Correct me if I am wrong, but aren't they supposed to screen the blood before giving it to another person?

Of the 162 cases of Babesia infection caused by blood transfusions between 1979 and 2009, nearly 80 percent occurred between 2000 and 2009.

"Babesia microti has become the most frequently reported transfusion-transmitted parasite in the United States," CDC researchers wrote, far outpacing malaria infections, which accounted for 49 cases of transfusion-associated disease during the same period, including just five cases during 2000-2009.

Scary.