Whodunit? Probably not Bartonella

Whodunit? Probably not Bartonella
by Paul Basilio of Vetlearn.com

If a differential diagnosis were a murder mystery novel, Bartonella would be the butler. Everyone may assume it is responsible for the problem, but the real culprit is most likely something more complicated.

In recent years,
Bartonella has become a popular answer to many diagnostic questions in cats, despite research that shows that the bacteria is part of a cat’s normal flora and does not play a major role in most disease processes.

In 2006, a group of experts published an American Association of Feline Practitioners (AAFP) panel report that acknowledged the prevalence of the bacterium but, based on peer-reviewed research, could not name it as a cause of much disease in cats.

The report stated that while prevalence rates can vary, studies have shown that Bartonella henselae and clarridgeiae organisms are present in about 20% of cats. In one study, antibodies against Bartonella have been shown to be present in as many as 93% of feral cats, but the seroprevalence rate of a population of cats will generally be twice the bacteremia rate.

Cats typically contract Bartonella from infected fleas and flea feces, but Bartonella DNA has been found in ticks, biting flies and other blood-feeding parasites. It is also potentially transmitted amongst cats by biting and scratching. The bacteria are not transmitted through gestation, by milk or from infected cats during breeding.

Still, the threat that Bartonella presents to cats is much lower than some anecdotal evidence would suggest. The AAFP panel states that more research will be necessary to conclude that Bartonella is a cause of disease because most cats with Bartonella organisms show no signs of illness.

The panel’s findings jibe with what Arnold Plotnick, DVM, DACVIM, DABVP, a feline specialist in New York City, sees in his patients. “I think that people jump to Bartonella infection as the answer to a lot of questions without it being an accurate answer,” he says. “Two things can exist in a cat simultaneously, but it doesn’t mean that one is the cause of the other. A cat can have gingivitis and test positive for Bartonella, but that doesn’t mean the Bartonella is causing the gingivitis.”

In fact, anecdotal evidence linking Bartonella to stomatitis, but experts agree that correlation is not causation, and appropriately controlled peer-reviewed evidence has shown no statistically significant difference between the Bartonella antibody titers or the positive PCR assays of cats with stomatitis and cats without.