"In my opinion, bartonella may prove to be the most important emerging infectious disease of the next decade," said Dr. Ed Breitschwerdt, DVM, a specialist in internal medicine and infectious disease at North Carolina State University.
Bartonella is an infection linked to heart valve disease and may have a role in neurologic and arthritic disease. Still, few people even know what it is.
Essentially, it's the bacteria that causes cat scratch disease. But experts say most any animal with claws tainted by flea feces can transmit it, which makes treatment tough.
"The organism changes its nature, its outer surface, again, so that the immune system cannot eliminate it," said Dr. Breitschwerdt.
Forty percent of cats carry bartonella at some point. With 24,000 annual cat scratch cases, up to 90 percent of those affected will see a rash, nausea and weight loss. Less than 20 percent could see sensory loss, pneumonia or encephalitis.
"Understanding transmission is of critical, critical importance," said Dr. Breitschwerdt.
While bartonella can circulate in the blood of cats and dogs, it can cause tumor-like lesions in people. It's tough to detect because it stays in human blood in very low levels.
"I think in the context of Bartonella, there's many, many more questions right now than answers," said Dr. Breitschwerdt.
With research now including sick dolphins and whales, he says you need to be concerned now.
Bartonella can cause sudden death in a very small number of cases. Diagnosis can be confirmed with a specialized blood culture approach. Still, only a few antibiotics successfully treat the disease.