>>The Food and Drug Administration is considering changes to its blood-donor guidelines including increasing the time that people suspected of having or diagnosed with West Nile virus should be prohibited from giving blood.<<
Considering that anyone in many parts of the U.S. who has been bitten by a mosquito could be "suspected" of having West Nile virus, this could be a tricky ruling to enforce.
(And could substantially decrease the blood donor pool.)
>>Those who test positive for the mosquito-borne illness are also deferred for 28 days.<<