Q fever, also known as coxiellosis, is a disease caused by the bacterium Coxiella burnetii. The infection can lead to abortions in certain animal species and may cause mild to severe illness in humans.
Animals most likely to contract Q fever include goats, sheep, and cattle. Other animals such as cats, dogs, rabbits, horses, pigs, rodents, and some birds are less commonly affected but remain susceptible. Humans are also at risk of infection.
Animals typically acquire Q fever through ingesting or inhaling bacteria from body fluids or secretions of infected animals—such as milk, urine, feces, or birthing products. The bacteria can persist in the environment for extended periods and spread via contaminated dust particles. Ticks may transmit the bacteria between animals; however, this form of transmission is more frequent among wild animals.
Transmission to humans often occurs when individuals inhale contaminated dust or come into contact with animal birth products. Consuming unpasteurized milk is another possible source of infection.
The main clinical sign of Q fever in animals is late-term abortion or stillbirths within herds—a phenomenon sometimes referred to as an abortion storm. Veterinary investigation is advised if there is an increase in reproductive issues among livestock. It should be noted that some animals may be infected without displaying any symptoms. Effective management practices are important for limiting disease spread.
Biosecurity measures are recommended to prevent Q fever transmission:
– Isolate aborting and parturient animals indoors to reduce airborne dissemination of bacteria.
– Dispose of placentas and aborted fetuses by burning, burying, or sealing them in leak-proof containers.
– Compost contaminated bedding and manure for at least 90 days before spreading; apply manure only on non-windy days away from residential areas.
– Pasteurize milk products to eliminate potential bacterial contamination.
– Individuals handling suspected cases should use personal protective equipment including masks (preferably N95 respirators), gloves, rubber boots, and protective clothing.
Regarding treatment in animals: “Based upon current data, antibiotic usage in the absence of ongoing abortions in livestock is not warranted. If your herd or flock is diagnosed with Q-fever your veterinarian and Oregon Department of Agriculture (ODA) veterinarians will help develop a management plan to reduce spread to animals and humans.”
Human infections are often short-lived and resolve without medical intervention. Symptoms can include fever, chills, fatigue, muscle pain (myalgia), and headache. In some instances the illness may progress to pneumonia or affect organs such as the liver or heart; rare chronic cases can develop months or years after initial infection requiring prolonged antibiotic therapy. Livestock owners concerned about their health should consult their healthcare provider if they experience symptoms consistent with Q fever.
The Oregon Department of Agriculture encourages anyone suspecting signs of Q fever in their herd or flock to contact a veterinarian for testing.
For additional information about Coxiella burnetii infection (Q fever), animal owners can reach out to the ODA Animal Health Program at 503-986-4680.
