The information presented in this update is based on data provided by Ministries of Health and National Influenza Centers of Member States to the Pan American Health Organization (PAHO) or from updates on the Member States’ Ministry of Health web pages.
Regional Update EW 48, 2014
- North America: Influenza activity continued to increase but remained low. In Canada, ILI activity has remained above expected levels since epidemiological week (EW) 35. Influenza detections (15.2% of positivity) continued to increase with an upward trend since EW 37. Influenza A(H3N2) and influenza A (not subtyped) have predominated among circulating influenza viruses; 10 influenza A(H3N2) viruses have been characterized of which two (20%) were A/Texas/50/2012, component of the 2014-2015 northern hemisphere vaccine and eight showed reduced titers. The detections of RSV have continued to increase since EW 40. Influenza hospitalizations have continued to increase since EW 46. In the United States, ILI activity continued to increase and this week was above the national baseline (2.6%). During EW 48, widespread influenza activity was reported by six states (Alaska, Florida, Illinois, Louisiana, Maryland, and North Carolina). Influenza detections continued to increase (17% of positivity) and influenza A (not subtyped) and influenza A(H3) have predominated among the circulating influenza viruses; 114 influenza A(H3N2) viruses have been characterized of which 48 (42%) were A/Texas/50/2012-like, the component of the 2014-2015 northern hemisphere vaccine and 66 (58%) showed reduced titers. Most viruses that showed reduced titers were antigenically similar to A/Switzerland/9715293/2013, the influenza A(H3N2) virus selected for the 2015 southern hemisphere vaccine. RSV detections have continued to increase since EW 39. The overall hospitalization rate was 1.8 per 100,000 population with the highest rate among adults aged ≥65 years (5.9 per 100,000). From mid-August to 4 December, 1,121 cases of Enterovirus D68 have been recorded in 47 states and the District of Columbia and reports from most states over the last months have indicated reduced Enterovirus D68-like illness activity. In Mexico, ARI activity remained within the endemic channel and the proportions of SARI/ILI consultations remained below 2%. The proportion of positive samples for influenza was 20.2% with a predominance of influenza A(H3N2).
- Caribbean: Respiratory virus activity remained low with the exception of Cuba. In Cuba, influenza A(H3N2) detections increased in the last weeks. In Puerto Rico, ILI activity (as reported to CDC) was reported high; however, influenza detections remained low and decreased during the last eight weeks. In Saint Lucia, the number of cases of fever and acute respiratory symptoms continued to decrease this week since it peaked in EW 44. Among respiratory viruses, circulation of RSV and influenza A(H3N2) (Cuba) and influenza B (Jamaica) were observed.
- Central America: Respiratory virus activity remained low with the exception of Costa Rica and Guatemala. In Costa Rica, SARI activity continued to increase since EW 36, associated to increased circulation of influenza A(H3N2) and RSV. In Guatemala, respiratory virus detections (mainly RSV) have been increasing during the last four weeks. Among respiratory viruses, circulation of RSV is decreasing, but still remaining in Costa Rica, Guatemala and Nicaragua and influenza A(H3N2) were detected in Costa Rica, Honduras and Panama.
- Andean Sub-region: Respiratory virus activity remained low and ARI/SARI activity are within expected levels (Colombia, Ecuador). Among respiratory viruses, circulation of RSV (Colombia, Ecuador), influenza A(H3N2) (Ecuador) and parainfluenza (Colombia, Peru) were observed.
- Southern Cone: Respiratory virus activity and ARI/SARI activity have continued to decrease and are within expected levels. There have been very few influenza and other respiratory virus detections in the last weeks (Argentina, Brazil, Chile, Paraguay, Uruguay).