Prevalence of Rocky Mountain Spotted Fever in Kittitas County Ticks

Author(s)

Raeanne Tegman

Faculty Mentor(s)

Gabrielle Stryker (Biological Sciences)

Abstract

Rickettsia rickettsii is a pathogenic bacterium that causes Rocky Mountain spotted fever in individuals who have been the recipient of a tick bite. Rocky Mountain spotted fever causes fever, headache, rashes, and can be deadly in those who do not receive proper treatment. In the North Eastern part of the United States, tick surveillance is a common method used to identify the prevalence of pathogenic bacteria. In Washington State, however, the detection of this pathogenic bacterium is primarily based on human incidence. My project focused on identifying the prevalence of R. rickettsii in the Kittitas County tick population. Methodology include dragging known tick areas for collection of specimens, donations of ticks from local residents, and DNA sequencing for detecting pathogenic bacteria. The ticks collected were identified by comparison of mouth and body signatures to known species, which resulted in the identification of two tick genera, Ixodes and Dermacentor. After DNA extraction, Polymerase Chain Reaction (PCR) was performed in order to identify the presence of R. rickettsii. Results confirm the presence of this bacterium in at least one tick. A number of ticks indicated the possibility of infection, but more research must be done in order to confirm.

Keywords: Tick, Bacteria, Disease

Presentation

15 thoughts on “Prevalence of Rocky Mountain Spotted Fever in Kittitas County Ticks”

  1. Firstly I want to mention, you did an amazing job on this presentation! You did a great job conveying your topic so people could understand it without taking the necessary complexity of the content out. Also, I am in awe of your visuals in your presentation, the tick banner of your actual ticks was such a unique touch! My question for you would be, in your presentation, you mentioned potentially sending tick 6 (I think) on for further testing for the R. rickettsii, do you know what sort of testing the other lab might have done to validate your results beyond what you did?

    1. Hi Alexis! I would send the R. rickettsii DNA that I collected from tick 6 to the lab, and I believe that they would sequence it in order to confirm that the DNA is indeed from the pathogen.

  2. I loved the little ticks along the bottom of your slides. A very interesting projects — impressive, especially given COVID restrictions

  3. Awesome presentation, Raeanne! Fascinating findings. I would be curious to hear more about your results when you are able to test the other ticks that may have been positive for R. r. Additionally, well done being able to adjust your study as COVID-19 impacted your ability to conduct research in the original way you had intended. This is excellent research. Bravo!

    1. Hi Kyle! Thanks for taking the time to watch my presentation. I am also very interested to see if any of the other ticks test positive.

  4. Good job changing gears and finding another project to do. Your enthusiasm for research shines through in your voice and your visuals (nice slides). Question: tick 11 also looked like it had a bright band at around 500 bp. Was this not likely to be R. ricketsii because of the multiple bands caused by low annealing temperature? I’m also curious since at least one of your ticks may have had the R. ricketsii bacterium, are there any documented cases of people getting Rocky Mountain spotted fever in Kittitas County?

    1. Hello! Thank you so much. I really enjoyed working in the lab and had so much fun learning how to catch ticks. Tick 11 could also be positive for R. rickettsii. I would also like to rerun this tick in order to confirm. Tick 11 was an Ixodes pacificus tick which means that it is capable of carrying Lyme disease. Testing indicated that it was negative.

      I am not aware of any positive cases of R. rickettsii in Kittitas County. Seattle.gov states that in 2019 there were 3 positive cases in the state, but it does not indicate the counties. There is very little research on tick borne pathogens in Washington, most likely because they are not as prevalent here compared to the east coast.

  5. Great job on your presentation! Based on your results, how much of an issue do you think Rocky Mountain Spotted Fever will be in the county?

    1. Hi Paul! My results indicate that R. rickettsii is most likely in the county. I think it is important to spread awareness about this finding (when confirmed by the lab) because there are many hiking trails that put people at risk of contracting the pathogen if they are not careful.

  6. Racheal Croucher

    Great presentation Raeanne! It was interesting to me that tick #6 was (the only?) female and tested positive for R.r. while the males were all inconclusive or negative. Has there been research to see if these ticks are equally likely to carry the bacteria across sex?
    Thank you for explaining all of this at a level that I can understand with zero exposure to this in the past.

  7. Incredible job Rae! I was surprised to learn that dog ticks don’t carry Lyme disease, but are the vector for Rickettsia. When collecting ticks, were any of them found on yourself or anyone collecting with you?

  8. Wow, excellent presentation RaeAnne! Your research offers meaningful data to the community and was very well put together and delivered. I’m not particularly thrilled that tick number 6 came from my head after we went hiking, but at least I got it off of me and into the freezer before it bit me.

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