RALEIGH, N.C. — The bacteria Bartonella vinsonii subsp. berkhoffii and Bartonella henselae, normally transmitted by fleas and/or ticks, may be transferred to human babies via the mother, increasing the risk of chronic infection and bacterially triggered birth defects, according to research published in the June 2010 Journal of Clinical Microbiology. But this is just one of a number of emerging findings impacting humans and animals alike, one expert notes.

Edward B. Breitschwerdt, DVM, Dipl. ACVIM, professor of internal medicine at North Carolina State University and an internationally recognized expert on the Bartonella genus, was lead author of this and other similar case studies. Bartonella species, sustained in nature through ticks, fleas and other insects that bite, also can be passed through infected dogs and cats.

"One of the more important messages behind this research is that Bartonella is a new and emerging bacterial pathogen," Breitschwerdt says. "As a result, there is an increasing amount of information that is being generated and published that most veterinarians are not going to be readily familiar with. Much of the material is being published in microbiology, parasitology and vector journals, not in the veterinary literature."

1. Bartonella species have been identified in the blood of numerous animal species. Historically, 10 to 15 years ago, researchers were not aware that these bacteria were in the blood of healthy animals and in animal patients.

2. "What complicates matters is that there are a very large number of proven and perhaps even larger number of suspected arthropod vectors that may be responsible for transmission in nature," Breitschwerdt notes.

For instance, the gray squirrel has one type of Bartonella species that it carries in its blood, and the groundhog has yet another Bartonella species, and so on.

A common Bartonella species-associated illness is cat-scratch disease, triggered by B. henselae, which can be active in a cat's blood for years. Previously, the disease was thought to be a one-time infection, but Breitschwerdt's work has disproven that, showing cases of adults and children with chronic, blood-borne Bartonella species infections.

Through Bartonella species-research, Breitschwerdt and colleagues have discovered that reservoir-adapted animals can carry the bacterial organisms in their blood without carrying obvious signs of disease. Using the cat as an example, the flea would be responsible for being its transmission source.

"The cat and flea are happy with each other and in a so-called state of peace for the most part. But when the same Bartonella species ends up in a horse, these animals are not reservoir-adapted, and the same is true for dogs and humans, all of which may be then exposed to disease," he explains.

In the current case study, which occurred over several years, Breitschwerdt's research team analyzed tissue and blood samples from a mother, father and son who had chronic illnesses for 10-plus years. An autopsy of the son's twin sister who died soon after birth revealed DNA proof of B. henselae and B. vinsonii subsp. berkhoffii bacteria also present in the other family members.

The parents had ongoing neurologic conditions, such as headaches and memory loss, along with muscle weakness, difficulty breathing and fatigue before the children's births. Their son had chronic illnesses since birth. Microbiologic test results showed the parents were exposed to Bartonella species before the twins' births. Because the bacteria was found in both twins, there is the possibility, according to researchers, that the children were infected during the mother's pregnancy.

Funding, not findings, lacking

Given the abundance of findings related to Bartonella species organisms to date, Breitschwerdt hopes the funding catches up to the study results.

"What I've learned is that it takes a lot of time and work by a number of research groups before any emerging bacteria is appreciated for its importance," he says. "With the exception of one NIH-funded Bartonella study that I'm aware of, there is no federally funded work going on relative to the importance of this bacteria as a cause of disease. It is virtually impossible to get federal funding.

"We are doing research relative to human illness and telling human colleagues, 'Hey folks, there's a problem out there,'" he adds. "We've done this with limited resources in terms of funding, equipment, time and space. I don't understand why there is not more attention being paid to this newly discovered species of bacteria. Yet as we understand it, it will never cause a huge outbreak of cases in relation to the flu epidemic."

Yet, he says, it has the potential to cause chronic, very insidious illness.

"Any of these organisms are capable of causing complex disease presentations, which are difficult to nail down on basis of evidence-based medicine," he says.