American Red Cross studying prevalence of rare, but growing, tick-borne parasite in donated blood

May 31, 2011

The Twin Cities-based North Central Blood Services Region of the American Red Cross is participating in a study of the parasite Babesia microti in healthy blood donors in areas of Minnesota and western Wisconsin. Although tick-borne in nature, Babesia is also transmissible by blood transfusion, which is of growing concern for the Red Cross as it can potentially be harmful to patients who are already immunocompromise.

Information collected in the study will help to determine the prevalence of Babesia in blood donors and support the development of effective blood-screening strategies and blood donor management policies. There currently is no Food and Drug Administration (FDA) approved rapid test for Babesia available to blood centers.

“Safety is our top priority,” said David Mair, M.D., senior medical director of the North Central Blood Services Region. “The blood supply is safer today than it has ever been. Through efforts like this, along with the support of our generous blood donors, blood drive volunteers and dedicated staff, we can help ensure it remains as safe as possible.”

Some people infected with Babesia, transmitted primarily by common deer ticks, develop Babesiosis, a hemolytic disease, and suffer from malaria-like or flu-like symptoms, such as chills, anemia, fatigue, nausea, night sweats and fever. Other infected, but otherwise healthy, adults are asymptomatic. Babesiosis can be treated with antibiotics.

An estimated 70 cases of clinical infections of Babesia transmitted through blood transfusions were reported to the FDA from 1979 to 2007, most within the last 10 years. Approximately 30 million blood products are transfused in the United States annually to about five million patients.

Dr. Mair initiated the Babesia study in collaboration with the Holland Laboratory in Rockford, Maryland, the research and development arm of American Red Cross Biomedical Services. The Minnesota Department of Health provided data to help identify the most endemic areas of Minnesota where the Red Cross has blood drives.

“Although some studies of Babesia have been conducted in the northeastern parts of the United States, few studies have been done in the Upper Midwest where Babesia is also known to be endemic,” said Dr. Mair. “Because the range of Babesia is expanding, our concern has grown for the potential transmission of the parasite by blood transfusion.”

“Studies done in the northeastern part of the U.S. showed the prevalence of Babesia ranging from 0.3 percent in the general population to 9.5 percent in patients with Lyme disease,” said Dr. Mair. “Our study will increase our understanding about the prevalence of Babesia in the Upper Midwest.”

Two thousand blood donors will be tested for exposure to Babesia at American Red Cross blood drives in Minnesota and one county in western Wisconsin through the fall of 2011. To be included in the study, donors must be 17 years of age and older and consent to the additional test.

If a blood donor tests positive for exposure to Babesia or tests positive for Babesiosis, they will be notified by the Red Cross and deferred from donating blood again to protect the safety of the blood supply. Dr. Mair acknowledges this may be disappointing for some committed blood donors, but says there are benefits for donors. “I’m confident they will appreciate the additional health screening and can take appropriate measures with their primary care physician to ensure their own good health if they test positive,” he added.

About the American Red Cross

Governed by volunteers and supported by giving individuals and communities, the American Red Cross is the single largest supplier of blood products to hospitals throughout the United States. While local hospital needs are always met first, the Red Cross also helps ensure no patient goes without blood no matter where or when they need it. In addition to providing nearly half of the nation’s blood supply, the Red Cross provides relief to victims of disaster, trains millions in lifesaving skills, serves as a communication link between U.S. military members and their families, and assists victims of international disasters or conflicts.