Abstract
During the late summer of 1940, 49 lots of Ornithodoros ranging from 1 to 59 specimens were collected in San Juan, Grand, Uintah, Carbon, Emery, and Iron Counties. Earlier collections had included Washington and Wayne Counties. One specimen from San Juan County proved to be O. turicata, the first record for this species in Utah. The remaining ticks were O. parkeri. Spirochetes were recovered from lots representing Uintah, Grand, Carbon, and Emery Counties. White mice, white rats, and guinea pigs were susceptible to one of the strains. Relapses occurred in all 3 host spp. Two cases of relapsing fever have been reported in the State.