Thursday, November 19, 2009

INFLUENZA PANDEMIC (H1N1) 2009 (108): PAHO UPDATE

A ProMED-mail post

ProMED-mail is a program of the
International Society for Infectious Diseases


Date: Mon 16 Nov 2009
Source: Pan American Health Organization (PAHO), Epidemiological
Alerts [edited]



Regional update: pandemic (H1N1) 2009
-------------------------------------
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 the Pan American Health
Organization (PAHO) or updates on their web pages.


Evolution of the pandemic
-------------------------
North America
-------------
In Canada, the national influenza-like illness (ILI) consultation
rate slightly decreased compared to last week but remained above
average for the 6th consecutive week. The number of influenza
outbreaks remained high and these outbreaks were mostly reported in
the school setting. The proportion of tests positive for influenza
again increased this week to 38.1 percent from 36.3 percent (EW 43).
The total number of hospitalizations of persons with pandemic
influenza increased again this week; and hospitalization rates were
highest among those less than 20 years of age.

In Mexico, trends of acute respiratory disease remained unchanged,
with high intensity of acute respiratory disease, and moderate impact
of acute respiratory disease on health care services. Of note is that
the number of ILI [influenza-like illnesses] and severe acute
respiratory illness (SARI) cases, in EW 39 [27 Oct-3 Nov 2009],
surpassed what was observed in the 1st wave of the pandemic.

In the United States, the proportion of outpatient consultations for
ILI decreased for the 2nd consecutive week. Laboratory-confirmed
influenza hospitalization rates remained high, especially in children
0 to 17 years of age. The proportion of deaths attributed to
pneumonia and influenza remained above the epidemic threshold for the
6th consecutive week. 9 of 10 sub-national surveillance regions
reported decreases in proportion of outpatient visits for ILI as
compared to the previous week, but all 10 reported a the ILI
proportion to be above their region-specific baseline. A total of 35
influenza-associated pediatric deaths were reported this week, of
which 26 were associated with the pandemic virus. In total, since 30
Aug 2009, 98 pediatric deaths associated with the pandemic virus have occurred.

Caribbean
---------
These countries are reporting mostly unchanged trends in acute
respiratory disease and high intensity of acute respiratory disease.
Impact of acute respiratory disease on health care services was
reported as moderate. In countries providing these data, severe acute
respiratory infection (SARI) hospitalization rates decreased this
week, after 4 consecutive weeks of increases.

Central America
---------------
This week, among the countries that provided information, trends of
acute respiratory disease decreased. Intensity of acute respiratory
disease remained low/moderate and impact of acute respiratory disease
on health care services was low.

South America
-------------
Andean:
These countries continued to report widespread influenza activity.
Acute respiratory disease trends were reported as decreasing or
unchanged in most countries of the region, except Colombia and Peru,
which reported an increasing trend in acute respiratory disease. In
Peru, in the last week, the greatest increase in the number of
confirmed cases was observed in parts of the northeast jungle region.
In Ecuador, nationally, trends of acute respiratory disease were
reported as unchanged, but 3 of 24 provinces reported increases in
the number of SARI cases as compared to the prior week.

Venezuela's Ministry of Health reported that the outbreak of acute
respiratory infection in indigenous Yanomami communities has ended.
[For details, see ProMED-mail Influenza pandemic (H1N1) 2009 (90):
Venezuela, Yanomami 20091105.3820].

Southern cone:
Most of these countries reported decreasing or unchanged trends of
acute respiratory disease. This week, Paraguay reported 2 of 17
departments with an increasing trend of acute respiratory disease, as
compared to 8 departments last week; its overall national trend was
decreasing. All of these countries are reporting a low or moderate
impact of acute respiratory disease on health care services.

Weekly summary
--------------
- influenza-like illness activity remained above what is expected for
this time of year in Canada and the United States; in Mexico, it
surpassed the level that was observed during the 1st wave of the pandemic
- Caribbean countries reported mostly unchanged trends but high
intensity of acute respiratory disease this week
- Central America continues to report overall decreasing trends in
acute respiratory disease
- Most of South America had stable or decreasing trends of acute
respiratory disease, with the exception of Colombia and Peru, which
reported an increasing trend
- Venezuela reported that the outbreak of acute respiratory illness
in the Yanomami communities has ended
- a median of 99.9 percent of subtyped influenza A viruses were
pandemic (H1N1) 2009
- 294 new confirmed deaths in 8 countries were reported; in total
there have been 4806 cumulative confirmed deaths.

Descriptions of hospitalizations and deaths among confirmed cases of
pandemic (H1N1) 2009
----------------------------------------------------------------------
A table containing case counts reported to PAHO can be accessed via
the source URL above.

Approximately half of hospitalized cases were among women. Children
continued to be the age group with highest hospitalization rates.
Underlying co-morbidities were present in approximately half of
hospitalized cases.

Overall, approximately half of deceased cases were among women. In
the Dominican Republic, however, 82 percent of their 22 deaths were
among women and approximately 67 percent of deaths among women were
in pregnant women. The percentage of cases with underlying
co-morbidities varied from 58.3 percent to 76.1 percent.

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. Pandemic (H1N1) 2009
continues to predominate among circulating subtyped influenza A viruses.

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, 277 samples submitted from 18
countries were found to be sensitive to neuraminidase inhibitors
(oseltamivir and zanamivir). In the United States, a total of 15
cases of oseltamivir-resistance have been identified. Of the 15
oseltamivir-resistant cases, 13 had documented exposure to
oseltamivir, one case had no documented oseltamivir-exposure, and one
case is under investigation.

As of 13 Nov 2009, a total of 4806 deaths have been reported among
the confirmed cases in 27 countries of the Region.

In addition to the figures displayed in the table available at the
URL above, the following overseas territories have confirmed deaths
of pandemic (H1N1) 2009: United Kingdom Overseas Territories; Cayman
Islands (1 death); French Overseas Communities: Martinique (1 death);
Guadeloupe (1 death).

The distribution of cases and deaths at the 1st sub-national level
can be found in the interactive map available through the following
link: .

--
Communicated by:
ProMED-mail Rapporteur Marianne Hopp

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