Bartonella infections
Bartonella infections, known as bartonellosis, are caused by bacteria from the Bartonella genus, with over twenty species identified, ten of which can infect humans. These infections can present in various forms, including Oroya fever, cat scratch fever, trench fever, endocarditis, bacteremia, and bacillary angiomatosis. Transmission typically occurs through bites from fleas, ticks, sandflies, or through animal bites or scratches, allowing the bacteria to enter the bloodstream and potentially affecting various body systems.
Symptoms vary based on the specific Bartonella species and the severity of the infection, ranging from fever and jaundice to severe headaches and swollen lymph nodes. Diagnosis often involves a combination of epidemiological data and laboratory tests, including polymerase chain reaction testing. While mild cases may not require treatment, those with severe infections or compromised immune systems might be prescribed antibiotics. Preventive measures are particularly important for immunocompromised individuals, who are advised to limit exposure to pets, as animals serve as a significant reservoir for these bacteria. Understanding the risks and symptoms associated with Bartonella infections can be crucial for timely diagnosis and treatment.
Bartonella infections
- ANATOMY OR SYSTEM AFFECTED: All
- ALSO KNOWN AS: Bacillary angiomatosis, bacteremia, bartonellosis, cat scratch fever, endocarditis, Oroya fever, trench fever, urban trench fever
Definition
The bacterium Bartonella is a member of the family Bartonellaceae. An infection by these bacteria is called bartonellosis. Bartonella is named for Alberto Leonardo Barton Thompson, who discovered B. bacilliformis in 1905 as the cause of Oroya fever, also known as Carrion’s disease.
Twenty-four species of Bartonella have been identified, ten of which cause infectious diseases in humans. Bartonella infections include Oroya fever, cat scratch fever, trench fever, endocarditis, bacteremia, and bacillary angiomatosis.
Causes
Bartonella infection is caused by Bartonella bacteria entering the bodies of humans and other mammals by the bites of fleas or sandflies or by animal bites or scratches. The bacteria travel through the bloodstream and cause infections that can be mild or life-threatening, involve different body systems and organs, and present in different ways. Though it was once believed that ticks can spread Bartonella to humans, modern scientific research has failed to produce evidence for this vector of infection.
Risk Factors
During World War I, factors such as malnutrition, poor hygiene, alcohol abuse, compromised immunity, as well as flea and fly infestations led to an infection from B. quintana that came to be called trench fever. Epidemic fever led to widespread morbidity of troops and prisoners. Today, some of these same factors occur in homeless populations, leading to the reemergence of infection. This “new” infection is referred to as urban trench fever. Also, researchers have determined that veterinary and animal shelter staff and animal groomers and trainers are at an increased risk for Bartonella infection because of daily exposure to animals, animal feces, and parasites.
Symptoms
Symptoms of Bartonella infection depend on the bacteria involved and on the degree of infection. One of the most common infections, Oroya fever, has initial symptoms of fever, jaundice, and anemia. Once Oroya fever has progressed from the acute to chronic phase, infected persons develop verruga peruana (Peruvian warts), which are blood-filled warts. Trench fever may present with symptoms of high fever, severe headache, eye pain, and muscle pain in the back and shins. Cat scratch fever, caused by B. henselae, may present as swollen lymph nodes but then progresses to much more severe symptoms and conditions, such as encephalopathy, convulsions, and hepatitis.
Screening and Diagnosis
Screening and diagnosis of Bartonella infection relies on epidemiologic data for an affected population and confirmation by laboratory evaluation. Because of the wide range of presenting symptoms and organ involvement, diagnosis is most commonly made using polymerase chain reaction testing and serology to detect antibodies. The Centers for Disease Control and Prevention recommends an immunofluorescent antibody assay.
Treatment and Therapy
Persons with otherwise healthy immune systems often do not receive treatment for mild or moderate Bartonella infection, but severely infected persons or those with compromised immune systems may be treated with a course of oral or intravenous antibiotic drugs such as erythromycin, doxycycline, and azithromycin.
Prevention and Outcomes
Animals and household pets represent a large reservoir for many types of Bartonella bacteria that may infect humans. Immunocompromised persons should limit animal or pet exposure.
Bibliography
"About Bartonella." Centers for Disease Control, 15 May 2024, www.cdc.gov/bartonella/about/index.html. Accessed 3 Feb. 2025.
Lamps, L. W., and M. A. Scott. “Cat-Scratch Disease: Historic, Clinical, and Pathologic Perspectives.” American Journal of Clinical Pathology 121, suppl. (2004): S71-80.
Maguiña, Ciro, Guerra, Humberto, and Palmira Ventosilla. “Bartonellosis.” Clinics in Dermatology 27 (2009): 271-280.
Marquardt, William C., ed. Biology of Disease Vectors. 2d ed. New York: Academic Press/Elsevier, 2005.
Minnick, Michael F., and James M. Battisti. “Pestilence, Persistence, and Pathogenicity: Infection Strategies of Bartonella.” Future Microbiology 4 (2009): 743-758.
Schaller, James L. The Diagnosis, Treatment, and Prevention of “Bartonella”: Atypical “Bartonella” Treatment Failures and Forty Hypothetical Physical Exam Findings. Tampa, Fla.: Hope Academic Press, 2008.