(AP) -- Health officials say a unique type of swine flu has now been diagnosed in seven people in California and Texas, up from the two reported earlier this week. The five new cases in the two states have all recovered, and testing indicates some mainstream antiviral medications work against the virus.
But it's a growing medical mystery: Only a few of the seven people were in contact with each other, and none were in contact with pigs.
U.S. Centers for Disease Control and Prevention officials said Thursday they are expanding their investigation.
©2009 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.
Explore further: Rare cause of anemia in newborns often overlooked, research suggests