In February I was honored with the privilege to give a webinar about my research for the CDC's Zoonoses and One Health Update call. Check out a recording of my presentation, Ticks Tortoises and Tick-borne Relapsing Fever in the Mojave Desert, here: https://www.cdc.gov/onehealth/zohu/2020/february.html
Research Update!
I have been busy at work in the lab extracting DNA from ticks and using that DNA in molecular analyses to look for Borrelia in the hundreds of ticks I've collected from desert tortoises across the Mojave. While friends were spending their summertime at the beach or vacationing in Europe, I was learning more about the prevalence of tick-borne relapsing fever in the desert (...but I'm not bitter about that or anything). What I've learned? Well, the prevalence for Borrelia in the ticks I've collected from tortoises is really low (about 0.8%), meanwhile I've documented two cases of tick-borne relapsing fever in tortoise biologists that were bit by Ornithodoros ticks when they were digging through tortoise burrows. So, we know that Borrelia exists in Mojave desert tortoise habitat, but the ticks that are feeding from tortoises, don't seem to carry it. This adds to the evidence that tortoises really do have a Borreliacidal or Borrelia killing component in their blood.
In other news in the lab, I have started identifying my ticks by sequencing their genes! There are two species of tortoise ticks that parasitize tortoises (Ornithodoros parkeri and O. turicatae), but they are very difficult to tell apart. Why? Because you count the number of bumps, or mammillae on their backs using a microscope (see picture below of an Ornithodoros tick to see the tiny mammillae across it's back). O. parkeri has more mammillae than O. turicatae.
A picture of an Ornithodoros tick, taken by Z. Barrand
Even the literature has criticized this identification method as being subjective, which is why, with the help of scientists at U.C. Riverside, I am sequencing the genes of the ticks to definitively tell them apart. And my so far my molecular analysis to identify the ticks is working! Most of my gene sequences have matched to O. parkeri, which is consistent the G. Greene's work on tick identification of Mojave desert tortoises in the 80's. With these new findings I am excited to start work on my next aims in which I will determine if desert tortoise blood does in fact have a Borreliacidal component and creating a species distribution map of Ornithodoros ticks throughout the Mojave desert.
Electrophoresis gel showing the amplified region of the 16S gene found in tick DNA. This extracted DNA was then sequenced to the genes of Ornithodoros parkeri!
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Look here for an excellent article about the importance of maintaining our federal lands to ensure important scientific breakthroughs to public health.