Bartonella is receiving a good deal of attention but it’s not a recently discovered bacteria?
There are reports from the 1850s of Indians in the Peruvian mountains having lesions that we now know were caused by these bacteria. The genus is named after Alberto Leonardo Barton Thompson, a Peruvian scientist who announced his findings in 1905 after studying an outbreak of illness among workers who built the Oroya-Lima railway through Peru’s mountains. The workers were bitten by sand fleas that transmitted a bacteria now known as Bartonella bacilliformis and tens of thousands died. Another large outbreak occurred among soldiers in World War I who obtained a related bacteria (Bartonella quintana) through body louse bites. The issue went under the radar again but it’s an opportunistic pathogen that causes problems for humans during periods of famine, warfare, or perhaps when an individual’s immune system is compromised. The HIV epidemic resulted in the discovery that B. quintana and a “new” bacteria, Bartonella henselae could cause unusual vasoproliferative lesions in immunocompromised individuals. We have known about cat scratch fever since the 1950s, however, it wasn’t until1992 when a researcher with the Centers for Disease Control and Prevention made a connection between pathogens (B. henselae) in the blood of HIV patients and bacteria in the lymph nodes of patients with cat scratch disease.
What is different now?
We are finding many different species of Bartonella in a surprising number of animal hosts. At one time the accepted thinking was that Bartonella did not exist in North America. This assumption was clearly wrong. Current evidence suggests that this pathogen appears to be extremely successful in evolving and thriving in insects and in a spectrum of mammalian hosts. What is of major interest is that our research indicates that this pathogen can produce persistent infection in immunocompetent people—healthy individuals—and ultimately make them ill. So it’s not just the immunocomprised people, like HIV patients, or transplantation recipients that are at risk.
How is it that a veterinary research team discovers a disease process that is being called a “Silent Epidemic” among humans?
It’s an important aspect of what is being called “One Medicine.” As veterinarians, we take an oath to use our knowledge and skills to benefit society and protect the health of all animal species—humans included. The promotion of public health and the advancement of medical knowledge is part of our mandate. On a practical basis, veterinary researchers track disease processes across all species and we are in the best position to diagnose infectious animal to human diseases and identify disease patterns. Related to this specific emerging infection, my laboratory has developed and North Carolina State University has patented a testing process that allows us to use an insect cell culture medium to grow and characterize Bartonella species from samples of infected animals or humans. This was not possible before we developed this novel diagnostic approach. The medical community could not treat what it didn’t realize existed since the pathogen does not show up on standard medical tests. Our findings are being duplicated by other researchers in Germany and at the Centers for Disease Control and Prevention, so we are confident that this is a major development in the detection and treatment of patients infected with Bartonella.
So is every person who comes in contact with an animal at risk?
No. Being licked by a puppy or bitten by a tick does not mean that you will automatically become ill with a Bartonella strain. In medical terms, transmission is most likely not very efficient, but there is still a lot we do not know about this medically important area. One simple step for preventing the transmission of the pathogen is keeping fleas and ticks off pets. The products currently on the market are safe and effective at doing this. Reducing your exposure to ticks is also important—as it always has been because of the transmission of other tick pathogens. It’s also important to note that antibiotic therapy can treat the bacteria in both animals and humans.
What would you like to see as an outcome from this research?
More Bartonella research and more funding for that research in both human and veterinary medicine. We have ongoing collaborations with the Centers for Disease Control and Prevention, Duke University Medical Center, the Eberhard-Karls-Universitat, Tubingen Germany and the University of Bari, Italy. We believe these investigations could have a positive impact on the health of humans and animals and lead to the elimination of what may be a silent and unrecognized epidemic among humans. Unfortunately, very little research funding is currently devoted to Bartonella by national and international funding organizations. This I would clearly like to see change. I give presentations at numerous international seminars attended by medical doctors, veterinary researchers, public health officials, and government leaders. We need to work together to protect public health and to promote “One Medicine.” To do this in any effective manner, there must be a substantial increase in the support of the veterinary medical infrastructure in the United States and throughout the world.
November 21, 2008