Artificial Infection of Ticks with Borrelia burgdorferi Using a Microinjection Method and Their Detection In Vivo Using Quantitative PCR Targeting flaB RNA
Borrelia burgdorferi is maintained in nature by a tick-rodent infection cycle where it traverses and colonizes a variety of host and vector tissues. A tick-borne murine model has been developed to study Lyme disease in the laboratory, which has a substantial impact in advancing our knowledge of spirochete infectivity and pathogenesis. Here, we detail a microinjection-based method for rapid and efficient infection of ticks with B. burgdorferi. While laboratory generation of B. burgdorferi-infected nymphs via natural larval engorgement on infected hosts and subsequent molting could take several weeks to months, the microinjection-based infection procedure requires only a few hours to generate infected ticks and allows introduction of defined quantities of spirochetes, including mutant isolates that are attenuated for infection in mice and thus cannot be naturally acquired by ticks. We also describe a quantitative PCR-based protocol for the measurement of B. burgdorferi in tick and murine hosts targeting spirochete RNA that is highly efficient, reproducible, and a better surrogate of active infection.
Key wordsTick artificial infection microinjection B. burgdorferi burden Quantitative PCR
We sincerely thank our collaborators and members of our laboratory, in particular, Frank Yang, Manish Kumar, Adam Coleman, John Anderson, Toru Kariu, Brian Backstedt, for their assistance with developing the protocols presented in this chapter. This work was supported by funding from University of Maryland, College Park as well as grants from the National Institute of Allergy and Infectious Diseases, Award Numbers AI080615, AI106059 and AI116620 to UP.
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