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Could a Bacteria Be The Cause of Hemangiosarcoma? (Pt.1)

a border collie sits attentive over crunchy leaves in a forest

The enigmatic roots of hemangiosarcoma continue to elude even the most rigorous research. Yet, efforts persist to shed light on any theory that could finally uncover its secrets. One of the most compelling theories encircles a very discreet bacteria.   

Edward B. Breitschwerdt, DVM, DACVIM, and part of a multidisciplinary Bartonella Research Consortium spoke to VetVine about his work studying this bacteria for over 20 years, intertwining human health with animal health. Bartonella infection is a zoonotic disease transmitted by having contact with an infected animal that affects mostly owners of infected dogs, veterinarians, and veterinary technicians.

The first incidence of Bartonella infection in a dog got discovered in 1993 in Dr. Breitschwerdt's laboratory. Tumbleweed, a 3-year-old female yellow Labrador Retriever, had been unsuccessfully treated for nine months when she arrived at the North Carolina State Veterinary Hospital extremely ill with endocarditis, an inflammation of the inner lining of the heart chambers and valves.

"I wanted to know how we had missed the diagnosis of bartonellosis in the past,” Dr. Breitschwerdt explains. 

Bartonella is the number one cause of culture-negative endocarditis in humans and dogs equally, with many of the genera of Bartonella affecting both species. In 2008, an article published in The Lancet Oncology stated that approximately 2 million human cancer (16.6%) cases were believed to be caused by infectious agents such as bacteria and viruses. Fast forward to 10 years, another review suggested that infections are now estimated to be responsible for 25 or 50% of all human cancers. 

"I've been trying to convince pharmaceutical companies, many of which I lectured for and consulted with for over 30 years, that Bartonella is an important, emerging pathogen that induces chronic infection (inflammation) and a spectrum of diseases in pets and people." Dr.Breitschwerdt claims in this commentary

Bartonella infection has a stealthy nature; it works by invading, thriving, and hiding inside cells of blood vessel walls throughout the body. Its protein keeps the cells alive longer than they ordinarily would live and turns on pro-inflammatory genes. All these mechanisms could lead to the development of a cancerous cell and subsequential cancer, including the development of vasoproliferative tumors. Bartonella is exceedingly difficult to diagnose. Serology can be negative despite persistent infection. Treatment generally requires more than one antibiotic to eliminate. Can this bacteria contribute to cancers such as hemangiosarcoma that are not antibiotic reversible? 

This post was divided due to its substantial length and the abundance of valuable information it holds. Dr. Breitschwerdt's response can be found in Part 2.


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