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.
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I- Evolution of the pandemic
In Canada, Mexico, and the United States, trends in acute respiratory disease continued to increase and the intensity of such diseases remained high this week. Canada has experienced increased national rate of ILI consultation, above what is expected for this time of year since EW 37.
The geographic spread of influenza continued to be widespread. Based on information available from Mexico’s web page 1, as of the 13th of October, the greatest numbers of cumulative laboratory-confirmed cases were seen in the Federal District, Chiapas, Yucatan, Nuevo Leon, Jalisco, San Luis Potosi, and Tamaulipas. When comparing against cases reported in the previous week (8 October), the greatest increases were observed in Nayarit, Durango, Nuevo Leon, Sonora, Morelos, and Guerrero.
Few Caribbean countries reported qualitative indicators for this week, but those who did reported increasing or unchanged trends in acute respiratory disease. Reporting CAREC countries2, maintain a low level of respiratory disease activity, but there have been reports of outbreaks in school settings.
Cuba continued to report high intensity of acute respiratory disease. Overall, impact on health care services due to acute respiratory disease was moderate.
Most countries providing an update this week report widespread geographic spread of influenza except for El Salvador which continues to report regional spread. Trends of acute respiratory disease were reported as decreasing or unchanged, with the exception of El Salvador, which reported a new increasing trend. The intensity of acute respiratory disease was mostly low/moderate, again with the exception of El Salvador, which again reported high intensity. Impact on heath care services due to acute respiratory disease was low or moderate.
This sub-region still notes moderate pandemic influenza activity compared to southern temperate regions, albeit in decreasing trends. Colombia was the only country to report an increasing trend of acute respiratory disease. The impact on heath services of acute respiratory disease was low or moderate.
The Southern Cone of South America is experiencing a decrease in intensity of respiratory disease, except in Paraguay, who newly reported a high intensity. For the remaining countries in this sub-region the situation reported remains largely unchanged since last EW
• The intensity of acute respiratory diseases in North America was high in Canada, Mexico, and the U.S.
• In Central America had a low or moderate intensity of acute respiratory disease; with the exception of El Salvador, which had a high intensity of acute respiratory disease and an increasing trend of acute respiratory disease
• Caribbean countries reported increasing or unchanged trends in acute respiratory disease, with outbreaks in schools.
• Most of South America had a decreasing trend and low or moderate intensity of acute respiratory disease; Colombia, however, had an increasing trend in acute respiratory disease
• 81.95% of subtyped influenza A viruses were pandemic (H1N1) 2009
• 133 new confirmed deaths in 10 countries (3539 cumulative deaths)
II-Descriptions of hospitalizations and deaths among confirmed cases of pandemic (H1N1) 2009
A table containing case counts reported to PAHO is included in Annex 2.
Among hospitalized confirmed cases (Table 1), approximately half were women. While the greatest number of cases was among young adults, the highest rates of hospitalization were o bserved in children.
Pregnant women also had a higher burden of morbidity and mortality. In Canada, while 1% of the population is pregnant in a given year, approximately 5% of hospitalized cases and 5% of the deaths were in this group.
Caribbean Epidemiology Center (CAREC) reports that 30% of the hospitalized cases presented with gastrointestinal symptoms, which is higher than what was seen in non-hospitalized cases (20%).
In assessing the deaths among confirmed cases, women represent 49-60 %(Table 2). The deaths have taken place mostly among adults. More than two thirds of deceased cases had underlying comorbidities, and the percentage of pregnant women ranges from 20-27%.
III- Viral Circulation
For the purpose of this analysis, only countries which reported data on influenza A subtypes were considered.
We excluded from the calculations of the percentages, results from samples of influenza A that were not subtyped or were unsubtypeable. Until EW 39, pandemic (H1N1) 2009 appears to continue to be the influenza virus in circulation.
IV Antiviral Resistance
The Centers for Disease Control and Prevention (CDC) complete antiviral susceptibility testing on isolates submitted by various countries in the Region. To date, all 163 samples submitted from 18 countries were found to be sensitive to neuraminidase inhibitors (oseltamivir and zanamivir) but resistant to adamantanes.
As of EW 40, the United States and Canada each reported a new case oseltamivir-resistant pandemic (H1N1) 2009, bringing their total to 13 and 3 cases, respectively.
As of 16 October, a total of 160,129 confirmed cases have been notified in all 35 countries in the Americas Region. A total of 3,539 deaths have been reported among the confirmed cases in 26 countries of the Region. Trinidad and Tobago reported its first deaths during this epidemiological week.
In addition to the figures displayed in Annex 1, The following overseas territories have confirmed cases of pandemic (H1N1) 2009: American Samoa, U.S. Territory (8); Guam, U.S. Territory (1); Puerto Rico, U.S. Territory (20); Virgin Islands. U.S. Territory (49); Bermuda, UK Overseas Territory (1); Cayman Islands, UK Overseas Territory (103, 1 death); British Virgin Islands, UK Overseas Territory (12); Turks and Caicos Islands (36); Martinique, French Overseas Community (44, 1 death); Guadeloupe, French Overseas Community (27); Guyane, French Overseas Community (29, 1 death);Saint-Martin, French Overseas Community (19); Saint Bartholomew, French Overseas Community (2); Netherlands Antilles, Aruba (13); Netherlands Antilles, Bonaire (31); Netherlands Antilles, Curaçao (50)*; Netherlands Antilles, St. Eustatius (1); and Netherlands Antilles, St. Maarten (24).
* Three cases were reported on a cruise-ship.The distribution of cases and deaths at the first sub-national level can be found in the interactive map available through the following link: http://www.paho.org/hq/images/atlas/en/atlas.html
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