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Ticks carry more than Lyme disease in California – are Californians at risk?

University of California Davis
Santa Cruz, California
DOI: 10.18258/7615
Grant: Wildlife Diseases
Funded on 11/05/16
Successfully Funded
  • $4,101
  • 102%
  • Funded
    on 11/05/16

About This Project

The western blacklegged tick carries the pathogens B. burgdorferi (cause of Lyme disease) and B. miyamotoi (cause of a relapsing fever (RF) illness). B. miyamotoi has been documented in Californian ticks, but human disease has yet to be detected. With a recent study showing that B. miyamotoi may survive under standard blood bank conditions, our research proposes to describe the emerging disease potential of B. miyamotoi.

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What is the context of this research?

B. miyamotoi has been detected in all species of Lyme disease tick vectors. In California ticks, the prevalence of B. miyamotoi is similar to that of B. burgdoferi. Though human cases of B. miyamotoi have been reported from Russia, Europe, Japan, and the eastern US, paradoxically none have been documented in the western US. A related Borrelia transmitted by soft ticks, B. hermsii, also causes a RF disease in mountainous areas in the western US and can cross react with Borrelia testing. A study suggested that B. miyamotoi can be a blood transfusion risk as it survives in human blood under standard conditions1. With strategic sampling of human sera from blood banks, this study will address the emerging nature and demographics associated with B. miyamotoi exposure in California residents.

What is the significance of this project?

The frequency and distribution of relapsing fever caused by B. miyamotoi in humans in California is unknown. There are no widely commercially available tests for B. miyamotoi infections. By testing for antibodies for B. miyamotoi in blood bank donors from high incident counties of Lyme disease in CA this research study intends to establish that humans are exposed to B. miyamotoi in CA. Results will potentially allow for an alternative diagnosis of B. miyamotoi infection among people with Lyme- like symptoms and negative Lyme laboratory test results and results, can further direct epidemiological studies and public health messaging.

What are the goals of the project?

The moneys raised will fund the cost of obtaining human blood from a commercial blood bank, shipping, and testing.This is a multi-institutional project, including UC Davis, UC Irvine, and the California Department of Public Health. Specifically we will obtain 500 human serum samples from blood banks from high incident counties for Lyme disease where people are risk of bites from Borrelia-infected ticks. Five hundred samples will provide adequate probability to detect an anticipated prevalence of 1%. All human sera will be tested for antibodies against B. miyamotoi and B. burgdorferi. The results of this seroprevalence study will be published and will be an essential first step in describing human B miyamotoi epidemiology in California.


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The moneys raised will fund the cost of obtaining human sera from a commercial blood bank, shipping, a nd testing. This is a multi-institutional project, including UC Davis, UC Irvine, and the California Department of Public Health. Specifically we will obtain 500 human serum samples from blood banks from high incident counties for Lyme disease where people are risk of bites from Borrelia-infected ticks. 500 human serum samples at about $4.00 per = $2000.00. All human sera will be shipped and tested for antibodies against B. miyamotoi and B. burgdorferi at the University of California Irvine Shipping and Testing = $2000.00.

Endorsed by

A top-notch team has been assembled for this project to identify human exposure Borrelia miyamotoi in California. Previous work has already identified this agent in ticks- this study is the first of its kind to assess where and how often Californians may be exposed to B. miyamotoi . This is important because it will impact awareness and diagnosis of this newly emerging tick-borne relapsing fever as well as other tick-borne diseases, including Lyme disease. It is exciting to be involved with this important project.
I enthusiastically support this project as an important step in our understanding of Borrelia miyamotoi in California. Tick surveillance suggests a similar risk of this spirochete in California ticks as in other geographic regions where B. miyamotoi has been detected in people.
I am pleased to endorse this project with high enthusiasm. Borrelia miyamotoi is an emerging tick-borne bacterial agent that is widespread in the western black-legged tick. The project proposed here should increase our knowledge as to how often and in what geographical regions this bacterium infects and causes human illness in California.
Borrelia miyamotoi, a cause of a relapsing fever-like illness, is as common as Borrelia burgdorferi, the cause of Lyme disease, in the western blacklegged tick in northern California. But there has been no study of the exposure of people to Borrelia miyamotoi in California. This study would not only be the first to do that, but it would also investigate exposure to the Lyme disease and estimate the frequency of dual infections as well.

Meet the Team

Sharon Brummitt
Sharon Brummitt
PhD student Epidemiology


University of California Davis
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Team Bio

Anne Kjemtrup, DVM, MPVM, PHD: California Department of Public Health Vector-Borne Disease Section for over 15 years. She is the subject matter expert for many of the vector-related reportable diseases.

Alan Barbour, MD: Professor University of California Irvine

Woutrina Smith, DVM, MPVM, PHD: Associate Professor of Infectious Disease Epidemiology in the School of Veterinary Medicine at University of California Davis. Her research utilizes a One Health approach locally and globally.

Sharon Brummitt

I am a second year PhD student in Epidemiology at UC Davis with my primary research focus on the science of surveillance systems, particularly pertaining to borreliosis. I became interested in the surveillance of infectious diseases during my practicum as a Master’s student at the University of Texas School of Public Health (UTSPH) where I participated in an epidemiological investigation of one of the largest outbreaks of cryptosporidiosis in Dallas, Texas. As a result of the investigation, Senate Bill 968 was passed in an effort to prevent future outbreaks of waterborne illnesses associated with interactive fountain parks. After earning my MPH, I obtained the prestigious California Epidemiologic Investigation Services (Cal-EIS) fellowship with the California Department of Public Health from 2010 to 2012 in applied epidemiology. As a Cal-EIS fellow, I was the lead investigator for all reported tick borne diseases in the county of Santa Cruz as well as performing case investigations for other notifiable and reportable conditions. My enthusiasm and momentum grew when I identified an unusual case of Lyme disease and facilitated obtaining synovial fluid from the patient. In collaboration with the California Department of Public Health and UC Irvine, Borrelia burgdorferi was isolated from the synovial fluid and molecularly characterized to produce novel findings. This finding was published in Emerging Infectious Diseases because it represented the first Lyme disease case in California where the isolate was genotypically characterized as unique to ticks from California. I also presented these findings at the Northern California Parasitologist Conference in 2016. My future goals are to complete and obtain my PhD in Epidemiology from UC Davis and apply my research skills in the development of future research which could foster and aid the scientific community.

Project Backers

  • 32Backers
  • 102%Funded
  • $4,101Total Donations
  • $128.16Average Donation
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