-In North America, acute respiratory disease activity continued to decrease and is lower than expected in some areas
- In the Caribbean, all countries reported unchanged and decreasing trends in acute respiratory disease
- Central America reported decreasing or unchanged trends in acute respiratory disease
- South American countries reported mostly decreasing trends of acute respiratory disease
- A median of 99.6% of subtyped influenza A viruses in North America were pandemic (H1N1) 2009
- Since December 18th: 203 new confirmed deaths in 8 countries were reported; in total there have been 6,880 cumulative confirmed deaths
The information contained within this update is obtained from data provided by Ministries of Health of Member States and National Influenza Centers through reports sent to Pan American Health Organization (PAHO) or updates on their web pages.
I- Evolution of the pandemic
In Canada, in EW 50, the national influenza-like illness (ILI) consultation rate remained below the historical average for the second consecutive week. The overall number of hospitalizations, ICU admissions, and deaths associated with the pandemic virus decreased approximately 50% as compared to the prior week (EW 49). A total of nine oseltamivir-resistant isolates have been detected since April 2009.
In Mexico, from EW 49 to EW 50, there was a 53% decrease in the number ILI and severe acute respiratory illness (SARI) cases, and the activity has now been decreasing for eight consecutive weeks. The intensity of acute respiratory disease, however, was high.
In the United States, the proportion of outpatient consultations for ILI decreased in EW 50 but increased in EW 51, remaining above the national baseline. In EW 50, three of ten and in EW 51, five of ten, sub-national surveillance regions reported the proportion of outpatient visits for ILI to be above their region-specific baseline. Laboratory-confirmed influenza hospitalization rates remained stable but high, especially in children 0-4 years of age. The proportion of deaths attributed to pneumonia and influenza dropped below (EW 50) but then increased above (EW 51) the epidemic threshold. A total of nine influenza-associated pediatric deaths were reported in EW 50 and four in EW 51; 10 of these were associated with the pandemic virus. A total of 50 oseltamivir-resistant isolates have been detected since April 2009.
In EW 50 and 51, these countries reported decreasing or unchanged trends in acute respiratory disease, low/moderate intensity of acute respiratory disease and low or moderate impact of acute respiratory disease on health care services.
In countries providing these data1, for the three consecutive weeks (EW 47-49), SARI hospitalization incidence decreased.
In EW 50 and 51, these countries reported decreasing or unchanged trends in acute respiratory disease, low/moderate intensity of acute respiratory disease and low impact of acute respiratory disease on health care services.
Guatemala (EW 50) reported a decrease of 15% and 17.6% of acute respiratory disease cases and pneumonia cases, respectively, as compared to the prior week.
Most of these countries reported widespread influenza activity in EW 50 and 51. Acute respiratory disease trends were reported as decreasing, except in Peru, which reported an increasing trend in EW 50, but a decreasing trend in EW 51. The intensity of acute respiratory disease and the impact of acute respiratory disease on health-care services were reported as low or moderate for these countries.
In Peru, nationally, the peak of SARI was in EW 28, and since EW 34 there has been a consistently decreasing trend.
Influenza activity was reported as widespread in Argentina (EW 48) and regional in Brazil (EW 50, 51). These countries reported continued decreasing trends of acute respiratory disease, low/moderate intensity of acute respiratory disease, and low or moderate impact of acute respiratory disease on health-care services.
In EW 48, Argentina reported decreasing ILI activity in 15 of 20 regions (information was not available for three regions). The incidence of ILI continued to be low (7 per 100,000 habitants) and has been below the epidemic threshold since EW 40.