From the Guidelines
Bartonella infections can manifest in various ways, including cat scratch disease, bacillary angiomatosis, and other conditions, with the most common manifestation being cat scratch disease, characterized by regional lymphadenopathy near the site of inoculation, often accompanied by fever, malaise, and sometimes a papule at the scratch site 1.
Manifestations of Bartonella Infections
The manifestations of Bartonella infections vary depending on the species involved and the patient's immune status.
- Cat scratch disease is the most common manifestation, characterized by regional lymphadenopathy near the site of inoculation, often accompanied by fever, malaise, and sometimes a papule at the scratch site 1.
- Bacillary angiomatosis presents as vascular skin lesions in immunocompromised individuals, particularly those with HIV, and can occur from either B. henselae or Bartonella quintana 1.
- Other manifestations include extranodal disease, such as central nervous system, liver, spleen, bone, and lung involvement, which develops in ≤2% of cases 1.
- The disease course varies, but lymphadenopathy generally resolves within 1–6 months, and in about 10% of cases, the nodes suppurate 1.
Diagnosis and Treatment
Diagnosis of Bartonella infections may be difficult because the organism is fastidious and difficult to grow in culture 1.
- Serological testing supports the diagnosis, although there is cross-reactivity between B. henselae and B. quintana as well as with a few other organisms 1.
- PCR is a diagnostic option, and a positive Warthin-Starry silver stain of infected lymph node tissue is useful to confirm the diagnosis, although it cannot differentiate species of Bartonella 1.
- Treatment of cat scratch disease with antimicrobial agents, such as azithromycin, has shown variable results, but a single, double-blind placebo-controlled study found that azithromycin-treated patients had a significant reduction in lymph node size 1.
From the FDA Drug Label
Bartonellosis due to Bartonella bacilliformis. The manifestations of Bartonella infections are not directly described in the drug label.
- The label only mentions that doxycycline is indicated for the treatment of Bartonellosis due to Bartonella bacilliformis 2.
From the Research
Manifestations of Bartonella Infections
- Bartonella species can cause a range of clinical diseases in humans, including cat scratch disease, bacillary angiomatosis, and others 3.
- The type and extent of disease varies significantly with the immune status of the host, with immunocompetent hosts typically experiencing granulomatous, suppurative, extracellular, and intracellular responses, while immunocompromised hosts experience vasculoproliferative responses 3.
- Infections can lead to various symptoms, including endocarditis, granulomatous inflammation in lymph nodes, liver, or spleen, central nervous system dysfunction, and inflammatory polyarthritis 4.
- Hematological abnormalities, such as thrombocytopenia, lymphocytosis, neutropenia, and eosinophilia, have been reported in B. henselae-infected cats 4.
- The clinical spectrum of Bartonella infections is expanding, with new species and clinical syndromes being identified 5, 6, 7.
Transmission and Reservoirs
- Cats are a major reservoir for human infection, particularly for Bartonella henselae, Bartonella clarridgeiae, and Bartonella koehlerae 4, 6.
- Other animals, including dogs, bovine, canine, human, and rodent species, can also serve as chronically infected reservoir hosts for various intra-erythrocytic Bartonella species 4.
- Arthropod vectors, such as fleas, ticks, biting flies, keds, lice, and sandflies, play a role in the transmission of Bartonella species to animals and humans 4, 6, 7.
Diagnosis and Treatment
- Diagnosis of Bartonella infections can be supported by serology, PCR, and culture, although documenting causation in an individual cat can be difficult due to the high rate of sub-clinical infections 4.
- Response to treatment can be used in conjunction with serology or organism isolation to support a clinical diagnosis of feline bartonellosis 4.
- Antibiotic treatment, such as erythromycin, clarithromycin, azithromycin, rifampin, doxycycline, and gentamicin, can be effective in treating Bartonella infections, particularly in immunocompromised hosts 3.