Mexican swine flu victims were young

By Maggie Fox, Health and Science Editor

WASHINGTON (Reuters) - Swine flu patients in Mexico were young and many were healthy before developing severe infections, doctors reported on Monday.

The first detailed studies of the outbreak of a new strain of H1N1 influenza show the epidemic in Mexico resembled the early stages of other pandemics, and showed there is no way yet to predict who will become severely ill from the virus.

The World Health Organization has confirmed 70,893 cases in the new H1N1 swine flu pandemic, with 311 deaths. However, U.S. health officials last week said there were likely at least a million cases there alone. Iraq, Lithuania, Monaco and Nepal all confirmed their first cases on Monday.

Dr. Rogelio Perez-Padilla of the National Institute of Respiratory Diseases in Mexico City and colleagues studied 18 H1N1 cases in March and April, more than half of them aged 13 to 47.

Only eight had pre-existing medical conditions that might worsen their flu infection, they wrote -- including high blood pressure, diabetes, asthma and sleep apnea. Seven died -- all of multiple organ failure.

The doctors said 90 percent of the seriously ill patients were under 50 -- in contrast to seasonal influenza, which causes mostly mild illness in people under the age of 65.

"Most of our patients were young to middle-aged and had previously been healthy," they wrote in their report, published in the New England Journal of Medicine.

"One contributing factor for death in our patients may have been delayed admission and delayed initiation of oseltamivir."