Objective To develop and verify an influenza A virus antigen-detecting kit which can detect all the subtypes of influenza A virus. Methods Double-antibodies sandwich enzyme linked immunosorbent assay (ELISA) was utilized for developing the influenza A virus antigen-detecting kit. The sensitivity, specificity, accuracy and stability of the kit were evaluated by the clinical samples. Results The lower detection limit of the kit for the N protein was 7. 63 ng/mL, which was 256 times lower than that of the hemagglutination and 16 times lower than that of immune colloidal gold technique. The kit didn't show any cross-reaction with the influenza B virus, respiratory syncytial virus, respiratory adenovirus, para-influenza virus type Ⅰ and Ⅲ, mycoplasma pneumomiae, avian newcastle disease virus, avian infectious bursal disease virus or avian infectious bronchitis virus. The specificity was 100%. Both the intra batch variaton coefficient (CV) value and inter batch CV value were less than 15%, which met the national standard for ELISA kits. The results proved that the kit could keep stable at 4 ℃ for more than 1 year and at 37 ℃ for more than 7 days. The kit could identify H1N1, H3N2, H5N1 and H9N2 influenza A viruses. The clinical research data of human influenza virus showed the consistency rate between the kit and regular cell culture method was 93. 44% for the positive samples and 99. 31% for the negative samples. The clinical research data of avian influenzavirus showed the consistency rate between the kit and regular cell culture method was 95. 45% for positive samples and 98. 09% for negative samples. Conclusion The influenza A virus antigen-detecting ELISA kit can be used for the epidemiological survey of the infection of human influenza A virus or avian influenza virus with high sensitivity and specificity.

Objective To investigate the epidemiological characteristic of influenza in children in Guangzhou ,and provide the sci-entific basis for prevention .Methods A total of 20 throat swabs were collected from children with influenza-like illness(ILI) each week from 2014 to 2015 .A total of 2080 samples were obtained .The virus was isolated with MDCK cell line and virus type identi-fication were detected by real-time PCR .The relevant data was collected and analyzed epidemiologically .Results A total of 244 were detected positive in 2080 ILI cases in Guangzhou from 2014 to 2015 .The positive rate was 11 .7% .The positive rate of influ-enza virus reached peak in February and June in 2014 ,and the major type of influenza virus was new type H1N1 in February and H3N2 in June .The positive rate of influenza virus reached peak in March and June in 2015 ,and the major type of influenza virus were B type in March and H3N2 in June .Only one case of new H1N1 was detected in 2015 .The positive rate of influenza virus was 25 .6% in 3 to 6 years old ILI children which took larger part than other groups .Conclusion In Guangzhou ,the influenza virus epi-demic is more active in 2015 .The major type of influenza virus in the epidemic is seasonal type H 3N2 and B .Type A and type B appeared in the epidemic alternatively .The 3-6 year-old children are the high-risk group of influenza infection ,and should be monitored .

ObjectiveTo conduct a molecular epidemiological study on human metapneumovirus (hMPV) among pediatric patients in Guangzhou. MethodsA total of 1 840 clinical specimens were obtained from pediatric patients with respiratory infections in Guangzhou Women and Children' s Medical Center in 2010.hMPV was detected by real-time TaqMan RT-PCR in clinical specimens.F gene was amplified and the PCR-products were directly sequenced. ResultsIn 1 840 clinical specimens, 66 werehMPV-positive with a positive rate of 3.59％. hMPV was detected in all specimens except those collected in September and October, and the highest positive hMPV rate occurred in April (6.09％). The F genes of 3 randomly selected strains and hMPVgz01 ( isolated in 2008) were compared with subgroups A1, A2, B1,B2 and C, and the highest homology was with BJ1887 strain of genotype A2b (97％). The F genes of the randomly selected strains and hMPVgz01 were 99％ identical to each other. Sequences and phylogenetics analysis revealed that the epidemical strain in Guangzhou belonged to genotype A2b. ConclusionhMPV is prevalent in spring and summer among children in Guangzhou, and A2b is the predominant genotype.

Objective To study the epidemiology of hand,foot,and mouth disease (HFMD) and the spectrum of serotypes in the other enterovirus (EV) (non-EV-A71 and non-Coxsaekievirus group A 16,CV-A 16) from 2016 to 2017 in Guangzhou,to provide the basis for its treatment,prevention and control.Methods Enteroviruses universal type,EV-A71 and CV-A16 were detected by real time reverse transeription-polymerase chain reaction in the specimens from HFMD suspected patients from 2016 to 2017.The positive specimens of non-EV-A71 and non-CV-A16 were amplified and sequenced based on 5'-untranslated region (UTR) region.The spectrum of serotypes was analyzed with BLAST in NCBI on the basis of 5'-UTR region.Results A total of 25779 specimens from HFMD patients were collected during 2016-2017,16 300 (63.23 ％) of which were positive.The positive rates of EV-A71,CV-A16,non-EV-A71 and non-CV-A16 were 4.57％ (1 178/25 779),12.70％ (3 274/25 779) and 45.96％ (11 848/25779),respectively.The average positive rate of non-EV-A71 and non-CV-A16 in 2017 was 55.68％,which was higher than that in 2016.Sequence analysis showed that there were 16 genotypes in 95 non-EV-A71 and non-CV-A16 positive specimen,including CV-A6,CV-A10,CV-A4,CV-A2,CV-A8,CV-A12,CV-A9,Coxsakievirus B5 (CV-B5),CV-B2,CV-B4,CV-B3,Echovirus 1 (E1),E16,E30,E2 and E18.CV-A6 (26.32％),and CV-A10 (15.79％) were the most common genotypes,followed by CV-A4 (6.32％)、CV-A8(4.21％),and CV-A2 (4.21％).Conclusions The infection rate of EV-A71 is very low during 2016-2017.From April to July 2016,there is a small peak of CV-A16 infection.The non-EV-A71 and non-CV-A16 enterovirus becomes the main causative agent of HFMD during 2016 to 2017.CV-A6 and CV-A10 are the most prevalent pathogens of non-EV-A71 and non-CV-A16 enterovirus.Research and monitoring of CV-A6,CV-A10 as the main non-EV-A71and non-CV-A16 virus should be strengthened.