Did you know the Western fence lizard (Sceloporus occidentalis) has a borreliacidal effect on ticks carrying the causative agent of Lyme disease, Borrelia burgdorferi? This means that an enzyme in lizard blood kills the Borrelia pathogen carried in the tick when it ingests the blood. According to researchers, this is most likely due to the presence of a thermolabile protein that destroys Borrelia in the midgut diverticula of feeding ticks. Interestingly, a thermolabile hemolytic agent (complement) exists in turtle serum, but it’s function has not been widely studied. Of all the ticks I identified, I took a subset of 170 ticks collected from tortoises and analyzed them for Borrelia. However, no ticks tested positive for Borrelia spp. One blood sample from a technician that contracted tick-borne relapsing fever after being bit by an Ornithodoros tick in the same habitat in which the 170 ticks were collected from resident, wild tortoises tested positive for Borrelia spp. This sample was sequenced to Borrelia turicatae using the IGS gene. From this preliminary data, we hypothesize that desert tortoises may have a borreliacidal factor in their blood that kills Borrelia spirochetes.