[Effect of Low-Dose Recombinant Interleukin-2 Therapy on Immunocyte Subsets in Children with Solid Tumor].

OBJECTIVE: To evaluate the effect of low-dose recombinant interleukin-2 (rIL-2) therapy on immunocyte subsets and its side effects in children with solid tumor. METHODS: A total of 22 children (11 males and 11 females) with solid tumor in our department from December 2012 to November 2017 were selected, with a median age of 9 (3-16) years old when starting IL-2 therapy. ALL surgeries and chemotherapy of children had been completed before low-dose rIL-2 therapy, and 17 cases achieved complete remission (CR) and 5 cases achieved partial remission (PR). A low-dose rIL-2 therapy was given 1 month after chemotherapy for 1 year: 4×105 IU/(m2·d), s.c. for every other day, 3 times per week. The immunocyte subsets were detected every 3 months until the end of treatment, meanwhile, disease condition and therapy-related side effects were followed up. RESULTS: After low-dose rIL-2 therapy in 22 children, the absolute values of CD3+ T cells, CD3-CD56+ natural killer cells, CD3+CD4+ helper T cells (Th) and CD3+CD8+ cytotoxic T cells were up-regulated remarkably, as well as Th/suppressor T cells (all P < 0.05). While, there were no significant differences in absolute value and proportion of CD4+CD25+CD127- Treg cells during therapy. Among the 17 children who achieved CR before rIL-2 therapy, 14 cases continued to maintain CR after therapy, while 3 cases relapsed, and with 2 died after treatment abandonment. The 5 children who achieved PR before low-dose rIL-2 therapy were evaluated CR by PET/CT scan after treatment. In the early stage of low-dose rIL-2 therapy, 1 child developed skin rashes at the injection sites, and 2 children ran a slight to mild transient fever. Their symptoms disappeared without any organ damage after symptomatic treatment. CONCLUSION: Low-dose rIL-2 therapy has good drug tolerance, and changes the distribution of anti-tumor immune-cell subgroup in peripheral blood of children with solid tumor remarkably without up-regulation of absolute value and ratio of Treg cells.

Tracking tumor alteration in glioma through serum fibroblast activation protein combined with image.

PURPOSE: Detecting tumor progression of glioma continues to pose a formidable challenge. The role of fibroblast activation protein (FAP) in gliomas has been demonstrated to facilitate tumor progression. Glioma-circulating biomarkers have not yet been used in clinical practice. This study seeks to evaluate the feasibility of glioma detection through the utilization of a serum FAP marker. METHODS: We adopted enzyme-linked immunosorbent assay (ELISA) technique to quantify the relative FAP level of serum autoantibodies in a cohort of 87 gliomas. The correlation between preoperative serum autoantibody relative FAP levels and postoperative pathology, including molecular pathology was investigated. A series of FAP tests were conducted on 33 cases of malignant gliomas in order to ascertain their efficacy in monitoring the progression of the disease in relation to imaging observations. To validate the presence of FAP expression in tumors, immunohistochemistry was conducted on four gliomas employing a FAP-specific antibody. Additionally, the investigation encompassed the correlation between postoperative tumor burden, as assessed through volumetric analysis, and the relative FAP level of serum autoantibodies. RESULTS: A considerable proportion of gliomas exhibited a significantly increased level of serum autoantibody relative FAP level. This elevation was closely associated with both histopathology and molecular pathology, and demonstrated longitudinal fluctuations and variations corresponding to the progression of the disease The correlation between the rise in serum autoantibody relative FAP level and tumor progression and/or exacerbation of symptoms was observed. CONCLUSIONS: The measurement of serum autoantibody relative FAP level can be used to detect the disease as a valuable biomarker. The combined utilization of its detection alongside MR imaging has the potential to facilitate a more accurate and prompt diagnosis.

[Clinical practice of whole-genome sequencing in the rapid diagnosis of critically ill neonates]. / é‡‡ç”¨å ¨åŸºå› ç»„æµ‹åºæŠ€æœ¯å¿«é€Ÿè¯Šæ–­å±é‡ç—‡æ–°ç”Ÿå„¿çš„ä¸´åºŠå®žè·µ.

OBJECTIVES: To explore the application of whole-genome sequencing (WGS) in the rapid clinical diagnosis of critically ill neonates. METHODS: The critically ill neonates who admitted to the neonatal intensive care unit of Children's Hospital of Fudan University and underwent WGS from August to September, 2019 were enrolled in this prospective study. The genetic testing results and clinical outcome were analyzed with reference to the sequencing data and clinical features of the neonates. RESULTS: A total of 15 neonates were tested, among whom there were 9 boys and 6 girls. The main reason for hospitalization included abnormal breathing in 7 neonates, poor response in 2 neonates, feeding difficulty in 2 neonates, fever in 1 neonate, hypothermia in 1 neonate, preterm birth in 1 neonate, and convulsion in 1 neonate. The mean turn-around time was 4.5 days for WGS. Finally a genetic diagnosis was obtained for 3 neonates, with a positive diagnostic rate of 20% (3/15). Among the 3 neonates, 2 neonates were withdrawn from the treatment due to severe conditions and 1 neonate died on the day when the sample was sent for genetic testing, whose etiology could be explained by the results of genetic testing. CONCLUSIONS: WGS technique can provide a timely and effective diagnosis for critically ill neonates suspected of genetic diseases and provide genetic evidence for clinical treatment of critically ill cases.

Evaluation of the community involvement of nursing experts in reducing unintentional injuries in children.

BACKGROUND: Nursing experts regularly visited the community to deliver safety education on the prevention of unintentional injuries in children to the parents of children aged 0-6 years and to pregnant women in a maternity school. This was undertaken to explore the effects of the measure on preventing unintentional injuries in children in Chizhou, China. METHODS: Using the convenience sampling method, the guardians(it means mother in this study)of children were investigated. The nursing experts visited communities in which the number of nursing experts is declining. Data on unintentional injuries in children in the previous year were collected retrospectively. RESULTS: After the nursing experts delivered safety education to the community, the scores of the questionnaire on unintentional injury prevention knowledge completed by children's guardians increased significantly (p < 0.01). Among the children whose guardians completed the questionnaire, there were 157 cases of unintentional injury in 2020 and 103 cases in 2021 (p < 0.05). The types of unintentional injuries included scratches, falls, sharp object injuries, swallowing of foreign bodies, burns and traffic accidents; there was no statistical difference (p > 0.05). However, there were significant differences in terms of gender ratio and location (p < 0.05). CONCLUSION: In conjunction with the maternity school for pregnant women and the vaccination programme, nursing experts delivered safety education regarding unintentional injuries in children; this may have promoted safety and protection awareness in the children's guardians and reduced unintentional injuries.

Potential protein-phenotype correlation in three lipopolysaccharide-responsive beige-like anchor protein-deficient patients.

BACKGROUND: Patients with lipopolysaccharide (LPS)-responsive beige-like anchor protein (LRBA) deficiency have a variety of clinical symptoms, but there is no apparent genotype-phenotype correlation, and patients carrying the same mutations may have different phenotypes. Therefore, it is not easy for doctors to make a decision regarding hematopoietic stem cell transplantation (HSCT) for LRBA-deficient patients. We hypothesized that there may be a protein-phenotype correlation to indicate HSCT for LRBA-deficient patients. AIM: To report on three Chinese LRBA-deficient patients and determine the correlation between residual protein expression and disease phenotypes. METHODS: Clinical data of three Chinese LRBA-deficient patients were collected, and protein levels were detected by Western blot analysis. In addition, LRBA mutation information of another 83 previously reported patients was summarized. RESULTS: All the major clinical findings indicated enteropathy, but patients 1 and 3 presented with more severe symptoms than patient 2. Endoscopy and histology indicated nonspecific colitis for patients 1 and 3 but Crohn's disease-like colitis for patient 2. Compound heterozygous mutations in LRBA were found in patient 1, and homozygous mutations in LRBA were found in patient 2 and patient 3. Only patient 2 responded well to traditional immunosuppressive treatment. Residual expression of the LRBA protein in patients 1 and 3 was very low, but in patient 2, a more than 0.5-fold in expression of the LRBA protein was found compared to that in the control. After HSCT, patient 1 had increased LRBA protein expression. We summarized the genetic information of 86 patients, and the mutations in patients 1 and 3 were novel mutations. CONCLUSION: We described three Chinese LRBA-deficient patients, two of whom carried novel mutations. These patients had no genotype-phenotype correlations, but their residual LRBA protein expression might be associated with disease outcome and could be an indicator for HSCT.

Cholestasis as a dominating symptom of patients with CYP27A1 mutations: An analysis of 17 Chinese infants.

BACKGROUND: CYP27A1 is the disease-causing gene of cerebrotendinous xanthomatosis (CTX). As a treatable lipid storage disease, early treatment can improve the prognosis. However, CTX patients reported in the literature are mostly adult patients; the phenotype spectrum of CTX in the infantile population remains elusive. OBJECTIVE: We aimed to investigate the phenotype spectrum of infants who carried pathogenic or likely pathogenic variants in the CYP27A1 gene and were suspected of having CTX. METHODS: From June 2014 to May 2020, infants with pathogenic or likely pathogenic variants in CYP27A1 gene were enrolled, who underwent next-generation sequencing or Sanger sequencing in Children's Hospital of Fudan University. Patient characteristics, clinical treatments and outcomes were extracted from electronic medical records. RESULTS: A total of 17 patients with an average onset age of 8 (1-42) days were found. The average diagnosis age was ten months. Cholestasis was the dominant symptom of these infants. Thirteen variants were detected, of which c.379C > T was a hotspot variant (26.5% alleles, 9/34). Cholestatic CTX is usually underestimated, but it could be severe or even fatal in infancy. For outcomes, 5 suffered from liver failure (36%, 5/14), 1 still showed cholestasis (7%, 1/14), 7 were asymptomatic (50%, 7/14), and 1 presented seizure and developmental delay in later childhood (7%, 1/14). CONCLUSION: Based on this infantile cohort, we concluded that it is necessary to consider the possibility of CTX caused by CYP27A1 gene variants for infants with cholestasis.

Ultra-low dose rituximab as add-on therapy in anti-MDA5-positive patients with polymyositis /dermatomyositis associated ILD.

OBJECTIVES: To evaluate the efficacy and safety of ultra-low dose (100 mg) rituximab (RTX) administration in anti-melanoma differentiation-associated gene 5 (MDA5) positive patients with polymyositis/dermatomyositis (PM/DM) associated interstitial lung disease. METHODS: This retrospective study included anti-MDA5 antibody positive ILD subjects in the First Affiliated Hospital of Guangzhou Medical University from November 2017 to March 2019. Independent predictors for 180-day mortality were measured by Cox regression analysis. Patients were divided into 3 groups: Group 1 (non-cyclophosphamide (CTX)/RTX) (n = 10), Group 2 (CTX only) (n = 19) and Group 3 (RTX with/without CTX) (n = 11). The 180-day mortality was compared among 3 groups with Kaplan-Meier analysis. Post-RTX serological parameters as well as adverse events were evaluated. RESULTS: Forty patients were included with the mean age of 51.3 years. Elevated IL-10 level and CD4+/8+ ratio were considered as risk factors of 180-day mortality. Kaplan-Meier analysis showed a trend toward decrease, albeit non-significant, in 180-day mortality in Group 3 (P = 0.26). The administration of 100 mg RTX brought down B cell within 7 days that lasted for 180 days. There were 7 and 6 infection events observed within 2 months of CTX/RTX treatment in Group 2 and 3, with 5 and 2 fatal cases respectively. Cytomegalovirus infection accounted for half infection events in Group 3. CONCLUSION: We found a pronounced and prolonged B cell depletion following 100 mg RTX infusion and RTX add-on may be effective in anti-MDA5 positive ILD patients. However, infection, especially opportunistic infection, should be concerned during the treatment.

[Analysis of the Temporal and Spatial Variation of PM2.5 in China Based on the LUR Model].

The land use regression (LUR) model is one of the most important systematic methods to simulate the temporal and spatial differentiation of the atmospheric pollutant concentration. To explore the adaptability of the LUR model to the simulation of air pollutants at the national scale in China and the temporal and spatial variation characteristics of fine air particulate matter (PM2.5) in China in 2015 and its correlation with different geographical elements, we built a LUR model. The LUR model is based on a geographically weighted algorithm using PM2.5 data acquired from the national control monitoring site in 2015 as the dependent variable and applying factors such as the type of land use, altitude, population, road traffic, and meteorological elements as independent variables. Based on model regression mapping, we obtained the distributions of monthly and annual PM2.5 concentrations nationwide in 2015 and analyzed the temporal and spatial variation characteristics of PM2.5 concentrations using the Hu line as a reference line. The results indicate that introducing the geographically weighted algorithm can significantly reduce the residual Moran's Ⅰ of the LUR model, weaken the spatial autocorrelation of residuals, and improve the coefficient of determination R2, which is better to reveal the complex relationship between the spatial distribution and impact factors of PM2.5. Cropland, forest, grass and urban industrial and residential land, and meteorological elements and major roads noticeably impact the PM2.5 concentration. Different spatial distributions of different geographical elements have distinct effects on PM2.5. The PM2.5 shows distinct temporal and spatial differences on both sides of the Hu line. The PM2.5 concentration is relatively high in developed cities with a large population and high industrialization levels. The concentration of PM2.5 is higher in winter and gradually decreases in autumn, spring, and summer.

Excessive bile acid activated NF-kappa B and promoted the development of alcoholic steatohepatitis in farnesoid X receptor deficient mice.

Chronic and excessive alcohol consumption can lead to alcoholic liver disease (ALD), which is characterized by a spectrum of liver disorders, including fatty liver, alcoholic steatohepatitis (ASH), fibrosis/cirrhosis and hepatocellular carcinoma (HCC). The mechanism of the progression from alcoholic steatosis to steatohepatitis and fibrosis is still not fully understood. As a nuclear receptor, farnesoid X receptor (FXR) plays a critical role in maintaining hepatic lipid and bile acid homeostasis. To clarify the role of FXR in the progression of steatohepatitis, we studied the effect of ethanol feeding on FXR-deficient mice. Wild-type and FXR-deficient mice were fed with Lieber-DeCarli ethanol liquid diet or an isocaloric control diet. We found that FXR-deficient mice fed with ethanol diet developed more severe liver injury and steatosis, even progressed to steatohepatitis and moderate fibrosis. Whereas, wild-type (WT) mice only developed mild level of steatosis, with rarely observed inflammatory foci and collagen accumulation. We also found that ethanol induced hepatic bile acid accumulation and NF-κB activation in FXR-deficient mice, which could be attenuated by ursodeoxycholic acid (UDCA). Thus, FXR deficient mice were more prone to develop alcoholic steatohepatitis and fibrosis upon ethanol diet feeding. Our results highlight the role of FXR in hepatoprotection during ALD development. Moreover, attenuating alcoholic liver cholestasis would be beneficial in preventing the progression of hepatic hepatitis in patients with ALD.

[The genetic features of drug resistance to group A streptococcus and macrolides antibiotics among pediatric patients in Beijing 2012].

OBJECTIVE: To investigate the genetic features of drug resistance to group A streptococcus(GAS) and macrolides antibiotics among pediatric patients in Beijing 2012. METHODS: A total of 199 strains of GAS were collected from 36 hospitals in Beijing between May and July, 2012. All strains were isolated from oropharyngeal swabs. The minimum inhibitory concentrations (MICs) of ten antibiotics (penicillin, ampicillin, erythromycin, clindamycin, tetracycline, levofloxacin, tigecycline, vancomycin, linezolid and streptogramin) were detected by VITEK-2 compact with GPS-67 test kit. The genes encoding macrolides resistance (ermA, ermB and mefA ) were amplified and tested by PCR. The macrolides resistant phenotype of group A streptococcus was detected by double disc test (D-test). RESULTS: Among 199 strains of GAS collected in this study, 101(50.8%) were from suburbs and the other 98(49.2%) were from urban areas. 111(55.8%) strains were collected from scarlet fever patients while the other 88(44.2%) were from oropharyngeal infection cases. All the strains were sensitive to penicillin and ampicillin, and the percentage of resistance to erythromycin, clindamycin and tetracycline were 96.5% (192/199), 95.5% (190/199) and 92.0% (183/199), respectively. All strains were susceptible to levofloxacin, tigecycline, vancomycin, linezolid and streptogramin. The rates of resistance to erythromycin, clindamycin and tetracycline were different in different districts, however, the difference in it between ages and clinical diagnosis did not show statistical significance (P > 0.05) . The detected rate of drug resistance gene ermB was 98.5% (196/199). The gene ermA was only detected out in 5 strains and the gene mefA was not detected out. 199 strains showed A macrolides resistant phenotype cMLS, while the phenotype iMLS was not found in this study. CONCLUSION: This study demonstrates the high level of clindamycin resistance in group A streptococcus collected from children in Beijing, 2012. The macrolides resistance of group A streptococcus was highly prevalent in Beijing, and the dominant phenotype was cMLS mediated by gene ermB.

[Application of EARS in early-warning of influenza pandemic in Beijing].

OBJECTIVE: To illustrate the efficiency of cumulative sum (CUSUM) in pre-warning of the influenza peak in Beijing. METHODS: CUSUM was used to analyze the data of influenza like illness (ILI), and the results of the influenza laboratory surveillance was regarded as the gold standard to judge the approaching of the influenza peak. RESULTS: The surveillance was launched in 421 hospitals in Beijing during the 2009 to 2010 influenza season, while the influenza laboratory surveillance was launched by 7 collaborative laboratories. From Jun. 2009 to Apr. 2010, the average ILI percentage in the 421 hospitals was 2.56%. In the study, 19 262 pharyngeal swab samples were collected from the ILI cases in 11 hospitals and 5 045 of them were tested positive for the influenza virus, with the novel swine-origin influenza A H1N1 virus dominating. After analyzing of the ILI surveillance data with CUSUM, it was found that the ILI surveillance in Beijing could make a satisfactory early warning for the approaching of the influenza peak referring to the gold standard based on the influenza laboratory results. CONCLUSION: It could give the prediction and early warning for the influenza peak efficiently and precisely, by using CUSUM to analyze the influenza surveillance data of Beijing.

[Characteristics and related factors related to the resistance on antibiotics among group A streptococcus strains isolated from children in Beijing, during May and July 2011].

OBJECTIVE: To analyze the characteristics of antibiotic resistance on group A streptococcus isolated from pediatrics in Beijing in 2011, to provide reference for clinical drug administration. METHODS: Strains of group A streptococcus were collected from the Departments of Pediatrics in 36 hospitals at different Districts of Beijing, from May to July 2011. Minimal inhibitory concentrations (MIC) with ten antibiotics of these isolates were tested by VITEK 2 Compact method. All the Susceptibility rate (S%), Intermediate rate (I%) and Resistance rate (R%) were calculated according to their MIC values. The macrolides resistant phenotype of group A streptococcus was detected by D-test. RESULTS: A total of 633 (19.1%) group A streptococcus strains were cultured from 3315 throat swabs. All the isolates were susceptible to penicillin, ampicillin, streptogramin, linezolid, tigecycline, vancomycin, while 96.5% (611/633) of the isolates were susceptible to levofloxacin. A total of the 96.1% (608/633) isolates exhibited resistance to erythromycin. The resistance rates to clindamycin and tetracycline were 79.3% (502/633) and 93.7% (593/633), respectively. A total of 9 different resistant patterns were observed, with the dominant patterns as:concomitant resistance to erythromycin, clindamycin and tetracycline (72.7%, 460/633), followed by combined resistance to erythromycin and tetracycline (18.0%, 114/633). The most commonly seen macrolide resistant phenotype was cMLS type (83.2%). In total, 97 strains belonged to iMLS type and 5 strains to M type. Data through multivariate logistic regression analysis showed that factors as occupation and samples being collected from the sub-urban areas etc. were significantly associated with the resistance rates to tetracycline and the odds ratio (95%CI) as 2.43 (1.16 - 5.09) and 2.35 (1.47 - 3.73). Isolates collected from the sub-urban areas were significantly associated with resistance rates to clindamycin, with the odds ratio (95%CI) being 0.48 (0.25 - 0.92). CONCLUSION: All the isolates acquired from the Pediatrics Departments in Beijing were susceptible to penicillin and ampicillin. The high resistance rates of erythromycin, clindamycin and tetracycline resistance to group A streptococcus were observed, with the major resistant phenotype as cMLS. Factors as occupation and the collection site of samples were significantly associated with the resistance rates to tetracycline while the sites of sample collection were significantly associated with the resistance rates to clindamycin.

[Study on types of M protein gene in group A streptococcus isolated from children in Beijing, 2011].

OBJECTIVE: To explore the distribution characteristics of the types of M protein gene (emm) in group A streptococcus (GAS) isolated from children in Beijing in the year 2011. METHODS: During May to July in 2011, a total of 3315 patients who were diagnosed scarlet fever or pharyngeal infection by doctors in pediatric outpatient and emergency units of 36 hospitals, were selected as subjects. Their throat swab samples were collected and isolated the strains of GAS. Gene emm was then amplified and sequenced by PCR method, and the differences in types of gene emm between different populations and diseases were compared. RESULTS: A total of 633 strains of GAS were isolated from the 3315 throat swab samples, 610 strains out of which were gene emm positive and were recruited in the study. Out of the 610 recruited strains, 448 (73.4%) were isolated from scarlet fever patients, the other 162 (26.6%) were isolated from pharyngeal infection patients; 397 (65.1%) were from urban, the other 213 (34.9%) were from suburb; 240 (39.4%) were from patients aging between 1 - 5 years old, the other 369(60.6%) were from patients aging 6 - 18 years old. A total of 8 types of gene emm (scarlet fever: 6 types, pharyngeal infection: 4 types) and 21 subtypes of gene emn (scarlet fever: 16 subtypes, pharyngeal infection: 10 subtypes) were identified. Three new subtypes were found in the study, naming emm1.63, emm12.62 and st5144.20. Among them, emm1.63 was found both in scarlet fever and pharyngeal infection patients, while emm12.62 and st5144. 20 were only found in pharyngeal infection patients. Among all the types of gene-emm, emm12 accounted for the highest percentage as 80.5% (491/610) and then followed by emm1 (18.0% (110/610)). Among all the subtypes, the dominant subtype was emm12.00, accounting for 69.0% (421/610), following by emm1.00 (16.9% (103/610)) and emm12.19 (6.1% (37/610)). All the above types and subtypes of gene emm were the most prevalent strains in scarlet fever patients and pharyngeal infection patients. Significant differences in the distribution of prevalent strains were observed among various aging patients and regions. The constituent ratios of emm1, emm1.00 and emm12.19 were higher in patients from suburb (emm1: 22.1% (47/213), emm1.00: 19.2% (40/213), emm12.19: 8.0% (17/213)) than those in urban areas (emm1: 15.9% (63/397), emm1.00: 15.6% (62/397), emm12.19: 5.0% (20/397)). The difference showed statistical significance (P < 0.05). The constituent ratio of emm1.00 was higher among patients aging 6-18 years old (19.2% (71/369)) than those aging 1 - 5 years old (13.3% (32/240)). The difference also showed statistical significance (χ(2) = 8.45, P < 0.05). CONCLUSION: Among the types of gene emm in GAS isolated from children in Beijing in year 2011, the most prevalent two were emm12 and emm1, and the most prevalent emm subtypes were emm12.00, emm1.00 and emm12.19. A significant difference in their distribution between various aging patients and isolated places can be obviously found.

[Quantitative evaluation on the effectiveness of prevention and control measures against pandemic influenza A (H1N1) in Beijing, 2009].

OBJECTIVE: To quantitatively evaluate the effectiveness of prevention and control measures against pandemic influenza A (H1N1) in Beijing, 2009 and to provide evidence for developing and adjusting strategies for prevention and control of the disease. METHODS: Considering the seasonality and the number of vaccination on pandemic influenza A (H1N1), data regarding pandemic influenza A (H1N1) in Beijing were collected and analyzed. Based on the dynamics of infectious disease transmission, a quantitative model for evaluation of prevention and control measures was developed. RESULTS: Both latency and infectious periods of pandemic influenza A (H1N1) were estimated to be 1.82 days and 2.08 days, respectively. The effective reproduction numbers of the three periods were 1.13, 1.65 and 0.96, respectively. Thanks to the implementation of a series of measures to prevent and control pandemic influenza A (H1N1), the cumulative number of laboratory-confirmed cases of pandemic influenza A (H1N1) was reduced, making it much smaller than what would have been under the natural situation. Specifically, the program on pandemic (H1N1) 2009 vaccination reduced the cumulative number of laboratory-confirmed cases by 24.08% and postponed the peak time. CONCLUSION: Measures that had been taken during this period, had greatly contributed to the successful prevention and control of pandemic influenza A (H1N1). The 2009 Pandemic (H1N1) vaccination was confirmed to have contributed to the decrease of cumulative number of laboratory-confirmed cases and postponed the peak arrival time.

[Investigation on the source of the first human of avian influenza A (H5N1) case in Beijing].

OBJECTIVE: To investigate the source of the first human case of avian influenza A (H5N1) infection in Beijing. METHODS: Interviewing the relatives of the case and other key persons, collecting and detecting samples of related biological, epidemiological and environmental data of the case were conducted. Later, the infection source was thoroughly investigated. RESULTS: The case ever contacted a slaughtered duck 5 days prior to the onset of illness, and the duck was bought from a stall of a wet market in Yanjiao area of Hebei province. Ten environmental samples were collected in this stall and the neighboring stall of the market. Another 6 samples were tested positive for H5N1 virus by PCR method, with 5 virus strains isolated. The whole-genome sequencing indicated that the amino acid homology between the H5N1 virus strains from the environment and the virus isolated from the case reached 99.8% - 100%. CONCLUSION: From both epidemiological and virological evidence, it was proved that the first human case of avian influenza A (H5N1) infection in Beijing was infected by a duck that carrying H5N1 virus the case contacted 5 days proceeding the onset of illness.