Bartonella infection

Overview 
Theory 
Diagnosis 
Management 
Follow up 
Resources 

Last reviewed: 11 Aug 2025

Last updated: 13 Jun 2023

Bartonella infection causes severe clinical syndromes in humans. The three most important pathogens responsible for the majority of infections are B henselae, B quintana, and B bacilliformis.

Some species are worldwide in distribution (B henselae), whereas others are geographically localized (B bacilliformis).

Bartonella species are transmitted from an infected natural host to the susceptible human host either by direct contact (cat bite or scratch for B henselae) or via an insect vector (body lice for B quintana, sand fly for B bacilliformis).

Bartonella species infect erythrocytes and cause vascular proliferation, giving rise to prolonged fever, lymphadenopathy, and hepatosplenomegaly.

Laboratory diagnosis is established by culture, serology, or histopathology. Molecular techniques such as polymerase chain reaction are useful for blood and tissue specimens, including heart valves, where available.

Treatment depends on the species of Bartonella and the type of clinical presentation, but usually consists of antibiotic therapy. In some cases (e.g., cat-scratch disease), needle aspiration may be necessary.

Definition

Human bartonellosis is caused by Bartonella, a genus of facultative intracellular bacteria. Since 1993, 45 Bartonella species have been identified, some of which have been reported to cause human infections.[1][2][3]

The three most common infections described in humans include: cat-scratch disease (B henselae); Carrion disease (B bacilliformis), which consists of a bacteremic phase (Oroya fever) and an eruptive phase (verruga peruana or Peruvian wart); and trench fever (B quintana).[4][5]

Bartonella species are responsible for a broad spectrum of clinical syndromes, including prolonged fever of unknown origin, hematologic manifestation, encephalitis and encephalopathy, generalized lymphadenopathy, hepatosplenic disease, retinopathy, culture-negative endocarditis, osteomyelitis, arthritis, mediastinal mass, and pleurisy.[4][5]

B henselae and B quintana are also known to cause bacillary angiomatosis in people who are immunocompromised.[4][5]

Human infections caused by other species of Bartonella (e.g., B vinsonii, B elizabethae, B clarridgeae, B grahamii, B alsatica, B rochalimae, B washoensis, and B koehlerae) do occur but are rare.[5][6][7][8][9][10][11]

Although predominantly an animal species, B vinsonii subsp. berkhoffii has been noted to cause human disease.[12] Infections caused by B vinsonii subsp. arupensis in humans have been reported in France, Russia, and Nepal causing febrile illnesses, suggesting they are geographically widespread.[13]

This topic focuses mainly on the three most common infections described in humans: cat-scratch disease; Carrion disease; and trench fever.

History and exam

Key diagnostic factors

fever
skin manifestations (cat-scratch disease [CSD])
lymphadenopathy (CSD, Oroya fever)
episodic abdominal pain (CSD)
headache, post-orbital (trench fever)
maculopapular rash (trench fever)
nodular skin lesions (verruga peruana, Peruvian wart)

Full details

Other diagnostic factors

gastrointestinal symptoms
bone and joint pain (trench fever)
severe pallor (Oroya fever)
hepatosplenomegaly (Oroya fever)
dyspnea, heart murmur, and signs of cardiac failure (CSD, trench fever)
mental state changes (CSD, Oroya fever)
nuchal rigidity (CSD)
red eye (CSD, trench fever)
painless visual loss, with unilateral, abrupt onset (CSD)
bone pain (CSD)
mastoiditis (CSD)
Janeway lesions, Osler nodes, or splinter hemorrhages (CSD, trench fever)
chest pain
photophobia
gastrointestinal bleeding

Full details

Risk factors

cat scratches and bites
exposure to arthropod vectors
homelessness or poor living conditions
history of cardiac valvular disease
immunosuppression

Full details

Diagnostic tests

1st tests to order

serology: Bartonella henselae (cat-scratch disease [CSD])
culture: B henselae (CSD)
aspiration or biopsy of lymph nodes (CSD)
serology: B quintana (trench fever)
culture: Bartonella quintana (trench fever)
blood smear (Carrion disease)
culture: Bartonella bacilliformis (Carrion disease)
serology: B bacilliformis (Carrion disease)
culture: B vinsonii
immunofluorescence antibody (IFA) assay: B vinsonii
polymerase chain reaction (PCR) assay: B vinsonii

Full details

Tests to consider

PCR: B henselae (CSD)
tuberculin skin testing (TST)
interferon-gamma release assays (IGRA)
PCR: B quintana (trench fever)
tissue biopsy (trench fever)
tissue biopsy (Carrion disease)
echocardiogram
CT abdomen
lumbar puncture with cerebrospinal fluid (CSF) analysis
bone scan

Full details

Treatment algorithm

INITIAL

suspected Bartonella endocarditis

ACUTE

cat-scratch disease: no endocarditis, hepatic involvement or bacillary angiomatosis

trench fever: no endocarditis or bacillary angiomatosis

bacillary angiomatosis

peliosis hepatis or hepatosplenic microabscesses

confirmed Bartonella endocarditis

Carrion disease: Oroya fever

Carrion disease: verruga peruana

Bartonella vinsonii infection

Contributors

Authors

Janak Koirala, MD, MPH, FACP, FIDSA

Professor Emeritus of Medicine

Division of Infectious Diseases

Southern Illinois University School of Medicine

Springfield

Disclosures

JK declares that he has no competing interests.

Vidya Sunadareshan, MD, MPH

Professor of Medicine

Chair, Division of Infectious Diseases

Southern Illinois University School of Medicine

Springfield

Disclosures

VS declares that she has no competing interests.

Sangita Basnet, MD, FAAP

Professor of Pediatrics

Department of Pediatrics

Southern Illinois University School of Medicine

Springfield

Disclosures

SB declares that she has no competing interests.

Peer reviewers

Russell Wesley Steele, MD

Professor of Pediatrics and Infectious Diseases

Tulane University School of Medicine

New Orleans

Disclosures

RWS declares that he has no competing interests.

Miguel G. Madariaga, MD, MSc

Infectious Diseases Consultant

Naples Community Hospital

Naples

Disclosures

MGM declares that he has no competing interests.

Katarina Westling, MD, PhD

Division of Infectious Diseases

Karolinska University Hospital

Huddinge

Stockholm

Sweden

Disclosures

KW declares that she has no competing interests.

Peer reviewer acknowledgements

BMJ Best Practice topics are updated on a rolling basis in line with developments in evidence and guidance. The peer reviewers listed here have reviewed the content at least once during the history of the topic.

Disclosures

Peer reviewer affiliations and disclosures pertain to the time of the review.

References

Our in-house evidence and editorial teams collaborate with international expert contributors and peer reviewers to ensure that we provide access to the most clinically relevant information possible.

Key articles

Maguina C, Gotuzzo E. Bartonellosis. New and old. Infect Dis Clin North Am. 2000 Mar;14(1):1-22;vii. Abstract

Rolain JM, Brouqui P, Koehler JE, et al. Recommendations for treatment of human infections caused by Bartonella species. Antimicrob Agents Chemother. 2004 Jun;48(6):1921-33.Full text Abstract

Florin TA, Zaoutis TE, Zaoutis LB. Beyond cat scratch disease: widening spectrum of Bartonella henselae infection. Pediatrics. 2008 May;121(5):e1413-25. Abstract

Centers for Disease Control and Prevention. Bartonella infection. Jan 2022 [internet publication].Full text

Prutsky G, Domecq JP, Mori L, et al. Treatment outcomes of human bartonellosis: a systematic review and meta-analysis. Int J Infect Dis. 2013 Oct;17(10):e811-9.Full text Abstract

Reference articles

A full list of sources referenced in this topic is available to users with access to all of BMJ Best Practice.

Differentials
- Bacterial adenitis
- Infectious mononucleosis
- Cytomegalovirus infection
More Differentials
Guidelines
- CDC health information for international travel (yellow book): Bartonella infections
- Guidelines for the prevention and treatment of opportunistic infections in adults and adolescents with HIV: bartonellosis
More Guidelines
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Bartonella infection

Summary

Definition

History and exam

Key diagnostic factors

Other diagnostic factors

Risk factors

Diagnostic tests

1st tests to order

Tests to consider

Treatment algorithm

suspected Bartonella endocarditis

cat-scratch disease: no endocarditis, hepatic involvement or bacillary angiomatosis

trench fever: no endocarditis or bacillary angiomatosis

bacillary angiomatosis

peliosis hepatis or hepatosplenic microabscesses

confirmed Bartonella endocarditis

Carrion disease: Oroya fever

Carrion disease: verruga peruana

Bartonella vinsonii infection

Contributors

Authors

Janak Koirala, MD, MPH, FACP, FIDSA

Disclosures

Vidya Sunadareshan, MD, MPH

Disclosures

Sangita Basnet, MD, FAAP

Disclosures

Peer reviewers

Russell Wesley Steele, MD

Disclosures

Miguel G. Madariaga, MD, MSc

Disclosures

Katarina Westling, MD, PhD

Disclosures

Peer reviewer acknowledgements

Disclosures

References

Key articles

Reference articles

A full list of sources referenced in this topic is available to users with access to all of BMJ Best Practice.

Differentials

Guidelines

Log in or subscribe to access all of BMJ Best Practice

Log in or subscribe to access all of BMJ Best Practice

Log in to access all of BMJ Best Practice