DIVERSITY OF BABESIA INFECTING DEER TICKS (IXODES-DAMMINI)

To determine whether the presence of nonpathogenic piroplasms may conf ound field estimates of risk of Babesia microti infection, we identifi ed sporozoites infecting the salivary glands of deer ticks (Ixodes dam mini) by parallel microscopy and polymerase chain reaction assays. Pir oplasms were evident in 14.4% of adult ticks from sites in the northce ntral and northeastern United States. Of these, 83.3% contained DNA ch aracteristic of Ba. odocoilei. This cervid piroplasm was detected in a ll of the sites examined and generally was more prevalent than was Ba. microti. Because deer ticks transmit both Ba. odocoilei and Ba. micro ti, estimates of pathogen prevalence based solely on microscopy may ov erestimate the risk of human babesiosis.