Mystery flu hits Southwest.

A virus carried by field mice and other rodents may prove responsible for the deadly flu-like illness that has erupted mostly in Arizona and New Mexico, according to public health officials.

The ailment, which is known as acute respiratory distress syndrome, has killed 11 people and made nine others, severely ill. The symptoms appear remarkably like those of the flu. Victims spike a fever, start coughing, and develop muscle aches and inflamed, reddened eyes. Most, although not all, of the victims lived on or near the Navajo reservation located in the Four Corners area of Arizona. New Mexico, Utah, and Colorado.

The illness primarily has hit apparently healthy people in their 20s and 30s, says epidemiologist Stuart Castle of the New Mexico State Health Department in Santa Fe. Patients have trouble breathing, and some have died of suffocation within hours of getting ill, he adds.

U.S. Department of Health and Human Services Secretary Donna E. Shalala has sent federal investigators to help state and local epidemiologists nab the culprit in this deadly cluster of cases. Preliminary evidence suggests that the illness is caused by airborne spread of dried urine or fecal matter from rodents infected with some type of virus, possibly a Hantavirus. Health officials have urged people living on or near the reservation to avoid rodent nests.

The disease does not appear to be transmitted by contact with infected people, Castle adds. No health workers have become infected. Furthermore, the investigators turned up only one instance in which several members of the same family got sick.