Bartonellosis, sometimes called cat scratch fever, is a bacterial infection that can affect dogs as well as cats and humans. Although rare in dogs, bartonellosis can be acquired from external parasites like fleas, ticks, and lice (not from cat scratches, as the common name implies). This infection can cause an array of symptoms, including vomiting, skin redness, swollen lymph nodes, eye inflammation, fever, and irregular heartbeat.
The first line of treatment is antibiotic therapy, but due to the complexity of the infection, additional medications may be needed to treat affected organs. Bartonellosis is rarely fatal in dogs, but early treatment is crucial—especially when the heart is compromised.
What Is Bartonellosis?
Bartonellosis is an infection caused by one of many species of bacteria in the genus Bartonella. These bacteria are transmitted into a dog's bloodstream by external parasites. While rare in dogs, bartonellosis infection may cause a variety of symptoms or no symptoms at all.
Symptoms of Bartonellosis in Dogs
Not all dogs will become sick when infected with Bartonella bacteria. However, dogs are more likely than cats to develop symptoms if they do contract the infection. The clinical signs of bartonellosis in dogs are myriad, and more may exist that veterinarians have not yet identified. In effect, the disease can cause different effects in different dogs—many of which are present in other illnesses—making bartonellosis a diagnostic challenge, especially due to its relative rarity in dogs.
The following symptoms have been associated with bartonellosis in dogs:
One of the more serious complications of bartonellosis is endocarditis (inflammation of the lining of the heart) indicated by the presence of an irregular heartbeat, which is more likely to be detected by a veterinarian than the owner.
Lymph node swelling is associated with bartonellosis, but it is also a common symptom of many other infectious illnesses, as are the rest of the symptoms on the above list.
To make diagnosing this illness even more challenging, these symptoms are all potentially indicative of other parasite-borne infections, such as Lyme disease and ehrlichiosis, which may be present concurrently with bartonellosis.
Causes of Bartonellosis
Theoretically, a dog could contract bartonellosis from an infected cat's scratch or bite, but dogs usually become infected with Bartonella bacteria after being bitten by ticks or fleas that carry these pathogens. There are many strains of Bartonella bacteria, but the ones associated with illness in dogs include:
- B. vinsonii subsp. berkhoffii (most common)
- B. henselae (more common in cats and humans; causes "cat scratch fever")
- B. clarridgeiae
- B. elizabethae
Diagnosing Bartonellosis in Dogs
If your dog shows signs that may be associated with bartonellosis (or any other illness), it is important to go to your veterinarian since early diagnosis and treatment may prevent the illness from progressing.
After completing a physical examination, your vet will recommend lab tests to determine the cause of your dog's illness. At the very least, these tests will include a complete blood count to assess your dog's immune response and a blood chemistry panel to assess organ health and metabolic function.
If your vet suspects bartonellosis, a blood culture and other diagnostic procedures will be needed to help identify the pathogen(s).
Antibiotic therapy is the main treatment for bartonellosis in dogs. Treatment protocols vary depending on many factors. Your dog will most likely need to take several different types of antibiotics for weeks to months. If your dog has developed any secondary conditions, your vet might recommend other treatments to address them.
If your dog has a serious secondary problem or is not responding to treatments, your vet may refer you to a veterinary specialist for advanced diagnostics and/or treatments.
Prognosis for Dogs with Bartonellosis
Bartonellosis is not usually fatal in dogs, but its severity varies from dog to dog. The secondary issues caused by the infection can lead to death, particularly in cases that involve heart damage. Early diagnosis and treatment are key to your dog's survival.
How to Prevent Bartonellosis
The best way to prevent bartonellosis in your dog is to use effective flea prevention and tick prevention year-round. Check your dog for signs of fleas and ticks regularly. Talk to your veterinarian about safe and effective parasite prevention for your dog.
Is Bartonellosis Contagious to Humans?
To date, it is unproven that humans can contract bartonellosis from dogs, and it is considered a very low likelihood that this mode of transmission occurs. The bartonellosis infection that humans contract (cat scratch fever) involves B. henselae bacteria present in cats' bodies that are transmitted through bite or scratch wounds.
Of course, it's important to seek medical attention if you get a dog bite or a serious scratch.
Álvarez-Fernández A, Breitschwerdt EB, Solano-Gallego L. Bartonella infections in cats and dogs including zoonotic aspects. Parasites & Vectors. 2018;11(1):624.
Understanding Bartonella--Risk Factors, Diagnosis and Management. World Small Animals Veterinary Association.
Canine Bartonellosis. Peoria Area Veterinary Group.