A Surprising Discovery
In 2019, researchers at NC State University’s Vector-Borne Disease Lab made an unexpected find: a previously unknown species of Rickettsia detected in a dog’s blood. Rickettsia is part of the bacterial group that causes spotted fever diseases, including Rocky Mountain Spotted Fever, one of the most serious tick-borne illnesses in the United States.
“When we identify a new organism, we immediately contact the veterinarian who sent us the sample to learn more about the dog’s condition,” explained Dr. Barbara Qurollo, lead investigator on the project. Soon, multiple dogs were reported sick with fever and dangerously low platelets, putting them at risk for bleeding and echoing Rocky Mountain Spotted Fever.
Until this point, only one Rickettsia species was thought to cause this illness in dogs. The findings suggested that dogs were facing a new, previously unidentified infection.
Digging Deeper with CHF Support
With funding from the AKC Canine Health Foundation (CHF), Dr. Qurollo launched a study titled “Enhanced Detection and Characterization of Spotted Fever Group Rickettsia Species in Dogs and Ticks with Focus on a Novel Rickettsia Species Infecting Clinically Ill Dogs in the U.S.”
The study set out to do two things: first, to learn more about the newly discovered Rickettsia bacteria, and second, to create better tests to tell different Rickettsia infections apart.
These bacteria are incredibly challenging to isolate, as they hide inside the cells lining blood vessels, which makes them very difficult to detect in blood samples.
To increase their chances of finding the bacteria, her team expanded the search to nearly 2,000 ticks, using methods called “dragging” and “CO₂ trapping.” While the elusive target species remained hidden, the team did discover another strain, Rickettsia oklahomensis, and successfully sequenced its genome.
This important step led to the development of two new diagnostic tests, one capable of distinguishing between four Rickettsia species in clinical samples.
Breakthrough in the Lab
The research team suspected that the mystery organism was carried by the lone star tick — the same species associated with red meat allergy in humans. Despite repeated searches, they could not confirm it.
Then came a breakthrough. Using a new culture method described by the Centers for Disease Control and Prevention (CDC), the NC State team was able to successfully grow the bacteria. With one sample containing high levels of the pathogen, the researchers finally cultured the hard-to-find new organism in canine white blood cells and cells lining blood vessels.
The team quickly sequenced the whole genome, captured images, and documented cases from 17 sick dogs. A publication is now under review describing the organism, its genetic code, and its impact on canine health.
“This is our strongest evidence yet that this is a true pathogen in dogs,” said Dr. Qurollo.
Why This Research Matters
Tick-borne diseases are a growing concern for both people and pets. Better diagnostics and deeper understanding of emerging strains can mean faster treatment for sick dogs and more effective prevention.
“There is…funding for diseases that affect humans, especially zoonotic ones,” said Dr. Qurollo. “But diseases that affect dogs alone are much harder to study. That is why support from CHF is so vital.”
Thanks to donor generosity, CHF-funded research is uncovering pathogens before they spread further, protecting the health of dogs everywhere.
