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Objective To assess the imported risk of COVID-19 in Guangdong province and its cities, and conduct early warning. Methods Data of reported COVID-19 cases and Baidu Migration Index of 21 cities in Guangdong province and other provinces of China as of February 25, 2020 were collected. The imported risk index of each city in Guangdong province were calculated, and then correlation analysis was performed between reported cases and the imported risk index to identify lag time. Finally, we classified the early warming levels of epidemic by imported risk index. Results A total of 1 347 confirmed cases were reported in Guangdong province, and 90.0% of the cases were clustered in the Pearl River Delta region. The average daily imported risk index of Guangdong was 44.03. Among the imported risk sources of each city, the highest risk of almost all cities came from Hubei province, except for Zhanjiang from Hainan province. In addition, the neighboring provinces of Guangdong province also had a greater impact. The correlation between the imported risk index with a lag of 4 days and the daily reported cases was the strongest (correlation coefficient: 0.73). The early warning base on cumulative 4-day risk of each city showed that Dongguan, Shenzhen, Zhongshan, Guangzhou, Foshan and Huizhou have high imported risks in the next 4 days, with imported risk indexes of 38.85, 21.59, 11.67, 11.25, 6.19 and 5.92, and the highest risk still comes from Hubei province. Conclusions Cities with a large number of migrants in Guangdong province have a higher risk of import. Hubei province and neighboring provinces in Guangdong province are the main source of the imported risk. Each city must strengthen the health management of migrants in high-risk provinces and reduce the imported risk of Guangdong province.
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Objective To analyze the clinical courses and outcomes of COVID-19 cases and the influencing factors in Guangdong province and provide basis for the formulation or adjustment of medical care and epidemic control strategy for COVID-19. Methods We collected demographic data, medical histories, clinical courses and outcomes of 1 350 COVID-19 patients reported in Guangdong as of 4 March 2020 via epidemiological investigation and process tracking. Disease severity and clinical course characteristics of the patients and influencing factors of severe illness were analyzed in our study. Results Among 1 350 cases of COVID-19 cases in Guangdong, 72 (5.3%) and 1049 (77.7%) were mild and ordinary cases, 164 (12.1%) were severe cases, 58 (4.3%) were critical cases and 7 (0.5%) were fatal. The median duration of illness were 23 days ( P 25 - P 75 : 18-31 days) and the median length of hospitalization were 20 days ( P 25 - P 75 : 15-27 days). For severe cases, the median time of showing severe manifestations was on the 12th day after onset ( P 25 - P 75 : 9th to 15th days), and the median time of severe manifestation lasted for 8 days P 25 - P 75 : 4-14 days). Among 1 066 discharged/fetal cases, 36.4% (36/99) and 1.0% (1/99) of the mild cases developed to ordinary cases and severe cases respectively after admission; and 5.2% (50/968) and 0.6% (6/968) of the ordinary cases developed to severe cases, and critical cases respectively after admission. In severe cases, 11.4% developed to critical cases (10/88). The influencing factors for severe illness or worse included male (a HR =1.87, 95% CI : 1.43-2.46), older age (a HR =1.67, 95% CI : 1.51-1.85), seeking medical care on day 2-3 after onset (a HR =1.73, 95% CI : 1.20-2.50) pre-existing diabetes (a HR =1.75, 95% CI : 1.12-2.73) and hypertension (a HR =1.49, 95% CI : 1.06-2.09). Conclusions The course of illness and length of hospitalization of COVID-19 cases were generally long and associated with severity of disease clinical outcomes. The severe cases were mainly occurred in populations at high risk. In the epidemic period, classified management of COVID-19 cases should be promoted according to needs for control and prevention of isolation and treatment for the purpose of rational allocation of medical resources.
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Objective To investigate the ability of linked color imaging(LCI)for diagnosing Helicobacter Pylori(Hp)infection compared with conventional white light imaging(WLI). Methods We prospectively collected subjects who underwent gastroscopy. Images under both WLI and LCI were recorded and analyzed. Software was used to measure pixel brightness for red(R),green(G),blue(B)of endoscopic images from suspected lesion sites. Biopsies were taken from these sites and Warthin-Starry silver staining was used to detect if Hp was present. R/(G+B)value was used to construct receiver operating characteristic curve(ROC)to predict Hp infec-tion and the area under curve(AUC),cut-off point,sensitivity,as well as specificity were calculated with the patho-logy as the gold standard. Results Forty-seven subjects(23 men,24 women;23 Uygur subjects,24 Han subjects) were included in a mean age of 49 years old. Ninety-one biopsies were obtained. Forty-four biopsies (48.4%)were Hp positive according to the pathology. The AUC of LCI was 0.616,with the cut-off point at 0.967 and sensitivity at 0.955 and specificity at 0.298. The AUC of WLI was 0.529,with cut-off point at 2.638 and sensi-tivity at 0.455 and specificity at 0.766. The AUC of Han and Uygur subjects were 0.650 and 0.549 by LCI. The AUC of atrophy gastritis subjects and non-atrophy gastritis subjects were 0.628 and 0.603. Conclusion LCI was superior to WLI in predicting Hp infection. LCI may act as an objective and quantified endoscopic diagnostic meth-od in Hp infection.
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Objective To detect the positive rates of antibodies against avian influenza virus (AIV) subtypes H5, H6, H7 and H9 among people in poultry occupations in Guangdong province and to analyze the transmission of various subtypes of AIV from poultry to human contacts for the prevention and control of novel AIV infection in human beings.Methods Serum specimens were collected from 1066 peo-ple in poultry occupations ( occupational group) and 205 people not in poultry occupations ( non-occupational group) in 10 cities of Guangdong province.The inactivated AIV strains, isolated from poultry or environment of Guangdong province, were used as antigens to detect antibodies against AIV subtypes H5, H6, H7 and H9 by using the hemagglutination inhibition ( HI) assay.Results The positive rates of antibodies against AIV subtypes H5, H6, H7 and H9 carried by people from the occupational group were respectively 0.44%, 0%, 0.30%and 0.30%in 2013 and 1.08%, 0.0%, 0.0%and 0.27%in 2014.Only the anti-H9 anti-bodies were detected in serum samples collected form people in the non-occupational group in 2013 with a positive rate of 0.95%.No significant differences with the positive rates of anti-AIV antibodies were found between the occupational group and the non-occupational group.However, the geometric mean titer ( GMT) of anti-AVI antibodies in people from the occupational group was higher than that of the non-occupational group.Conclusion Although a grand spread of AIV from avian to human is not likely to happen yet, con-tacting with poultry is the risk factor for AIV infection in Guangdong population.A long-term surveillance of anti-AIV antibodies in serum should be strengthened among people in poultry occupations for the timely pre-vention and control of novel AIV outbreak.
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<p><b>OBJECTIVE</b>To understand the transmission mode of human infection with avian influenza A (H7N9) virus.</p><p><b>METHODS</b>Field epidemiological investigation was conducted for a family clustering of human infection with H7N9 virus in Hengxian county, Guangxi Zhuang Autonomous Region in February 2014. Two patients and their 82 close contacts were surveyed. The samples collected from the patients, environments and poultry were tested by using real time reverse transcriptase-polymerase chain reaction (rRT-PCR), and the samples from patients were used for virus isolation. The samples from 5 close contacts were tested with RT-PCR. The clinical data, exposure histories of the patients and the detection results of the isolates and their homology were analyzed.</p><p><b>RESULTS</b>Patient A became ill 4 days after her last exposure to poultry in Zhongshan, Guangdong province, and returned to her hometown in Hengxian 2 days after onset. Patient B was patient A's 5 years old son, who had no known exposure to poultry but slept with patient A for 4 days. He developed symptoms 4 days after last contact with his mother. Two strains of H7N9 virus were isolated from the two patients. The 2 isolates were highly homogenous (almost 100%) indicated by gene sequencing and phylogenetic tree. None of the other 81 close contacts developed symptoms of H7N9 virus infection.</p><p><b>CONCLUSION</b>Patients B was infected through close contact with patient A, indicating that avian H7N9 virus can spread from person to person, but the transmissibility is limited and non-sustainable.</p>
Subject(s)
Animals , Child, Preschool , Female , Humans , Male , China , Cluster Analysis , Contact Tracing , Family , Homozygote , Influenza A Virus, H7N9 Subtype , Genetics , Influenza, Human , Virology , Phylogeny , Poultry , Virology , Real-Time Polymerase Chain Reaction , SleepABSTRACT
Objective To understand the status of infection and epidemic trend of Dengue fever and Chikungunya in Guangdong.Methods Retrospective survey and literature review were used to obtain data on the incidence,etiology of Dengue and Chikungunya.Serological survey was conducted to detect the specific-antibodies in healthy individuals for both Dengue virus (DENV) and Chikungunya virus (CHIKV).Results Three epidemics of Dengue fever were observed during 1990-2012,with the annual incidence rates as 9.75/100 000 in 1995,1.76/100 000 in 2002 and 1.25/100 000 in 2006,respectively.The predominant epidemic strains appeared to be DENV-2 and DENV-4 during 1990-1994.Since 1995,DENV-1 had become the predominant transmission strain which lasted for almost 13 years.Co-existence of multiple serotypes of DENV started in 2009.Of the 7 718 sera from healthy population during 2003-2012,180 specimens were detected positive for specific DENV-IgG antibody,ended with a sero-prevalence rate of 2.33％.All 2 132 sera in 2012 were detected negative for CHIKV-IgG antibody.Conclusion The overall exposure level to Dengue was considered to be low in Guangdong province.However,the predominant transmission mode caused by DENV-1 had been gradually changed into the co-existence of multiple serotypes with the endemic signs appeared in some part of the areas.Chikungunya was a newly emerging disease in Guangdong since local people were lack of basic immunity barrier.Surveillance and control programs thus seemed important.
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Objective To provide scientific evidence to identify and confirm severe acute respiratory syndrome (SARS) by laboratory detection.Methods Multiple clinical specimens were collected serially and systematically from the 4 suspected SARS patients, which occurred between Dec.2003 to Jan.2004 in Guangdong Province. The samples were tested by serologic and molecular methods.Results IgM or IgG antibodies against SARS-CoV were detectable after 6—8 days of the onset in four patients. The four-fold or greater rising in antibodies was clearly detected in three of the four patients, while the fourth patient’s seroconversion was from negative to positive. The results analysed by enzyme-linked immunosorbent assay( ELISA), immunoflourescence assay (IFA), and neutralization test were highly correlated. SARS-CoV RNA was just detected in 3 throat swab specimens from case 1 by real-time PCR. M, N and S genes were amplified by reverse transcriptase polymerase chain reaction (RT-PCR) from the positive samples. Sequencing results showed that they were SARS-CoV gene segments, and most closely matched SARS-CoV gene sequences were isolated from civet cats in Guangdong Province. Nevertheless, SARS-CoV was not isolated from any samples of the 4 patients.Conclusion Based on these results, the 4 reported cases were laboratorily confirmed as SARS cases.