National Institute for Viral Disease Control and Prevention, China CDC Chinese Weekly Report (All data are preliminary and may change as more reports are received) Summary During week 17, influenza activity in both southern and northern provinces was at inter-seasonal levels, only a few influenza viruses can be detected, the majority were A(H1N1)pdm09. Among influenza viruses antigenically characterized by CNIC since October 1st, 2017, 239(91.9%) influenza A(H1N1)pdm09 viruses were characterized as A/Michigan/45/2015-like; 116(32.3%) influenza A(H3N2) viruses were characterized as A/Hong Kong/4801/2014 (H3N2)(EGG)-like, 324(90.3%) influenza A(H3N2) viruses were characterized as A/Hong Kong/4801/2014 (H3N2)(CELL)-like; 106(53.8%) influenza B/Victoria viruses were characterized as B/Brisbane/60/2008-like; 527(97.2%) influenza B/Yamagata viruses were characterized as B/Phuket/3073/2013-like. Among the influenza viruses tested by CNIC for antiviral resistance analysis since October 1st, 2017, all influenza A(H1N1)pdm09 and A(H3N2) viruses were resistant to adamantine; All influenza A(H1N1)pdm09, A(H3N2) and B viruses were sensitive to neuraminidase inhibitors. 1
Outbreak Surveillance During week 17(Apr 23 rd Apr 29 th, 2018), there were 2 outbreaks reported nationwide, 1 of them was A(H1N1)pdm09, 1 of them was not obtained testing result. Surveillance of outpatient or emergency visitss for -like Illness (ILI) During week 17, the percentage of outpatient or emergency visits for ILI (ILI %) at national sentinel hospitals in south China was 3.6%, same as the last week (3.6%), higher than the same week of 2015-2017(2.9%, 3.5%, 3.1% ). (Figure 1) Figure 1. Percentage of Visits for ILI at Sentinel Hospitals in South China (2015-2019) During week 17, ILI% at national sentinel hospitals in north China was 2.3%, lower than last week and the same week of 2015-2017(2 2.4%, 2.4% %, 2.5%, 2.5%). (Figure 2) 2
Figure 2. Percentagee of Visits for ILI at Sentinel Hospitals in North China (2015-2019) Virologic Surveillance During week 17, influenza network laboratories tested 5036 specimens, of which 145(2.9%) were positive for influenza, influenza A and influenza B viruses were 107(73.8%) and 38(26.2% %), respectively (Table 1). During week 17, the percentage of specimens that were tested positive for influenza in south China was 3..1%, which was lower than the previous week (4.1%) (Figure 3). During week 17, the percentage of specimens that were tested positive for influenza in north China was 2..2%, which was similar to the previous week (3.7%). (Figure 4). Table 1 Laboratory Detections of ILI Specimens (Week 17, 2018) Week 17 South China North China Total No. of specimens tested 3847 1189 5036 No. of positive specimens (%) 119(3.1%) 26(2.2%) 145(2.9% %) A 93(78.2%) 14(53.8%) 107(73.8% %) A(H3N2) 4(4.3%) 1(7..1%) 5(4.7%) 3
A(H1N1) )pdm09 89(95.7%) 13(92.9%) 102(95.3% %) A (subtype not determined) 0( (0) B 26(21.8%) 12(46.2%) 38(26.2% %) B (lineage not determined) 0( (0) Victoria 2(7.7%) 4(33.3%) 6(15.8% ) Yamagata 24(92.3%) 8(66.7%) 32(84.2% %) Figure 3. Positive Testss Reported by Southern Network Laboratories (Week 14, 2017 ) Note: Analysis in this part was based on the test results of network laboratories. If it weree not consistent with the results of CNIC confirmation, the results of CNIC confirmation were used. 4
Figure 4. Positive Testss Reported by Northern Network Laboratories (Week 14, 2017 ) Note: Analysis in this part was based on the result of network laboratories. If it were not consistent with the results of CNIC confirmation, the results of CNICC confirmation were used. Antigenic Characterization Since October 1 st, 2017, 239(91.9%) influenza A(H1N1)pdm09 viruses were characterized as A/Michigan/45/2015-like; 116(32.6%) influenza A( (H3N2) viruses were characterized as A/Hong Kong/4801/2014 (H3N2)(EGG)-like, 324(90..3%) influenza A(H3N2) viruses weree characterized as A/Hong Kong/4801/2014 (H3N2)(CELL)-like; 106( (53.8%) influenza B/Victoria viruses were characterized as B/Brisbane/60/ /2008-like; 527(97.2%) influenza B/Yamagata viruses were characterized as B/Phuket/ /3073/2013-like. Antiviral Resistance Since October 1 st, 2017, among the influenza viruses ested by CNIC for antiviral resistance, all influenza A( (H1N1)pdm09 and A(H3N2) viruses were resistant to adamantine; All influenza A(H1N1)pdm09, A(H3N2) and B viruses were sensitivee to neuraminidase inhibitors. H7N9 case report Since the notification of human infection with novel reassortant influenza 5
National Institute for Viral Disease Control and Prevention, China CDC A(H7N9) virus on 31 March 2013, in total 1564 laboratory-confirmed cases have been reported to WHO. Among them, 32 cases were infected with HPAI A(H7N9) virus, which have mutations in the hemagglutinin gene indicating a change to high pathogenicity in poultry. These 32 cases are from Taiwan (the case had travel history to Guangdong), Guangxi, Guangdong, Hunan, Shaanxi, Hebei, Henan, Fujian, Yunnan provinces, with illness onset date before October 2017. No increased transmissibility or virulence to human case was detected in the HPAI A(H7N9) virus. 6