Bartonellosis: Zoonotic Concern For Animal Workers

Potential exposure to zoonotic disease is an inherent risk in veterinary medicine. We are exposed to a multitude of different vectors, reservoir hosts, animal species and infectious disease. Bartonella is one of many pathogens capable of causing chronic illness. Published in 2010 by the National Report — "Bartonellosis is no longer considered a self-limiting disease, and for some people chronic infection can be debilitating and hard to diagnose...". Now 11 years later, the evidence and data are even more concerning and should be considered urgent among our profession.

There are too many of us who suffer from chronic illness and vague inflammatory conditions. This can include fibromyalgia like symptoms, complex pain, migraines, psychiatric alterations (anxiety, depression, suicidal ideations), light sensitivity, dizziness, atypical auto-immune disease, extreme fatigue and neuropathies, like Multiple Sclerosis. You probably personally know someone struggling with one or many of these. We often blame it on the multilayered difficulties/chronic stressors our job entails but what if it’s not...my case is a perfect example.

Mounting research has shown the emerging concern and higher prevalence of Bartonellosis and Chronic Bacteremia in veterinary professionals, wildlife workers, and farmers.

"Up to 28% of symptomatic Veterinarians and over 40% of chronically ill patients have tested positive for Bartonella DNA in their blood, compared to 0% in healthy controls" (outlined in Lantos 2014 and Maggi 2012).

Symptoms can range from asymptomatic - mild - severely debilitating. This is highly dependent on the host-response (person infected), their immune status and complicating co-factors (severe stress, immune suppression, malnutrition, exposure to toxins, concurrent infection with other organisms, etc). In chronic infections, symptoms may emerge or re-emerge (seeming cyclic or like a "flare-up") after a complicating event or period of immune suppression. There are a plethora of deficiencies, hormonal dysregulations and a variable level of nutritional depletions leading to many secondary issues that plague Bartonellosis patients but further convolute it's recognition.

Additionally, chronic disseminated forms of Bartonella often go undiagnosed. This is due to outdated testing methods and a general lack of awareness within medical personnel. Traditional teaching taught us to recognize 3 major clinical profiles (Cat Scratch Disease, Trench Fever and Carrion's Disease) however this only accounted for 3 specific species of bartonella (B. henselae, B. quintana and B. bacilliformis, respectively). Currently there are >30 species that have been identified and 14 of those are capable of causing human illness. Research has revealed significant evolutionary advancements, allowing Bartonella to subvert the immune response in chronic presentations by living intracellularly. For example, "Bartonella henselae has been shown to infect erythrocytes, endothelial cells, macrophages, microglial cells and even human CD 34+progenitor cells" (113,114,115,116 - Citing Article) Recent findings have expanded this list to include dendritic cells, mast cells and fibroblasts. That is EIGHT different cell lines.

This bacteria is very slow growing and in chronic infections, rarely freely circulating in the blood stream. When it does enter the blood stream, it is for a short period as it travels to new sites to seed infection. Part of Bartonella's pathophysiology induces a coordinated and simultaneous cyclic release of bacteria from all infected areas into the bloodstream. Think about that, a simultaneous event! Not only does this make it extremely hard to capture on a single blood draw, it leads to a chronic recurrent bacteremia