SUMMARY Influenza Situation Update 10 June 2014 http://www.wpro.who.int/emerging_diseases/influenza/en/index.html Northern Hemisphere In the Northern Hemisphere countries, influenza-like illness (ILI) activity was variable. In northern China, the percentage of visits for ILI (ILI%) at national sentinel hospitals established in 2009 in north China was 2.7% in week 22 (26 May to 1 June 2014), slightly higher than the previous week (2.6%) and the same as the same week in 2013. In contrast, the proportion of ILI specimens positive for influenza declined substantially: 4 of 573(0.7%) ILI specimens were positive for influenza. Of the positive specimens, 2 were influenza A (H3N2) and 2 were influenza B. In Mongolia, during the week 22(26 May to 1 June 2014), ILI activity based on the proportion of outpatients exhibiting ILI continued to show an overall decreasing trend. Whilst the proportion of patients with pneumonia among the hospitalized has continued to increase in the past month, exceeding the tolerance limit. Proportion of ILI specimens decreased to 4% with only 1 of 23 specimens positive for influenza (influenza A(H1)). In Japan, during week 21 (19 to 25 May 2014), ILI activity decreased; the number of ILI cases per sentinel reporting site was 0.56, substantially lower than the figure from the previous report. Similarly, in the Republic of Korea, for the week ending 31 May 2014, ILI activity slightly increased with the overall proportion of ILI cases per 1000 patients being 4.1, below the national baseline of 12%. Proportion of ILI specimens positive for influenza also decreased; there were no specimens positive for influenza virus of the 22 specimens submitted for influenza testing, during 18 to 24 May 2014. Subtropics/Tropics In the subtropics/tropics, overall ILI activity remained variable. In Southern China, the ILI at national sentinel hospitals in south China, established in 2009, was 3.6% in week 22 (26 May to 1 June 2014), which was higher than the previous week (3.2%) and higher than the same week in 2013. The proportion of ILI specimens positive for influenza also increased to 6.0 % (174 of 2907 specimens). Of the positive specimens, 134 (77%) were influenza A (124 were H3N2, 1 was subtype undetermined and 9 were (H1N1)pdm09) and 40 (23%) were Influenza B. In Hong Kong (China), during 25 to 31 May 2014, overall influenza activity is low. Of the 126 (6.1%) samples positive for influenza during this week, 6 were influenza A(H1N1)pdm09, 66 were influenza A(H3), 45 were influenza B viruses, and 9 were influenza C viruses. Hospital admission rates with principal diagnosis of influenza for children aged 0 4 years, persons aged 5 64 years and persons aged 65 years and above were 0.58, 0.05 and 0.16 cases per 10 000 people, respectively. Additionally, weekly number of deaths with any diagnosis of influenza in public hospitals has increased. In the Mekong, influenza activity was variable. In Lao PDR, influenza activity increased slightly. During 18 to 24 May 2014, 7 of 47 (15%) ILI specimens was positive for influenza: 2 were influenza A(H1N1)pdm091, 4 were influenza A(H3) and 1 was influenza B. In Viet Nam, influenza activity decreased. During 11 to 17 May 2014, 2 of 6 ILI specimens were positive for influenza B (lineage not determined). 1
In Singapore, acute respiratory infection (ARI*) activity during 25 to 31 May 2014 was slightly lower than the previous week: 2649 patients sought treatment compared to 2754 patients the previous week. The proportion of cases with ILI among the polyclinic ARI cases remained low at 1%. Of 197 ILI samples collected in the past 4 weeks in the community, 51.3% were positive for influenza virus. Of all the influenza virus isolates in May 2014, 18% were influenza A(H1N1)pdm09, 21% were influenza A(H3N2), and 62% were influenza B. Southern Hemisphere In the Southern Hemisphere, overall ILI activity is low, despite the beginning of the flu season. In Australia, ILI activity remained at low level. During the week 18 to 24 May 2014, 14 of 291 (4.8 %) ILI specimens tested positive for influenza: 7 were influenza A(H1N1)pdm09,, 6 were influenza A(H3) and 1 was influenza B (lineage not determined). In New Zealand, during 26 May to 1 June 2014, influenza activity remained below the baseline threshold. 22 out of 196 samples received were positive for influenza: 9 were influenza A(H1N1)pdm09, 2 were influenza A(H3) and 11were influenza A (not subtyped). Pacific Islands In the Pacific Islands, ILI activity was variable with a decreasing trend observed in a number of islands. During the week ending 1 June 2014, none of the islands reported weekly ILI case numbers above the threshold of 90% of their historical values. Global influenza situation Epidemiological update: http://www.who.int/influenza/surveillance_monitoring/updates/latest_update_gip_surveillanc e/ Virological update: http://www.who.int/influenza/gisrs_laboratory/updates/summaryreport *ARI defined as clinical diagnosis of acute upper respiratory tract infection (ICD9 460 465: Acute Nasopharyngitis (common cold); 461 Acute Sinusitis; 462 Acute Pharyngitis; 463 Acute Tonsillitis; 464 Acute Laryngitis and Tracheitis; 465 Acute Upper Respiratory Infections of Multiple or Unspecified Sites; 466 Acute Bronchitis and Bronchiolitis). ILI defined as temperature >38C with cough or sore throat. 2
Percentage of visits that were ILI in sentinel hospitals in north China up to 1 June 2014, 2010 2014 (Source: Chinese National Influenza Center) Percentage of Visits that were ILI in sentinel hospitals in south China, up to 1 June, 2010 2014 (Source: Chinese National Influenza Center) 3
Proportion of outpatients that were ILI (per 10000) Mongolia up to 1 June 2014 (Source: National Influenza Center of Mongolia) Proportion of patients with pneumonia among hospitalized Mongolia, up to 1 June2014 (Source: National Influenza Center of Mongolia) 4
Influenza cases reported per sentinel weekly Japan up to 25 May in 2014 (Source: National Institute of Infectious Diseases) The weekly proportion of ILI visits per 1,000 patients Republic of Korea up to 31 May in 2014 (Source: Korean Center for Disease Control and Prevention) 5
consultation rates at sentinel general outpatient clinics, Hong Kong (China) up to 31 May 2014 (Source: Centre for Health Protection) ILI ILI consultation rates at sentinel private doctors Hong Kong (China) up to 31 May 2014 (Source: Centre for Health Protection) 6
Influenza associated hospital admission rates and deaths Hong Kong (China) up to 31 May 2014 (Source: Centre for Health Protection) Singapore up to 31 May in 2014 (Source: Ministry of Health) 7
New Zealand up to 1 June in 2014 (Source: Ministry of Health and Institute of Environmental Science & Research Ltd.) Note: Numbers of reported cases are not comparable between countries. The purpose of the charts is to show trends over time within each country/area. Pacific Islands up to 1 June 2014 (Source: Pacific Public Health Surveillance Network) 8