Image created by Dr. Michael J. Miller
A breakthrough at the University of Missouri transforms how Rocky Mountain spotted fever is diagnosed. The new method detects the deadly tick-borne disease in just 40 minutes — a leap that could help patients get lifesaving treatment sooner.
Early diagnosis of Rocky Mountain spotted fever is critical. Patients can go from a tick bite to a severe fever, headache and rash within days. Yet existing diagnostic tools can be expensive, hard to access or unable to detect small amounts of the bacteria in a blood sample.
Mizzou’s new method changes that, delivering clearer answers when they matter most.
The test, which involves mixing DNA from a sample with specialized reagents in two quick, 20-minute steps, can be completed at room temperature without the need for complex and costly laboratory equipment. After 40 minutes, a change in liquid color indicates a positive detection of the bacteria.
The antibiotic doxycycline is used to treat the disease, and clinicians often prescribe it while waiting on confirmatory testing. Right now, that can take too long.
“Unfortunately, this disease can be particularly deadly in children if diagnosis is delayed, and often patients may not realize they have been bitten by a tick until they feel extremely ill,” Roman Ganta, a Curators’ Distinguished Professor in the College of Veterinary Medicine and investigator in the Bond Life Sciences Center, said. “Quicker diagnosis leads to quicker treatment with doxycycline, so we are hopeful our research can improve outcomes for those impacted.”
Ganta hopes this test will eventually be used in rural or under-resourced clinics around the world where the advanced laboratory equipment currently needed to detect Rocky Mountain spotted fever is inaccessible. He is in discussions with the Veterinary Medical Diagnostic Laboratory at Mizzou to see whether this test may be utilized in clinical applications in the future.
“By making this test more accessible, more patients can benefit from our work one day,” Ganta said.
The study, “A rapid isothermal RPA–CRISPR/Cas12a assay for detection of Rickettsia rickettsii,” was published in Frontiers in Microbiology.
Reference
Ozubek S, Liu H and Ganta RR (2026) A rapid isothermal RPA–CRISPR/Cas12a assay for detection of Rickettsia rickettsii. Front. Microbiol. 17:1823193. doi: 10.3389/fmicb.2026.1823193
Abstract
Introduction: Rocky Mountain spotted fever (RMSF) resulting from the tick-borne Rickettsia rickettsii infections is a potentially fatal tick-borne disease affecting humans and dogs in the Americas. It is difficult to confirm the diagnosis early in the laboratory on account of low-level and inconsistent rickettsemia in whole blood.
Methods: Here we established a fast, fully isothermal RPA–CRISPR/Cas12a assay that targeted the vitamin uptake transporter (vut) gene of R. rickettsii. Two independent crRNA primer sets (104 bp and 92 bp) were developed to independently amplify the gene target to enhance the reliability and specificity of the assay.
Results: Using quantified synthetic DNA (gBlock) standards derived from the R. rickettsii Sheila Smith vut target region, the assay was able to detect target DNA in about 40 min at 37 °C with an observed analytical detection limit of 60–70 copies per reaction. Specificity testing on four R. rickettsii strains and a panel of non-target spotted fever group rickettsiae and tick-borne bacteria of clinical importance demonstrated no cross-reactivity of the assay with these pathogen nucleic acids. Applied to archived longitudinal canine whole-blood DNA extracts from experimentally infected dogs (n = 6), the performance was intermittent for known limitations of whole blood testing in RMSF and limited to specific post-infection days.
Discussion: The findings of this study support the feasibility of RPA–Cas12a as a rapid molecular workflow for R. rickettsii detection, while indicating that broader validation in additional clinically relevant and removed tick sample types is still needed.