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  • Writer's pictureDr. Nicole Vumbaco | DVM

Bartonellosis: Zoonotic Concern For Animal Workers

Updated: Jun 18, 2023

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.

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 13 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, complex pain, migraines, psychiatric alterations (anxiety, depression, suicidal ideations), light sensitivity, dizziness, auto-immune disease, extreme fatigue, arthralgia/mylagia, joint disease, neuropathies, and neurodegenerative diseases like Multiple Sclerosis. You probably personally know someone struggling with one or many of these. We often blame it on the multilayered difficulties and 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).

Routes of transmission have traditionally been classified as vector-borne (ie-biting insects like fleas, sand flies or human lice), or secondary to a cat bite or scratch, typically associated with the presence of fleas. Over the last 2 decades, additional routes of transmission have been discovered and implicate animal saliva, perinatal, direct blood to blood (like a needle stick or blood transfusion) and newly identified vectors (specifically Dermacentor tick spp, and wood louse spiders).

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 and further convolute it's recognition.

Additionally, due to outdated testing methods and a general lack of awareness within medical personnel, chronic disseminated forms of Bartonella often go undiagnosed. 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 >40 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. In total, that is EIGHT different cells where Bartonella can seek refuge, gather nutrients and evade immune detection.

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. 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 that does NOT cause an antibody response. These characteristics commonly lead to negative IFA results which cause further dismissal of concern. To further complicate things, Traditional IFA only tests for 2 of the 14 species known to infect humans and remains highly unreliable. Traditional PCR is no better and carries a false negative rate of up to 90%!

Some of you may be thinking about patients with "Culture Negative Endocarditis" and remembering that Bartonella becomes a differential here. Because the bacteria is so slow to replicate (~24 hour replication rate), traditional blood cultures (plated for 5-7 days) are not sufficient. Bartonella needs at least 21 days to produce a population worthy of identification. As you know, that is not the standard operating procedure for most labs. It is important to also note that Bartonella historically does not flourish on commonly used traditional culture mediums like chocolate or blood agar. This bacteria is extremely picky about what it eats, both these mediums diminishes it's ability to replicate. Advanced microbial methods have been developed using a proprietary growth medium (called BAPGM) which enhance Bartonella's ability to thrive and replicate. This increases the likelihood of identifying it. You might be surprised to know that if you have ever submitted a Bartonella Panel through IDEXX that included cultures, PCR and ePCR, that you are in-fact utilizing this technology. This is also true for our IFA's.

IDEXX works with Galaxy Diagnostics, which was founded by Dr. Ed Breitschwerdt (a world renowned DACVIM and expert in the study of Bartonella). This is already our 'Veterinary Gold Standard' while human medicine lags behind. Thankfully, Galaxy Advanced Microbial Diagnostics does offer human testing and is one of the foremost leaders on zoonotic and vector-borne pathogens in animal workers. If you were to develop concern for infection then this laboratory would be your best shot at proper assessment and diagnosis (See pamphlet below or 'Understanding Bartonellosis' to learn more)

AVMA recently cited that 1 in 4 are disabled by the age of 60. Often times these are from well-documented chronic illnesses, syndromes and diseases that do not have a known, treatable underlying cause. Foundations like the Infection and Autoimmunity Education and Research Foundation are proving otherwise. As of June 2021, JAVMA further highlighted the growing occupational risk of bartonellosis in our field. While it is a start, it is not enough.

If you are one of those suffering from chronic illness, please consider proper testing with Galaxy Diagnostics using their "Triple-Draw Method"

The bottom-line:

If you work with animals, YOU ARE AT HIGHER RISK for Bartonella exposure.

If you seek consultation with multiple human specialists of conventional methodology then you will likely receive antiquated conventional IFA and single source PCR. This is not sufficient.

"While new human medical and veterinary research is quickly debunking traditional beliefs about these infectious bacteria, expert Dr. Edward Breitschwerdt, of North Carolina State University's College of Veterinary Medicine, wants veterinarians to sit up and take notice. The health risks appear to be very real, and they are heightened by frequent contact with sick animals".

PLEASE VETERINARY MEDICINE, familiarize yourself with some of the newest research and growing concerns surrounding the many clinical manifestations of this zoonotic disease. There is a gap in knowledge within veterinarians and our respective human counterparts (medical doctors). Being able to recognize the difference, know the risks and advocate for an answer is key. It is saving my life.

If you do not have time to dive into the research then please read the informative pamphlet on bartonella below. This is the most up to date summary, created in 2021 by Galaxy Advanced Microbial Diagnostics, a laboratory already in use within Veterinary Medicine (by way of IDEXX when ordering a bartonella panel on our animal patients)

Please read

  1. Rheumatological presentation of Bartonella koehlerae and Bartonella henselae bacteremias. A case report, 2018 (also listed in Rheumatologic Manifestations)

  2. Cat Scratch Disease and Arthropod Vectors: More to it than a Scratch? Journal of the American Board of Family Medicine, 2010.

Bartonellosis Education:

Didactic Lectures Presented by Dr. Breitschwerdt:

CME credit is available for medical professionals but anyone can create an account to attend these webinars for free.

1.0 CME. Provides an overview of the history of Bartonella spp infection, It describes the medically relevant history of bartonelloses prior to the recognition of the Human Immunodeficiency Virus (HIV) epidemic in the 1980’s. Gives an overview of medical history associated with the discovery of Cat Scratch Disease and the eventual identification of Bartonella henselae as the definitive causative agent.

1.0 CME. Provides an overview of key vectors and modes of transmission associated with Bartonella spp. infection, with special attention to ongoing debates surrounding tick transmission, perinatal transmission, and other modes, like transfusion and needlesticks.

1.0 CME. Provides an overview of Bartonella spp. infection, both pathogenic and species-adapted, in various hosts and reservoirs, including bats, cats, dogs, and people.

1.0 CME. Introduces a new postulate of comparative infectious disease for elusive, slow-growing, zoonotic, vector-borne diseases like Bartonella spp infection and describes the comparative features of Bartonellosis in dogs and people with particular attention to geographic and occupational risk factors.

1.0 CME/ 1 AAFP: Provides an overview of the major factors that influence disease expression resulting from Bartonella spp infection with particular attention to bacterial infection strategies and the histopathological progression of lesions observed in both immunocompetent and severely immunodeficient patients.

1.0 CME/ 1AAFP: Describes the advantages and limitations of different diagnostic methodologies for confirmation of Bartonella spp. infection, as well as recent advances in sample enrichment for direct detection of infection of this immune-evasive, slow-growing bacterial infection.

Visit Galaxy Diagnostics Website for more information.

Image and statistical information attained at

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