The only recorded case of HIV transmission from a blood transfusion in the last eight years has been linked to a Missouri blood donor, according to a federal report.

A man in his 40s donated contaminated blood at a Missouri blood center in June 2008, according to the report released Thursday by the Centers for Disease Control and Prevention.

The man's HIV positive status was not confirmed until after he donated blood a second time, in November 2008. The contaminated blood was destroyed and the man was prohibited from future donations.

In the meantime, investigators found that the man's blood from the first donation had been transfused into two patients. One patient in Arkansas died of heart disease two days after receiving a transfusion during a July 2008 surgery, and it is unknown whether the patient contracted HIV. The second patient, of Colorado, received a blood transfusion during a kidney transplant in August 2008 and later tested positive for HIV.

Lab results confirmed that the blood transfusion was the cause of the HIV infection in the kidney transplant patient. The last known case of HIV transmission from a blood transfusion was in 2002.

Before both blood donations, the Missouri man told health care workers that he did not have any risk factors for HIV. In a follow-up interview with the Missouri Department of Health and Senior Services, the man acknowledged having anonymous sexual affairs with men and women before his initial blood donation.

Men who have ever had sex with another man have been banned from donating blood since the early 1980s, a policy upheld in June by a federal review panel.

Health investigators determined that the man had donated blood during the window of time before HIV infection can be detected though screening. That window averages nine days for the tests used by U.S. blood banks.

The risk of contracting HIV from a blood transfusion is about 1 in 1.5 million, according to CDC estimates.

"Even the most sensitive screening technologies currently available cannot identify the presence of HIV infection during the first few days after infection," the report concludes. "Eligibility screening questions, if answered accurately, would have excluded the donor because of his sexual history. It is the responsibility of persons who donate blood to answer screening questionnaires accurately to ensure the safest blood supply possible."

The report is being published today in the CDC's Morbidity and Mortality Weekly Report.