Bartonella species cause 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 localised (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.
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.
The three most common infections described in humans include: cat-scratch disease (B henselae); Carrion's disease (B bacilliformis), which consists of a bacteraemic phase (Oroya fever) and an eruptive phase (verruga peruana or Peruvian wart); and trench fever (B quintana).
Bartonella species are responsible for a broad spectrum of clinical syndromes, including prolonged fever of unknown origin, haematological manifestation, encephalitis and encephalopathy, generalised lymphadenopathy, hepatosplenic disease, retinopathy, culture-negative endocarditis, osteomyelitis, arthritis, mediastinal mass, and pleurisy.
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.
Although predominantly an animal species, B vinsonii subsp. berkhoffii has been noted to cause human disease. 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.
History and exam
Key diagnostic factors
- 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)
Other diagnostic factors
- gastrointestinal symptoms
- bone and joint pain (trench fever)
- severe pallor (Oroya fever)
- hepatosplenomegaly (Oroya fever)
- dyspnoea, 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 haemorrhages (CSD, trench fever)
- chest pain
- gastrointestinal bleeding
- cat scratches and bites
- exposure to arthropod vectors
- homelessness or poor living conditions
- exposure to ticks
1st investigations 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's disease)
- culture: Bartonella bacilliformis (Carrion's disease)
- serology: B bacilliformis (Carrion's disease)
- immunofluorescence antibody (IFA) assay: B vinsonii
- polymerase chain reaction (PCR) assay: B vinsonii
- culture: B vinsonii
Investigations 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's disease)
- CT abdomen
- lumbar puncture with cerebrospinal fluid (CSF) analysis
- bone scan
suspected Bartonella endocarditis
cat-scratch disease: no endocarditis, hepatic involvement or bacillary angiomatosis
trench fever: no endocarditis or bacillary angiomatosis
peliosis hepatis or hepatosplenic micro-abscesses
confirmed Bartonella endocarditis
Carrion's disease: Oroya fever
Carrion's disease: verruga peruana
Bartonella vinsonii infection
- Bacterial adenitis
- Infectious mononucleosis
- Cytomegalovirus infection
- CDC health information for international travel (yellow book): Bartonella infections
- 2015 ESC guidelines for the management of infective endocarditis
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