Bartonella

Bartonella is a genus of Gram-negative bacteria. It is the only genus in the family Bartonellaceae.  Facultative intracellular parasites, Bartonella species can infect healthy people, but are considered especially important as opportunistic pathogens. Bartonella species are transmitted by vectors such as fleas, sand flies, and mosquitoes.    At least eight Bartonella species or subspecies are known to infect humans.  Bartonella henselae is the organism responsible for cat scratch disease.

​History

Bartonella species have been infecting humans for thousands of years, as demonstrated by Bartonella quintana DNA in a 4000-year-old tooth. The genus is named for Alberto Leonardo Barton Thompson (1871–October 26, 1950), a Peruvian scientist.

​Infection cycle

Though some studies have found "no definitive evidence of transmission by a tick to a vertebrate host,"  Bartonella species are well-known to be transmissible to both animals and humans through various other vectors, such as fleas, lice, and sand flies. Bartonella bacteria are associated with cat-scratch disease, but a study in 2010 concluded, "Clinicians should be aware that ... a history of an animal scratch or bite is not necessary for disease transmission."  All current Bartonella species identified in canines are human pathogens.

​SUMMARY

Bartonella is a type of bacteria that can make people very sick. There are three main kinds that cause most of the infections: B. henselae, B. quintana, and B. bacilliformis.

Some of these bacteria are found all over the world (like B. henselae), but others only live in certain places (like B. bacilliformis).

People can catch Bartonella in different ways:

• B. henselae – usually from a cat scratch or bite.

• B. quintana – spread by body lice.

• B. bacilliformis – spread by sand flies.

​​Once the bacteria get into the body, they infect red blood cells and cause the blood vessels to grow abnormally. This can lead to symptoms like long-lasting fever, swollen lymph nodes, and enlarged liver or spleen.

​Doctors figure out if someone has Bartonella using lab tests. They might grow the bacteria in a culture, look for antibodies in the blood (serology), or look at tissues under a microscope. Special tests called PCR can find Bartonella DNA in blood or tissue samples, including heart valves.

​Treatment usually involves antibiotics, but the exact medicine depends on which type of Bartonella you have and how sick you are. In some cases, like with cat-scratch disease, a doctor may need to use a needle to drain swollen lymph nodes.