Dr. Kyle Warren:

Bartonella is maybe the most mysterious of what people call the Lyme co-infections, and it's probably the most mysterious because it's also more than a co-infection.

Bartonella can be a co-infection with Lyme but also a stand-alone infection.

Bartonella actually gets into the veterinary world because it's carried by mammals; it's classically known as cat scratch fever, so cats are known to be the reservoir. And so, basically, it can be transmitted by flea, by lice from cats, and then to humans. Now while that's the famous way it's transmitted, we also know almost all mammals can be carriers. We've even found it in about 10% of dogs, it's about 30-40% of cats are the estimates. But we have found it in whales, so we know Bartonella is easier to move around than some of the other tick-borne illnesses.


What is its correlation with chronic Lyme?

Bartonella can cause all the same symptoms as Lyme. So, it can cause fatigue, joint pain, rashes, and neurological symptoms, just like Lyme can, which is where you get some confusion about, is this Lyme, is it Bartonella, is it both? If you have a cat and you have symptoms that are very similar to Lyme, you really need to look at Bartonella. It can come from your dog too, just want to phrase that. A little lower chance, but if you have a cat or dog consider Bartonella if you're having that mysterious chronic fatigue, rashes, pain, neurological problems, really can come from just fleas from an infected animal. And your animal may be healthy; they may be just a carrier. 

How common is Bartonella in humans? 

Bartonella is a disease we learned a lot about, if you look back in history, people came down with HIV. And as people come down with HIV, they become immune suppressed. And all of a sudden, these bugs that have probably been around for a long time become more obvious because in immune suppressed people, these bugs cause major problems. And this is also where, if I were to, kind of, classify the arguments for Bartonella, it gets even more muddy than Lyme disease. There are some people who think that about 25% of all mammals have Bartonella, including humans. That would mean there's about 80 million Americans who have Bartonella, now most of these are asymptomatic. And really, when I look at symptomatic, there's somewhere between maybe a million, maybe two million people infected with Bartonella. Now CDC rates of cat scratch fever are much, much lower than that, but that term is being abandoned for Bartonellosis, which is a little more encompassing than just a simple cat scratch fever.

So, if you have mysterious symptoms, especially like seronegative reactive arthritis, where you're just, you're not feeling right, something's wrong and you don't know, start with testing. Lyme disease is a good place to start, but we always run a Lyme and co-infection panel including Bartonella. The one to test is Bartonella Henselae; that's the place to start.