The case of a 9-year-old Georgia boy who contracted a rare tick-borne disease called ehrlichiosis from a blood transfusion can be considered the first instance of such transmission, said the CDC's Dr. Joanna Regan. The rare disease, which is not routinely screened for, can be potentially fatal, Regan said. Health officials traced the infection to a blood donor in Florida. Eight other people were found to have received transfusions of the donor's blood; five tested negative for the tick-borne disease while the other three died from unrelated causes. The findings were published in the journal Clinical Infectious Diseases.