|Influenza cases by a new sub-type: Regional Update (1 May 2009 )|
To date, the United States has confirmed a total of 141 human cases of influenza A (H1N1): 4 in Arizona, 13 in California, 2 in Colorado, 4 in Delaware, 3 in Illinois, 3 in Indiana, 2 in Kansas, 1 in Kentucky, 2 in Massachusetts, 2 in Michigan, 1 in Minnesota, 1 in Nebraska, 1 in Nevada, 5 in New Jersey, 50 in New York, 1 in Ohio, 16 in South Carolina, 28 in Texas and 2 in Virginia. Other suspected cases are being investigated. 6 hospitalizations and a death have been registered. The dead case is a child of 22 months old. The age range of the confirmed cases is from 22 months to 81 years (a median of 16 years). The most recent cases detected as well as the registered death suggest that more serious cases could appear in the United States.
From 17 to 30 April, Mexico has reported 2,387 suspected cases of influenza with severe pneumonia including 92 deaths. The suspected cases were recorded in all Mexican states. The most affected are: Aguascalientes, Baja California, Distrito Federal, Durango, Estado de México and San Luís Potosí. The majority of these have occurred in previously healthy young adult people. There have been few cases in individuals under 3 or over 59 years old. 982 of the suspected cases have required hospitalization.
The number of probable cases of influenza A (H1N1) is 528. 156 cases have been confirmed, with 7 death cases among them. The considerable variation in the number of confirmed cases as of today is due to the recent laboratory confirmation of samples collected in previous weeks.
In Canada, to date 34 human cases of influenza A (H1N1) have been confirmed (6 in Alberta, 8 in the province of New Scotland, 11 in British Columbia, 1 in Quebec and 8 in Ontario) some of them with recent trip history to Cancun, Mexico. All the cases developed a mild form of influenza like illness. 2 of the cases presented, in addition, gastrointestinal symptoms. All of them are currently recovered and none required hospitalization. Laboratory tests were conducted in Winnipeg, Canada. `Indigenous` transmission is not discarded since not all the confirmed cases have trip history to Mexico
The press has reported information on suspected cases in several countries of the Region; however this information has not been confirmed.
At the request of the Director-General (DG) of WHO, the IHR Emergence Committee has been summoned and is advising the DG on the event. On its first day of deliberation, 25 April, it concluded that the present event constitutes a Public Health Emergency of International Concern.
On 29 April 2009, the DG decided to elevate the pandemic alert to Phase 5. In order to come to this urgent decision, the DG considered epidemiological information from the most affected countries, as well as the result of the scientific meeting held that same day. The latter indicated the existence of sustained outbreaks of influenza A (H1N1) at the community level in more countries within the Region.
The decision to increase the pandemic level of the alert should permit Member States to provide the required leadership and coordination as well as to consider the possibility of executing their contingency plans.
The DG recommends not closing borders or restricting travel. However, it is prudent for people who are sick to delay travel. Moreover, returning travelers who have become sick should seek medical attention in line with guidance from national authorities.
Production of seasonal vaccine should continue, but at the same time, WHO is making all the efforts to facilitate the process of development of a vaccine against influenza A (H1N1).
The Committee will continue to advise the DG on the basis of the available information.
At this time, enhanced surveillance is recommended. On its Web page, PAHO has published orientations for the enhancement of surveillance activities, which are directed to the investigation of:
The following risk factors should also cause suspicion of influenza A (H1N1):
It is recommended that National Influenza Centers (NIC) immediately submit to the WHO Collaborating Center for influenza (CDC of the United States) all positive but unsubtypable specimens of influenza A. Shipment procedures are the same as those used by NICs for seasonal influenza specimens.
The test protocols for the detection of seasonal influenza by Polymerase Chain Reaction (PCR) cannot confirm influenza A (H1N1) cases. The Centers for Disease Control and Prevention of the United Sates are preparing testing kits that will include the primers and probes as well as the required positive control samples. The kits will be sent in the first week of May to those NICs that currently use the CDC protocol.
Since the main form of transmission of this disease is by droplets it is recommended strengthening the basic precautions to prevent their dissemination, for example the hygiene of hands, adequate triage in the health facilities, environmental controls, and the rational use of the personal protective equipment in accordance with the local regulations.
The complete guides “Epidemic-prone & pandemic-prone acute respiratory diseases Infection prevention & control in health-care facilities” are available at:
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Regional Office for the Americas of the World Health Organization