ENTOMOLOGICAL CORRELATES OF BABESIA-MICROTI PREVALENCE IN AN AREA WHERE IXODES-SCAPULARIS (ACARI, IXODIDAE) IS ENDEMIC

Zoonotic prevalence of Babesia microti Franca piroplasms infecting whi te-footed mice, Peromyscus leucopus Rafinesque, was determined at 34 s ites in Rhode Island where nymphal blacklegged tick, Ixodes scapularis Say, densities ranged from low to hyperabundant (1.7-525.3 nymphs per hour of flagging). Babesia was only detected at sites where tick abun dance was moderate to high (>20 nymphs per hour of flagging) and appea red to exhibit a clumped distribution. Where B. microti was detected, the mean number of nymphal ticks collected per hour of flagging was 22 9.2 compared with a mean of 40.1 at sites where Babesia was not detect ed. By combining the spatial occurrence of Babesia with a tick density database in a geographic information system, it may be possible to pr edict the pattern of zoonotic and human infection with B. microti.