Through the early and middle part of April, an unusual cluster of respiratory illness appeared in the Mexico City area, an area of approximately 10,000,000 people. Attempts to identify this illness pointed to an influenza event, but testing could not identify the type. Eventually, the influenza was typed as a novel strain of H1N1 (formerly referred to as swine influenza).
 
Since that time, the World Health Organization has identified 2099 cases of novel H1N1 influenza in 23 countries (as of May 6th). Thus far, 29 deaths have been reported in Mexico and two in the United States. In many cases, the individuals who died had additional comorbidities. The overwhelming majority of infections have been mild and self-limiting with the majority of individuals recovering at home.
 
The current round of infections may be seen as the first wave of this illness. If the past is any indicator, additional waves of this strain may be expected in the coming months and have the potential to be more virulent, affecting many more individuals with serious illness.

 

At the present time, the World Health Organization has declared a Pandemic Level of 5.  This level indicates pandemic preparedness plans should be activated and agencies should remain on high alert for unusual outbreaks of influenza-like illness. This level also encourages heightened surveillance, early detection and treatment of cases and infection control in all health facilities.