluster of coronavirus disease 2019 ( COVID-19 ) in Ningbo, so as to provide reference for the prevention and control measures.@*Methods@#According to the COVID-19 Prevention and Control Program ( fourth version ) , an epidemiological investigation was conducted to collect the demographic information, clinical features and exposure history, to find the close contacts, and to figure out the source and route of infection. @*Results@#Twelve confirmed cases and one asymptomatic case were reported. The attack rate was 16.05%. Among them, five were males and eight were females; the age ranged from 11 to 85 years old, with a median of 39 years old; most had mild symptoms. The incubation period was 2-13 days, with a median of 6.5 days. The first case ( Case 1 ) developed the symptoms on January 22, and had close contact with Zhang, an asymptomatic case, on January 20. Zhang was related to a cluster in the Buddhist assembly on January 19. Case 1, who caused the spread of the epidemic among family members, participated in several family visits and dinners from January 22 to 27 with other 24 families, resulting in six secondary cases and six third-generation cases. There were 54 close contacts except the family members, no infection was found. @*Conclusion@#This family cluster may result from the close contact with an asymptomatic case, and then spread within families through having dinners and living together.
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Objective@#To investigate the first family cluster of COVID-19 in Lanzhou, so as to provide basis for improving the COVID-19 outbreak prevention capacity. @*Methods @# On January 23, the First Hospital of Lanzhou University reported two suspected cases of COVID-19.According to the COVID-19 Epidemiological Investigation Plan ( second edition ) , general information, disease diagnosis and treatment, clinical symptoms, laboratory test results, household environment, exposure history and close contacts were collected to figure out the source of infection and routes of transmission. @*Results@#This family cluster lasted 29 days, from January 23 to February 21, reporting nine confirmed cases ( one death ) and one asymptomatic case. There were three imported cases from Wuhan, who were the source of the cluster; and seven secondary cases, who all had close contact with the imported cases during daily life or through having dinners. The secondary attack rate was 41.18% ( 7/17 ) . Among 9 confirmed cases, the incubation period ranged from four to ten days, with a median of nine days. Except for seven secondary cases, 24 close contacts were found and detected negative in the nucleic acid tests.@*Conclusions@#The first family cluster of COVID-19 in Lanzhou is caused by the imported cases from Wuhan. All the secondary cases have had dinners and/or had contact with the imported cases, thus they are infected through respiratory droplets and close contact.
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Objective@#To learn the epidemiological characteristics of family clusters of COVID-19 in Henan Province from January 23 to February 22, 2020, so as to provide reference for the prevention and control. @*Methods@#The data of family clusters of COVID-19 in Henan Province from January 23 to February 22 was retrieved from Public Health Emergency Management System, the epidemiological characteristics of time, space, population distribution and clinical feasures were analyzed. @*Results@#By February 22, there were 202 family clusters of COVID-19, with 546 cases reported in Henan Province, including 493 ( 90.29% ) confirmed cases and 53 ( 9.71% ) asymptomatic cases. There were 247 ( 45.24% ) imported cases and 299 ( 54.76% ) local cases. Most of the clusters were reported from January 25 to February 7, with 129 clusters accounting for 63.86% . The cases reported before February 5 were mainly imported ( 153 cases, 57.09% ) , after that local cases were predominant ( 168 cases, 68.29% ) . Eighteen cities in Henan Province all reported family clusters of COVID-19, with Xinyang, Zhengzhou, Nanyang, Zhumadian and Shangqiu as the top five. Most of the confirmed cases ( 430, 87.22% ) were mild. The median and longest incubation period was 8 and 17 days, respectively. The intergenerational distribution was dominated by first-generation and second-generation cases ( 537 cases, 98.35% ) . A total of 5 635 close contacts were tracked down, of whom 262 were secondary cases, with an incidence rate of 4.65%. The first cases of the family clusters were mainly imported from other provinces ( 149 cases, 73.76% ) .@*Conclusions @#The family clusters of COVID-19 in Henan Province were concentrated from January 25 to February 7. The source of infection mainly comes from other provinces. Most of the cases are first-and second-generation cases, with longer incubation period. Close contacts have higher incidence rate.
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The epidemiological history and clinical characteristics of 7 cases of COVID-19 and 1 case of close contact in the first family aggregation epidemic of COVID-19 in Gansu Province were analyzed. The first patient A developed on January 22, 2020, with a history of residence in Wuhan, and confirmed severe cases of NCP on January 24, 2020; patient B, on January 23, 2020, diagnosed on January 31, severe cases; patient C, asymptomatic, diagnosed on January 27; patient D, asymptomatic, diagnosed on January 27; patient E, on January 24, diagnosed on January 28; patient F, asymptomatic, diagnosed on January 31; Patient G was asymptomatic and was diagnosed on January 31. In close contact, H was asymptomatic, PCR test was negative and asymptomatic, and he was discharged early. Among the 7 patients, 1 case died of (B) aggravation, and the other patients' condition was effectively controlled after active treatment. Except for the discharged cases, 5 cases were positive for COVID-19 specific IgM antibody and 1 case was negative. In this clustering outbreak, 4 patients remained asymptomatic, but PCR and IgM antibodies were positive, indicating that asymptomatic patients may be the key point to control the epidemic. Specific IgM antibody screening for patients whose pharyngeal swab nucleic acid test is negative but with ground glass-like lung lesions is very important for early detection and early isolation.
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Objective To investigate epidemic characteristics of a family cluster of COVID-19, and to provide reference in improving the criteria for exclusion diagnosis and medical observation of close contacts. Methods Field epidemiological method was used to investigate the cases and close contacts of a family cluster of COVID-19 in Pudong New Area.Descriptive analysis was conducted on epidemiological data.Real-time fluorescence quantitative RT-PCR was used to detect 2019-nCoV nucleic acid in the respiratory tract specimens. Results There were two confirmed cases and one suspected case in the family cluster.The source of infection was Case 1 with a living history in Wuhan, Hubei Province.Case 2 and Case 3, as close contacts, received 14-day medical observation in a centralized isolation site.Case 2 showed symptoms 4 days after the onset of Case 1, and the diagnosis of COVID-19 was excluded after two negative nucleic acid tests during the isolation period.However, after the expiration of isolation, Case 2 was diagnosed positively for COVID-19 and Case 3 was suspected first and then excluded. Conclusion Daily close contact is critical for COVID-19 transmission and is the major cause of family clustering.Once the close contacts show symptoms, diagnosis should be made by combining the results of nucleic acid test, chest CT test, serological test, etc.We suggest to grade the risk of infection for close contacts, and to strengthen the standard of medical observation for close contacts with high risk of infection.
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The epidemiological history and clinical characteristics of 7 cases of COVID-19 and 1 case of close contact in the first family aggregation epidemic of COVID-19 in Gansu Province were analyzed. The first patient A developed on January 22, 2020, with a history of residence in Wuhan, and confirmed severe cases of NCP on January 24, 2020; patient B, on January 23, 2020, diagnosed on January 31, severe cases; patient C, asymptomatic, diagnosed on January 27; patient D, asymptomatic, diagnosed on January 27; patient E, on January 24, diagnosed on January 28; patient F, asymptomatic, diagnosed on January 31; Patient G was asymptomatic and was diagnosed on January 31. In close contact, H was asymptomatic, PCR test was negative and asymptomatic, and he was discharged early. Among the 7 patients, 1 case died of (B) aggravation, and the other patients' condition was effectively controlled after active treatment. Except for the discharged cases, 5 cases were positive for COVID-19 specific IgM antibody and 1 case was negative. In this clustering outbreak, 4 patients remained asymptomatic, but PCR and IgM antibodies were positive, indicating that asymptomatic patients may be the key point to control the epidemic. Specific IgM antibody screening for patients whose pharyngeal swab nucleic acid test is negative but with ground glass-like lung lesions is very important for early detection and early isolation.
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Objective@#To understand the possible transmission route of a family cluster of COVID-19 in Zhengzhou and the potential infectivity of COVID-19 in incubation period, and provide scientific evidence for the timely control of infectious source and curb the spread of the epidemic.@*Methods@#Epidemiological investigation was conducted for a family cluster of COVID-19 (8 cases) with descriptive epidemiological method, and respiratory tract samples of the cases were collected for the nucleic acid detection of 2019-nCoV by RT-PCR.@*Results@#Two primary cases, which occurred on 31 January and 1 February, 2020, respectively, had a common exposure history in Wuhan. The other six family members had onsets on 30 January, 31 January, 1 February (three cases) and 3 February, 2020.@*Conclusions@#In this family cluster of COVID-19, six family members were infected through common family exposure to the 2 primary cases. Five secondary cases had onsets earlier than or on the same day as the primary cases, indicating that COVID-19 is contagious in incubation period, and the home isolation in the early phase of the epidemic might lead to the risk of family cluster of COVID-19.
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Objective To investigate and analyze the epidemiological characteristics of epidemic hemorrhagic fever (EHF),and explore the causes and possible routes of transmission in Yingkou City for proposing prevention and control measures.Methods A case restropective investigation was done to all outbreak cases of EHF in Yingkou City,relevant epidemiological investigation,clinical examination and laboratory test were done.Search of case and new case were carried out in the population.Density of rats (night clip) and rate of rat infection (Hanta virus antigenemia) in the region of the epidemic area of EHF were investigated.Blood samples were collected,antibody of EHF was detected with enzyme linked immunosorbent assay (ELISA).The rat lung was detected virus antigen using immunofluorescence.EHF diagnosis was based on Diagnostic Criteria for Epidemic Hemorrhagic Fever (WS 278-2008).Results The results of the case study showed that a family of three was infected with the same disease in one month.It was a family cluster of EHF.Of the three cases,one case was Seoul virus (SEO) positive and showed infection for rattus type.Totally 54 human serum samples from the case search in key groups were tested.Two cases were seropositive with IgG,through epidemiological investigation,all people were healthy.On physical examination they had no symptoms such as viral infection with fever,fatigue,symptoms of three red and pains of EHF.Two cases were determined latent infection.The patient's living and health conditions were very poor.The floor of indoor was soil,all of the things were placed in chaos in this family,there were many signs of rats and rat holes in the yard,and there were several rat holes around the wellhead.Rat density surveillance showed that cloth clip 108 times,effective clamp 105 times,4 rats were captured,and the density of rats was 3.81％.The density of rats exceeded the national standard of no more than 1％ of the residential area.All the rats were Rattus norvegicus.Detection of lung antigen was negative in rats by immunofluorescence.Conclusions This event is a family cluster of EHF caused by Rattus norvegicus.Rodent prevention and control,improving family conditions and environmental management are essential measures for blocking of the disease transmission and infection controlling.