top of page

Uncovering the Link Between Bartonella and Hemangiosarcoma: Part Two

a dog with black mane and brown paws lays down on a wooden bridge

This is part 2 of the article. To read part 1, please follow this link

Hemangiosarcoma (HSA) is a highly metastatic endothelial cell tumor that constitutes 5% of all malignancies in dogs. That equates to about 10,000 dogs per year in the United States. It is also responsible for two-thirds of canine cardiac and splenic neoplasms overall.

Dr.Breitschwerdt and his team performed three studies around Bartonella and HSA, with the first finding the bacteria in a much higher prevalence in the spleen. About 50% of HSA cancer cases occur in the spleen, an organ responsible for eliminating pathogens - such as Bartonella - from the circulatory system. “Persistent infection or inflammation caused by Bartonella may increase the risk for hemangiosarcoma later in life,” Dr. Breitschwerdt says.

The team used PCR testing posteriorly confirmed by DNA sequencing to study fresh frozen HSA tissue, fresh frozen non-tumor tissue, and whole blood and serum from 110 dogs representing 39 breeds and mixed breeds. They found that 73% of all tissue samples from these dogs were positive for Bartonella DNA. The presence of Bartonella DNA in 57% of cardiac HSA tumors and 93% of non-tumor cardiac tissue makes it interestingly higher in the proportion of positive samples overall compared to splenic tissues.

The good news is that dogs diagnosed early with bartonellosis and treated with a combination of antibiotics typically fully recover from it. Still, diagnosing Bartonellosis is challenging, as there is no diagnostic gold standard for Bartonella infection in dogs. “It relies on a combination of culture, blood, and molecular tests with poor, variable, or undetermined sensitivity.” Dr. Breitschwerdt furthens.

The suggestion that an infection could be a root cause of cancer proposes that early diagnosis and treatment might prevent or resolve the cancerous state. One of the primary focuses in the research has been to try to enhance the diagnosis and certainly the antemortem diagnosis of Bartonella in dogs with hemangiosarcoma.

The research is part of a five-year study funded by the Cohen Foundation and the AKC Canine Health Foundation through its Hemangiosarcoma Research Initiative, which has invested over $4.8 million in 33 grants since 1995.

He believes that their research may be transformative to the way we approach caring for dogs with this type of cancer in the future. He believes that we have an opportunity to document the first bacteria in medicine and veterinary medicine that actually causes a tumor in the dog and to develop a vaccine that will decrease the prevalence of this tumor.

Future studies should compare the ability to screen dogs with HSA for Bartonella infection to assess the potential role of Bartonella as a cause or cofactor in HSA.

"However, if you ask me what I believe, I believe that Bartonella clearly is a cause of hemangiosarcomas. And I believe that if we can create a vaccine, which is also work that's, in part, being supported by the AKC Canine Health Foundation in our laboratory, we may be able to potentially prevent a devastating cancer in man’s best friend." Dr. Breitschwerdt stated: "we might be able to keep veterinary surgeons from cutting these dogs with a ruptured spleen and belly full of blood in the middle of the night."

To learn more about Bartonellosis you can watch Dr. Breitschwerdt's informative video here.


bottom of page