Washington: Adolescents and relatively healthy adults are especially at risk from the swine flu, which is associated with respiratory failure and a high mortality rate in serious cases, a latest study has said.
The study, conducted during the first phase of infection between March 18 and June 1 in Mexico and April 16 through August 12 in Canada, also shows how emergency services
were sometimes submerged by the number of serious cases that needed to be treated simultaneously.
At least 4,525 people have died from swine flu infections since April and there have been over 378,223 laboratory-confirmed cases, the World Health Organisation said
Friday, with most deaths occurring in the Americas.
"Our analysis of critically ill patients with 2009 influenza A(H1N1) reveals that this disease affected a young patient group," wrote the authors of the study led by
Guillermo Dommnguez-Cherit of the Instituto Nacional de Ciencias Midicas y Nutricisn in Mexico City.
"Early recognition of disease by the consistent symptoms of fever and a respiratory illness during times of outbreak" accompanied by "prompt medical attention," the
authors said, "may provide opportunities to mitigate the progression of illness and mortality observed in Mexico."
In "almost all cases," fever and respiratory symptoms were harbingers of disease, they added.
"There was a relatively long period of illness prior to presentation to the hospital, followed by a short period of acute and severe respiratory deterioration."