CDC Sounds Warning of Tickborne Parasite, Babesia, Spreading by Blood Transfusions
Elderly among those most in endangered; screening of donors needed but no FDA approved systems
Sept. 6, 2011 – Babesia, a parasite transmitted to humans by tick bites is endangering the U.S. blood supply, since the
disease babesiosis is also spreading through transfusions and is potentially fatal, according to the Centers for Disease Control and
Prevention. The agency, which in January required states to report the disease, is calling for donor screenings but there is currently no
testing approved by the Food and Drug Administration.
According to results of a collaborative study led by the CDC of data from the past three decades, transfusion–associated
cases of babesiosis have been increasingly recognized since 1979, the year the first known case occurred.
In the report, CDC and collaborators describe 159 transfusion–related babesiosis cases that occurred during 1979–2009,
most (77 percent) from 2000 to 2009. No babesia test approved by the Food and Drug Administration is available for screening prospective blood
donors, who can feel fine despite being infected.
Babesiosis is a potentially fatal but treatable complication of transfusion. Severe consequences, such as multi–organ
failure and death, are most often seen in the elderly, persons without a spleen and those with a weak immune system.
The study authors say prevention strategies, including development of a screening test, are needed. Some manufacturers
are working with investigators at blood establishments to develop FDA–approved tests for Babesia for donor–screening purposes.
“We want clinicians to become more aware of babesiosis, including the small possibility of transmission via blood
transfusion,” says Barbara Herwaldt, M.D., M.P.H., CDC medical epidemiologist, and lead author of the article.
“If a patient develops unexplained fever or hemolytic anemia after a transfusion, babesiosis should be considered as a
possible cause, regardless of the season or U.S. region.”
Because babesiosis is spread most commonly by ticks, the risk of this disease is another reason for people to prevent
tick bites. People who unknowingly become infected through the bite of a tiny tick (about the size of a poppy seed) can transmit the parasite
via blood transfusion. Therefore, prevention of tickborne infection can help safeguard the blood supply.
Most Tick Bite Cases in 7 States
Most U.S. tickborne Babesia cases have occurred in seven states in the Northeast and the upper Midwest (in parts of
Connecticut, Massachusetts, Minnesota, New Jersey, New York, Rhode Island, and Wisconsin), particularly during the warm months of the year.
However, transfusion–associated Babesia cases have been identified in 19 states and have occurred year–round.
Dr. Herwaldt points out that even severe Babesia cases, not just cases that are asymptomatic or mild, are easily missed
unless the diagnosis is considered. Even then, babesiosis often is mistakenly diagnosed as malaria, which also infects red blood cells.
In January 2011, babesiosis became a nationally notifiable disease, which means state health departments are encouraged
to share information about cases of babesiosis with CDC. More accurate information about tickborne and transfusion–transmitted cases of
babesiosis will help CDC and its partners, including the FDA, in their continued efforts to make the blood supply even safer.
Links:
>>
Annals of Internal Medicine
See links below for two government–sponsored events that focused on improving blood safety from babesiosis risk.
>> Information on
babesiosis
>> Information on the
Babesia
parasite
>>
Information on FDA public workshop
>>
Information on the Blood Products Advisory Committee meeting
>> Information on ticks:
http://www.cdc.gov/ticks/
>> For information on CDC’s roles in monitoring blood safety:
http://www.cdc.gov/bloodsafety
