Q fever is caused by the bacterium Coxiella burnetii, which is a big problem in cattle, causing infertility and abortion, and is of real concern because people can catch it.
Occasionally a cat or dog becomes infected, but they rarely become ill. Pregnant animals are most at risk because Coxiella causes abortions, stillbirths or weak newborn puppies or kittens.
Humans who come into contact with aborted puppies and kittens as well as veterinarians helping under such circumstances are at risk. They should wear gloves and a mask to avoid accidental infection. It is thought that Q fever in people can cause pneumonia, and there may be a link between Coxiella and chronic fatigue syndrome.
Not much is known about Q fever in pets. Animals experimentally infected with Coxiella show a brief loss of appetite, lack of energy and enlarged spleens.
However, these symptoms settle down of their own accord without the need for treatment. The only consequences are seen in pregnant females where it may terminate pregnancy or cause puppies or kittens to be dangerously weak at birth.
Q fever is primarily a cattle infection and accidentally infects a small number of pets.
It is spread by aerosol. Those most likely to pick up infection are pets living in rural settings with regular contact with cattle, sheep or goats. Intermediate hosts act as a go-between among ruminants and the pet, including woodland animals, birds, and insects, may spread the bacteria — although the exact mechanism of transfer is not clear.
Coxiella is spread in droplet form and can survive in a dormant form for long periods of time despite the use of disinfectants.
In cattle, sheep and goats, a diagnosis is made by smearing the placenta from a stillborn animal onto a microscope slide, which is then stained and examined to see if Coxiella is present.
The ideal test for pet animals has not yet been developed. The organism can be cultured, but it requires samples to be taken from the deceased offspring; it is of no use to screen pregnant animals.
In theory, blood tests looking for antibodies for Coxiella exist, but the significance of the results has not been investigated. Another option is the PCR test, which can detect the presence of Coxiella DNA in an animal, but again, the usefulness of this has not been established.
People are treated with antibiotics from the oxytetracycline family. It seems likely this is also the best antibiotic for animals, but because so few cats and dogs show symptoms, this logic has not been tested.
It is best not to breed from a female dog who has had previous unsuccessful pregnancies and was subsequently diagnosed as having Coxiella.
Pets should not be allowed access to stillborn animals or their placentas.
Indeed, there is a higher incidence of Q fever in animals living in a rural setting, so if a female is required for breeding purposes, it seems sensible to limit her access to farm animals to reduce the risk of infection.
- “Is Q fever an emerging or re-emerging zoonosis?” Arricau-Bouvery & Rodolski. Vet Rec, 36(3): 327–349.
- “A dog-related outbreak of Q fever.” Buhariwalla, Cann & Marrie. Clin Infect Dis, 23(4): 753–755.
This pet health content was written by a veterinarian.