A previously unknown strain of an Asian virus carried by rodents has been found in at least two victims of the flu epidemic that killed 16 people in Southwestern states, the U.S. Centers for Disease Control and Prevention reported Thursday.
The agency said it is now defining confirmed cases in the epidemic that mainly has hit Navajo Indians in New Mexico.
The CDC last week said it suspected a previously unknown strain of a hantavirus in the epidemic in which victims typically come down with fever, headache and cough quickly followed by respiratory failure.
In the latest editions of its "Morbidity and Mortality Weekly Report," the CDC said doctors confirmed the existence of hantavirus disease in seven people, four of whom had died.
The agency said it is investigating another 23 suspected cases, 12 of them fatalities.
California health officials said Wednesday two people had died and five others became ill in the state with a respiratory illness similar to the flu in the Southwest.