Bartonellosis consists of a large group of infections caused by Bartonella species. Bartonella are ubiquitous bacteria that can be transmitted by the bites of a broad range of arthropod vectors (in other words, bug bites) and by contact with body fluids and tissues from infected animals.   Some bugs that spread bartonella include fleas, lice, ticks, and biting flies.  Even spiders and ants have been published to transmit bartonella and cause human infection,  and other bugs are suspected, like mites.   These stealthy microbes are highly adapted to living in mammalian hosts and are associated with a broad spectrum of diseases in both humans and animals.

Bartonellosis is considered an emerging infectious disease. Medical science knew of only 2  Bartonella species before 1990, but now we know of more than 40, approximately 20 of those species thus far demonstrated to cause human disease. Bartonella henselae, the causative agent of Cat Scratch Disease (CSD), is thought to be the most prevalent species found in humans in the United States, but we’re really not sure of this because the testing for the other species is largely unavailable.   Although the first case of CSD was described in the 1950s, B. henselae wasn’t identified until HIV came along.  Immune-suppression from HIV changed how bartonella presented clinically and microbiologically, and was instrumental in the discovery of this bacteria in the 1990’s.  Because of this, bartonellosis was initially believed to primarily affect immunocompromised individuals, which it turns out, is incorrect.   Immunocompetent people frequently become chronically infected, and may experience a spectrum of manifestations ranging from asymptomatic to life-threatening infection, and anything in between.  When bartonellosis results in significant illness, these chronic infections cause cardiac, rheumatologic, neurologic, and hematologic disease which can be very serious.

Stereotypes can lead us astray.  Some reported cases are too often focused on acute presentations of CSD, Trench Fever, and Carrion’s Disease, making them easier to diagnose. Acute infections are likely to be diagnosed and treated quickly, but the outcome is remarkably more challenging for chronically ill patients who can go years without a correct  diagnosis.. Although we review these stereotypical presentations below because awareness of them may provide diagnostic insight into the more common and complex presentations,  please know that to rigidly restrict bartonella diagnosis to these narrow clinical presentations may be a grave disservice, resulting in a missed diagnosis.

Bartonellosis Stereotypes

Cat Scratch Disease (Bartonella henselae)

Cat Scratch Disease (CSD) is a bartonellosis diagnosed in humans and animals across the United States. Bartonella henselae, the causal agent, is transmitted from a mammal reservoir to a human either through arthropod vectors, as detailed above, or by a cat scratch or bite, hence the name. The principal reservoir animal for this species is a cat, but it’s also been found in horses, dogs, and wild animals, for example bats.

Major symptoms may not manifest for several days, or even weeks after original exposure.

3 – 10 Days After Exposure

A painless, red spot may appear on the skin where the infection or exposure occurred. The spot usually won’t itch, but will possibly fill with fluid, ultimately crusting over and healing with a scar. The spot can last 1 – 3 weeks.

1 – 3 Weeks After Exposure

Lymph nodes start to swell, predominantly near the source of the infection. Underarms, neck, and groin regions are most frequently affected. Skin may feel hot and become red, and the lymph nodes might feel sore and tender. This typically persists for approximately 2 – 4 months, but may persist for up to a year or even longer. Initially thought to be a “self-limited illness” in immunocompetent patients, we now know that this is not the rule and that serious consequences can result.

Trench Fever (Bartonella quintana)

Trench Fever is a widespread manifestation of bartonellosis that is thought to be  chiefly transmitted by human body lice and is prevalent among the homeless population. It is notorious for having caused, fever, headache, and leg pain in excess of one million soldiers in Europe during World War I. These soldiers suffered from poor hygiene and unsanitary conditions that became a breeding ground for arthropod vectors like body lice. Although Trench Fever has been around for a long time, the causative agent, Bartonella quintana, was only isolated in 1960.  Mammalian transmission of this pathogen also occurs and was documented in 2007 when a North Carolina woman tested positive after being bitten by a feral cat.

Symptoms can manifest between a couple of days to 5 weeks after the original exposure.

4 – 15 Days After Exposure

Recurrent fevers which can  persist for approximately 4 – 5 days at a time.

Weeks to Months After Exposure

Most people recover from the actual recurrent fevers within two months, but some develop relapsing or significant chronic multisystem illness,

Carrion’s Disease (Bartonella bacilliformis)

In 1885, Daniel Carrion. a Peruvian medical student, inoculated himself with fluid from verruga peruana lesions in order to document the symptoms that followed; he died 5 weeks later of the illness which now bears his name. In 1909, its cause,  Bartonella bacilliformis, was discovered. It’s primarily transmitted by the bite of infected sand flies in Peru, Ecuador, and Columbia. In spite of being geographically isolated, cases have also been described in travelers to South America months to years after returning to non-endemic countries. Primary symptoms typically start to manifest between 3 and 12 weeks after Bartonella exposure.

3 Weeks After Exposure

This infection frequently presents itself as a severe, life-threatening illness, referred to as Oroya Fever, which can sometimes have a case fatality rate as high as 80% without intensive care invention and antibiotic treatment,

Weeks to Months After Exposure

If patients don’t receive treatment but manage to survive Oroya Fever, they may enter the second phase of Carrion’s Disease, also known as verruga peruana (Peruvian warts). Reddish-purple nodules develop on the skin, although in some cases, this  can also progress to internal organs.  With proper antibiotic  treatment, Carrion’s Disease can subside within a few weeks, but for some patients, it can take years to subside.

Chronic Bartonellosis

Chronically ill bartonellosis patients typically present with multi-system illness, symptoms of which can resolve and relapse in a cyclic pattern. What’s more, concurrent infections with other bacteria (Borrelia burgdorferi and others.) and parasites (Babesia microti and others) further complicate the clinical features of chronic bartonellosis. It’s routinely written in various medical journal articles that these chronic infections are often mistaken for “other disorders,” such as autoimmune diseases (rheumatoid arthritis, psoriasis, lupus, etc.)–But conclusions drawn from both the medical literature and the clinical practice of not only Dr. Phillips, but countless of his colleagues around the world point to something more paradigm changing.  And it’s the premise of our book. In Chronic–The Hidden Cause of the Autoimmune Pandemic and How to Get Healthy Again, we provide evidence that it’s not a matter of misdiagnosis or of mimicking, but rather one of causation.  It’s often been said that when medical science finds a cause of one autoimmune condition, we’ll find the cause of all of them. This may be close to the truth.  It’s likely the occult bartonella infection causes a broad swath of chronic and autoimmune disease, but it’s not the only cause any single condition. There are other infections that can result in overlapping disease manifestations.

Bartonella Endocarditis

Endocarditis is an infection of the inner lining and valves of the heart, usually caused by bacteria, but can be caused by other microbes as well.. Endocarditis characteristically presents with non-specific clinical signs like chills, fever, fatigue, or muscle pain, but can be very serious, even fatal, sometimes requiring cardiac surgery.  When imaging shows the disease, physicians will collect samples to culture so a causal pathogen can be identified.

The problem is that not all bacteria can be readily cultured, and these are referred to as fastidious organisms.  Bartonella is one such organism and is a leading cause of culture-negative endocarditis,  Since 1993, a wide spectrum of Bartonella species have increasingly been implicated in human endocarditis.  Given that endocarditis is such a serious disease, if cultures are negative, bartonella should always spring to the list of suspects.

Bartonella Risk Factors

  • Exposure to fleas, lice, biting flies, ticks, spiders, ants, and potentially other arthropods.
  • Working or living with pets or other animals.

Risks for developing severe illness

  • People with innately weaker immune systems (younger children, adolescents, aging adults).
  • Cancer patients, people with weakened  immune, or patients using immunosuppressants (such as steroid therapy).

Bartonella Laboratory Diagnosis

Successful Bartonellosis diagnosis can be challenging.  Non-specific symptoms are common and even serious bartonella infections with false negative blood tests have been repeatedly documented in the medical literature.

Some current methods include:

Culturing means to grow the bacteria from clinical samples such as blood, body fluids, or body tissues.  Although some advancements have been made in this area by specialty labs, we’re still a good ways off from having a high sensitivity culture test even in those labs and false-negative culture tests are common even in active bartonellosis..

Serology means looking for antibodies that our bodies make against the infection.  It’s not a direct detection test and therefore can’t be relied upon to  document persistent infection or clearance of infection.

PCR (Polymerase Chain Reaction) is a method of amplifying bacterial DNA so that it can be detected. Being a direct detection test, it can document persistence of infection when positive.   For additional certainty of positive results, DNA amplified by PCR can be sequenced to make sure it does not represent a false- positive result.  False negative results occur and are not uncommon.