14 TB Polo Horses Mysteriously Drop Dead

[Merlinsky]

http://www.cnn.com/2009/US/04/19/dead.horses/index.html

What could hit them all that fast? Something airborne? Some 40-60 total horses get cycled through per team during a match it said. You'd think there'd be signs of illness sooner than 2 collapsing if were something like West Nile.