Bacterial Zoonotic Disease in Dogs
The Q fever disease is caused by the Coxiella burnetii, a pathogenic bacteria that is structurally similar to the Rickettsia bacteria but genetically different.
A dogwill most commonly become infected with the organism if it ingests infected bodily fluids (i.e., urine, feces, milk, discharges), tissues, or diseased carcasses (e.g., those from cattle, sheep, or goats). The bacteria can also become airborne and is transmittable through fleas or lice, which carry C. burnetii in its parasitic form.
Q fever is an worldwide endemic, affecting cats and dogs of any age, gender, or breed, and as a zoonotic disease, it is transmissible to humans. Care must be taken when dealing with bodily fluids, organs, and/or tissue material of any animal, particularly farm animals. Dispose of all birth remains properly and feed your dog pasteurized products only.
If you would like to learn more about how this disease affects cats, please visit this page in petMD health library.
Symptoms and Types
Lungs are thought to be the main portal of entry into systemic circulation. C. burnetii will then replicate in the organ's lining, causing widespread vasculitis. Inflammation of the dog's blood vessels will result in the death of its blood cells and hemorrhaging of the lungs, liver, and central nervous system.
Once the dog has contracted the disease it may display some of the following symptoms:
- Fever
- Lethargy
- Anorexia
- Depression
- Incoordination
- Seizures
- Miscarriage (not common in dogs)
The types of symptoms your dog displays and the severity of the Q fever will ultimately depend on the particular strain of organism your dog is infected with. Often, animals with C. burnetii will undergo a period of latency (inactivity). However, during the birthing process the bacterium may reactivate, resulting in large numbers of bacteria entering the placenta, and the host's bodily fluids, urine, feces, and milk.
Causes
Exposure to animals infected with C. burnetii (especially those that have just given birth), ticks, fleas, and lice.
Diagnosis
Providing a detailed history of your dog's health and its lifestyle leading up to the onset of the symptoms will assist your veterinarian in the diagnosis.
Your veterinarian will then conduct a complete blood profile on your dog, including a chemical blood profile, a complete blood count, and a urinalysis. Once collected, the dog's blood serum will be refrigerated to assist in the identification of the organism's type. The veterinarian will also collect a tissue sample (e.g., from the placenta) and refrigerate it for later use as an inoculator.
Treatment
There are medications that are effective in eliminating the bacterial infection, and your veterinarian will guide you in creating an effective treatment plan for the dog. However, be aware that C. burnetii is more resistant to eradication than other types of Rickettsiae, a similar type of bacteria.
Because of the zoonosis of Q fever, take extreme care when handling infected animals. To lessen the risk of transmitting the disease, your dog should be immediately hospitalized once it is found to have Q fever.
Living and Management
It can be difficult to determine the success of therapy because many animals will spontaneously improve. However, even asymptomatic cases should be aggressively treated because of the potential for human infection.
By the time a diagnosis is made in a dog, human exposure and infection have more than likely occurred. Therefore, anyone who has been in contact with the dog should also seek immediate medical attention. The incubation period from the time of contact until the first signs of illness is 5 to 32 days.
Humans typically contract the disease by inhaling infected aerosols (i.e., airborne material), especially after an animal has given birth; children are commonly infected from ingesting raw dairy milk, but are usually asymptomatic. Person-to-person transmission is possible but rare.