Chiron Wins Bird Flu Vaccine Deal  WASHINGTON (Reuters) - Chiron Corp. &lt;A HREF="http://www.investor.reuters.com/FullQuote.aspx?ticker=CHIR.O target=/stocks/quickinfo/fullquote"&gt;CHIR.O&lt;/A&gt; has won a  contract to develop a human vaccine against a strain of bird  flu that can infect people and "has the potential to trigger a  modern-day pandemic," the U.S. government said on Tuesday.