Until recently, bartonella infection was thought to be an exclusively feline condition. However, research has now shown that dogs who come into contact with cattle or ticks can also pick up this disease.
Whether the infected animal is a cat or a dog, the signs are vague, such as fever and lack of energy — and then, after a few days, the pet recovers without treatment.
None of this would matter very much if it weren’t for the fact that humans can accidentally pick up the infection and make those with weak immune systems ill.
The typical, recently infected cat may act off-color, run a fever and walk stiffly, as if her joints hurt. This phase lasts only 2 or 3 days, and then she gets better on her own accord.
Although these cats are not ill, traces of bartonella can be found in their blood — and in rare cases, it lodges in their liver, kidney or heart, where it causes damage in later life.
The significance of bartonella lies in the link between asymptomatic cats and “cat scratch fever” people. This is usually a mild, self-limiting illness, the exception being people with weak immune systems such as the very young or old, HIV-positive people, and those on chemotherapy.
The signs of cat scratch fever in humans start a week to several months after exposure and include fever and enlarged lymph nodes. If you are in an at-risk group and worried about cat scratch fever, seek medical advice immediately.
Bartonella is a bacterium that infects its host’s red blood cells. The bacteria are transferred from animal to animal by insects such as fleas, ticks and certain biting flies.
Bartonella can infect many species, including mice, rats and rabbits. This means that feral cats with fleas who live near mice and rats are much more likely to catch bartonella than a well-fed house cat in the same neighborhood.
Historically, it was thought that humans picked this infection up from cat scratches. This now seems less likely, as early research suggests a biting insect is necessary for cat-to-human infection.
The video below features Roxy, a kitten who tested positive for bartonella and was treated with antibiotics:
The most reliable method of diagnosis is culturing bartonella from the blood or body tissue of the suspected case.
There is a blood test that checks the body’s immune response to bartonella, but this test has limitations in that it can’t show the difference between a cat with immunity to bartonella and a cat with an active infection.
In the same way that we recover from a cold, cats and dogs with healthy immune systems recover from bartonella without treatment.
The infection is treatable with a variety of common antibiotics, but some experts argue that the infection must be treated only if the cat lives with someone who has a weak immune system.
Because animals most likely to pick up bartonella are those with fleas or ticks, it’s sensible to use regular parasite control to reduce the risk of flea and tick bites.
This is a “lifestyle” infection in that feral cats who hunt vermin or dogs living in rural areas in contact with cattle or deer are more at risk than house cats with good parasite control.
- Clinical Medicine in the Dog and Cat. Michael Schaer. Publ: Manson Publishing.
This pet health content was written by a veterinarian, Dr. Pippa Elliott, BVMS, MRCVS. It was last reviewed Dec. 18, 2014.