WASHINGTON- People with signs of West Nile infection, including headache and fever, should be barred from donating blood until nearly two months after the symptoms wane, federal health officials proposed Friday.

A Food and Drug Administration official briefed the agency’s Blood Products advisory committee about the recommendation. Depending on its effect on the blood supply, the guidance could be finished as early as this fall.

Already, West Nile is racing through this summer’s hot spots, sickening and killing people in Arizona, California, and Colorado. Sensitive tests have tagged 61 potentially infected donors, whose blood donations were yanked from shelves, Hira Nakhasi, director of the FDA’s Division of Emerging and Transfusion Transmitted Diseases, told the advisory committee.

Typically, those donors could not make another blood donation until 28 days after their first symptoms of West Nile. That deferral period was based on 1950s research that indicated West Nile virus could remain in the body for 28 days.

The American Red Cross, testing samples from the 2003 West Nile epidemic, found the infectious virus could linger in blood for up to 49 days.

Within the FDA, researchers are mulling a change that would postpone potential donations until 56 days after West Nile diagnosis or symptoms consistent with the mosquito-borne ailment.