Bartonella: Not a tick-borne disease or Lyme coinfection

posted in: Science vs myths | 0

Fake Bartonella infections

In chronic Lyme groups, patients are often misled into believing they have multiple fake diseases, not just “chronic Lyme”. Particularly common are fake Bartonella infections. The CDC debunks some common myths about Bartonella, which is a genus of bacteria.

According to the CDC:

  • There is currently no convincing evidence that ticks can transmit Bartonella infection to humans.
  • Unfortunately there is a great deal of misinformation regarding multiple tickborne infections (called coinfections) on the internet. The possibility of having several tickborne infections at once or having pathogens such as Bartonella that have not been shown to be tickborne, is extremely unlikely.

Since Lyme bacteria (Borrelia burgdorferi) is only spread by black legged (Ixodes) ticks and Bartonella is not a tick-borne infection, Bartonella is not a coinfection of Lyme disease. Unfortunately, false claims of multiple coinfections are made by quacks and their patients, who are victims.

In a 2013 survey by quackery propaganda group, 54% of respondents claiming to have chronic Lyme disease—itself an unrecognized diagnosis— also claimed to have a Bartonella coinfection. As detailed in our post on tick-borne infections in the United States, the survey results defy reality.

But what about positive tests?

Confusion may be caused by inappropriate use of testing. Many people produce antibodies to Bartonella bacteria, but this does not mean that Bartonella is causing symptoms. In a study of Italian children, 62% had antibodies to Bartonella but no evidence of cat-scratch disease. Another study found 30% of Germans produce antibodies to Bartonella.

In addition, CDC scientists have called into question certain PCR (DNA) tests that have not been validated. The scientists criticized one study which inexplicably claimed many subjects tested positive for Bartonella DNA by PCR and yet did not test positive for Bartonella antibodies. Since a Bartonella infection typically provokes an immune response, the scientists questioned the contradictory and implausible results of the study.

Ultimately, a positive test is not necessarily meaningful. Because of the confusion surrounding testing, the CDC advises, “It is important for all abnormal test results to be interpreted with your health care provider in the context of your medical history.”

Doctors are very concerned about patients who have been diagnosed with false Bartonella infections because the patients may receive unnecessary treatments and delay treatment for a real conditions. One exasperated doctor stated, “now one of my patients is arguing and menacing because I do not confirm his infection by Bartonella spp.”

LymeScience recommends against patronizing the following labs: Galaxy Diagnostics, IgeneX, DNA Connexions, ArminLabs, and others listed on our Red Flags of Lyme Quackery page.

Fake Bartonella photos flood the Internet

Cat-scratch disease is caused by infection with bacteria called Bartonella henselae. According to the CDC, typical symptoms include:

  • Low-grade fever may be present
  • Enlarged, tender lymph nodes that develop 1–3 weeks after exposure
  • A papule or pustule at the inoculation site

This is a photo of real papules caused by Cat-scratch disease:

Two Bartonella papules
Cat-scratch disease lesions or papules, one week after contracting Bartonella (Source: Mazur-Melewska-et-al, copyright CC By 4.0)


In chronic Lyme groups, dubious photos of rashes are commonly presented as evidence of Bartonella infection. In reality, these photos are typically stretch marks, a common skin condition also called Striae distensae. According to Medscape:

Approximately 90% of pregnant women, 70% of adolescent females, and 40% of adolescent males (many of whom participate in sports) have stretch marks.

Below is a photo of typical stretch marks:

Stretch marks
Stretch marks from a 13 year old boy (source: Wikimedia Commons)

As shown below, a search for “rash bartonella” on Google Images returns several photos that are likely stretch marks and not skin manifestations of Bartonella. The top hit is from the pseudoscience organization

No reputable science organization features photos like this of Bartonella. One of the images is just a mislabeled version of the Wikimedia stretch marks image.

What is real Bartonella?

Several Bartonella species are known to infect humans.  Bartonella henselae causes cat-scratch disease because the bacteria is transmitted to humans from a scratch of a cat. The human body louse (lice) transmits Bartonella quintana to humans, causing Trench fever. 

The National Organization for Rare Disorders states that Trench fever “is commonly found in homeless, alcoholic, and poverty-stricken populations where poor sanitation and poor hygiene often occurs.”

cat scratching
Cats cause Bartonella henselae infection, not ticks!

Dermatologists reassure the public

Upon discovery, stretch marks can seem concerning to parents and teenagers. Fortunately, scientists in the Department of Dermatology at Johns Hopkins University studied the issue in 2018 by reviewing cases of stretch marks of teenage boys, specifically in the lower back.

Regarding the studied stretch marks, the scientists found:

  • Stretch marks have nothing to do with bacterial infection, including Bartonella or Lyme disease.
  • Stretch marks are associated with rapid growth spurt, tall stature, and family history of stretch marks.
  • Stretch marks are not related to chronic medical conditions or anabolic steroid use.
  • Further medical testing is unnecessary.
  • Unsubstantiated information spread by Lyme-oriented web sites (such as,, and may cause unnecessary concerns from parents.

Bartonella treatments

Most cases of cat-scratch disease go away on their own, though a short (e.g. 4 day) course of antibiotics may be recommended. A very small subset patients, such as the immunocompromised, may develop worse symptoms and require special treatment.

According to infectious disease specialist Dr. Katarzyna Mazur-Melewska and colleagues:

One episode of cat-scratch disease confers lifelong immunity to all patients.

For Trench fever and serious complications of Bartonella, the CDC recommends consulting with an infectious disease expert and treating with antibiotics.


Given the known characteristics of Bartonella, the claims of chronic tick-borne Bartonella infections are simply not supported by science.

Despite claims by chronic Lyme activists of numerous chronic tick-borne coinfections, a 2014 scientific review concluded:

The medical literature does not support the diagnosis of chronic, atypical tick-borne coinfections in patients with chronic, nonspecific illnesses.

In other words, the diagnoses of chronic coinfections that chronic Lyme advocates have received are likely misdiagnoses.