Not limited to endemic states, seasons; most cases tied to red blood cell components
TUESDAY, Sept. 6 (HealthDay News) -- From 1979 to 2009, 159 Babesia microti (B. microti) transfusion-associated cases of Babesiosis were identified in the United States, and occurrence was not limited by season or region, according to a study published online Sept. 5 in the Annals of Internal Medicine.
Barbara L. Herwaldt, M.D., M.P.H., from the U.S. Centers for Disease Control and Prevention in Atlanta, and colleagues examined data on transfusion-associated Babesia cases in the United States. A total of 159 patients who were transfused between 1979 and 2009, and had a post-transfusion infection of Babesia by 2010, without any evidence that transmission took place through any other likely route, were included in the study. Distribution according to Babesia species, period, and state of transfusion were documented.
The investigators found that the donor was implicated in 86 percent of the B. microti transfusion-associated cases. The median age for the case patients was 65 years (range, <1 to 94 years). Most cases were linked to red blood cell components, but whole blood-derived platelets accounted for four cases. Cases occurred in all four seasons of the year and in 22 of the 31 years of the study period, with 77 percent of the cases occurring between 2000 and 2009. The cases occurred in 19 states, but the seven main B. microti-endemic states contributed 87 percent of the cases. In Western states there were three documented B. duncani cases.
"Babesiosis should be included in the differential diagnosis of unexplained post-transfusion hemolytic anemia or fever, regardless of the season or U.S. region," the authors write.