An Overview of the Different Types of Bartonella & How They’re Spread

Bartonella is one of the most common types of bacteria in the world. While most people are familiar with the Bartonella infection known as Cat Scratch Disease, species of Bartonella can cause other diseases too. What’s more, Bartonella can be spread by ticks, making Bartonellosis an emerging tick-borne disease. Keep reading to learn more about the different types of Bartonella, how they are spread, and what diseases they cause.

What is Bartonella?

Bartonella is a group of bacteria that can cause disease in humans, one of which is Cat Scratch Disease (sometimes called Cat Scratch Fever). Cats typically contract the bacteria from the bites or droppings of fleas or lice, then spread it to humans. Specifically, if a cat is infested with infected fleas and then scratches itself, bacteria can contaminate the cat’s claws, and the cat can then infect a human by scratching them – hence the name “Cat Scratch Disease.”

However, like the bacteria that cause Lyme disease and Tick-Borne Relapsing Fever, Bartonella is actually a group of bacteria – in this case, including at least 37 distinct species. These species have different reservoir hosts, and about half of them can cause a range of diseases in humans, including:

• Cat Scratch Disease/Cat Scratch Fever
• Trench Fever
• Carrión’s Disease
• Complications including bacillary angiomatosis and subacute endocarditis

This means that accurate diagnosis of a Bartonella infection requires testing technology designed to detect different species of the bacteria.

While most cases of Bartonellosis disease are spread through the bites or scratches of infected cats, Bartonellosis has also been found to be spread by ticks. In fact, the same blacklegged ticks (also known as deer ticks) that cause Lyme disease have been found to carry and transmit Bartonella.

Some Common Species of Bartonella

As mentioned above, the disease and symptoms caused by a Bartonella infection depend on what species of Bartonella has been transmitted. Covered below are a few common types of Bartonella, their reservoir hosts, their vectors (how they are transmitted), and the diseases they cause.

Some Common Species of Bartonella

As mentioned above, the disease and symptoms caused by a Bartonella infection depend on what species of Bartonella has been transmitted. Covered below are a few common types of Bartonella, their reservoir hosts, their vectors (how they are transmitted), and the diseases they cause.

B. henselae

Reservoirs: Cats

Vectors: Fleas, ticks

B. henselae is the causative agent of Bartonellosis, or Cat Scratch Disease. It is named after clinical microbiology technologist Diane Marie Hensel, who collected strains and samples of the bacteria in 1985. The bacteria was officially classified in 1992.

B. henselae is transmitted to cats from fleas or lice, and most often from cats to humans. However, it can also be spread to humans by cat or dog fleas, and by ticks.

In addition to CSD, B. henselae can also cause bacillary angiomatosis, peliosis hepatis, endocarditis, bacteremia with fever, neuroretinitis, meningitis, and encephalitis.

B. quintana

Reservoirs: Cats, humans

Vectors: Lice

B. quintana is the causative agent of trench fever. It is most closely associated with a major outbreak among soldiers in Europe during World War I (hence the name “trench fever”), but has also caused outbreaks among refugees in subsequent decades. This is because it is spread from human to human through the body louse, which commonly affects people crowded in close quarters with poor access to sanitation and hygiene.

B. quintana has been around for millennia, as evidenced by DNA from the bacteria found in a 4,000-year-old tooth.

B. elizabethae

Reservoirs: Rats

Vectors: Fleas

Classified in 1993, B. elizabethae – like other types of Bartonella – causes disease in both humans and animals. Most commonly, it causes endocarditis, or inflammation of the inner layer of the heart tissue. It has been found to disproportionately affect homeless intravenous drug users in major cities in the U.S. and Sweden.

B. bacilliformis

Reservoirs: Humans

Vectors: Sand flies

B. bacilliformis is the causative agent of Carrión’s disease, which only affects humans and causes what are known as “Peruvian warts” and other rashes or lesions during the second (chronic) phase. The disease was named after Daniel Alcides Carrión García, a Peruvian medical student who discovered it, and is most common in high-altitude regions of South America.

Other types of Bartonella & how they are spread

As mentioned, about half of the 37 known species of Bartonella can cause disease in humans. Some of those species are outlined in the following table:

Not just cats

Although CSD and other Bartonella infections are most closely associated with cats, they can also infect dogs, and be spread to humans via dog fleas or ticks. Six of the Bartonella species mentioned above are known to infect canines:

• B. henselae

• B. vinsonii

• B. clarridgeiae

• B. elizabethae

• B. woshoensis

• B. quintana

The most common reported species infecting dogs is B. henselae, which is responsible for Cat Scratch Fever.

The dangers of Bartonella infections

As you can see, Bartonella infections produce a diversity of symptoms and diseases that can range from mild to life-threatening. Many diseases associated with Bartonella are especially dangerous for immunocompromised patients, such as those with HIV, cancer, or other chronic infectious diseases. Since Bartonella is such a common type of bacteria with so many different species, it’s important that medical professionals use the latest technology in diagnostic testing to make sure patients with relevant symptoms get an accurate diagnosis.

Learn more about symptoms and testing for Bartonella infections in IGeneX’s Tick Talk blog.