see also:

• cat scratch disease

• Bartonella is a genus of Gram negative facultative intracellular bacteria
• Bartonella species are transmitted to humans and other mammals (which are its main reservoirs) by vectors such as ticks, fleas, sand flies, and mosquitoes.
• after infection they colonize endothelial cells and every 5 days some are released into the circulation to infects RBCs where they multiple
• homeless IVDUs are at particular risk of infection
• B. henselae is the cause of cat scratch disease
• Bartonella quintana is the cause of trench fever
• several other species may infect humans and may also cause endocarditis or septicaemia
• infection is usually self-limiting in immune competent people in whom antibiotic Rx is of unproven benefit
• infection in immunocompromised persons usually requires antibiotic Rx with macrolides, trimethoprim-sulfamethoxazole, gentamicin, ciprofloxacin, or rifampin;
• chronic Bartonella infection has been associated with neuropsychiatric conditions but needs more studies to ascertain cause / effect
  • 2019: Bartonella henselae Bloodstream Infection in a Boy With Pediatric Acute-Onset Neuropsychiatric Syndrome
  • 2020: Bartonella Associated Cutaneous Lesions (BACL) in People with Neuropsychiatric Symptoms
  • 2023: Microbes and Mental Illness: Past, Present, and Future
  • 2025: Babesia and Bartonella Species DNA in Blood and Enrichment Blood Cultures from People with Chronic Fatigue and Concurrent Neurological Symptoms
  • 2026: Postmortem evidence of Babesia and Bartonella infections in chronically ill suicidal young people - only tested six cases

• this bacteria is present in the saliva of some kittens (some believe it may be from flea faeces which contaminate scratches) which enters the human via a scratch causing cat scratch disease, or on the open eye - in which case a granulomatous conjunctivitis with preauricular LNs (Parinaud's syndrome) may occur.
• it has been shown to induce apoptosis in endothelial cells via a protein
• in July 2020, it was shown to also induce angiogenesis in endothelial cells via a protein which they named Bartonella angiogenic factor A (BafA) acting on the endothelial cell's VEGF receptor and which is the 1st known vascular endothelial growth factor (VEGF) like protein found to be produced by bacteria¹⁾
• may cause:
  • cat scratch disease
  • Parinaud's syndrome
  • cutaneous lesions:
    • striae-like serpiginous, vertical red lesions on the axillae, hips, buttocks and/or abdomen despite no steroid use or PH rapid weight gain
    • bacillary angiomatosis (red or purple cutaneous papules or plaques)
  • peliosis hepatis
  • endocarditis
  • bacteraemia with fever
  • neuroretinitis
  • meningitis
  • encephalitis

• usually transmitted by lice
• this bacteria may cause
  • trench fever
  • bacillary angiomatosis
  • endocarditis
• it produces its own version of BafA that also causes human endothelial cells to multiply
• it's DNA has been in a 4,000 yr old tooth

• this bacteria is found mainly in Peru, Ecuador and Colombia and may cause Carrion's disease (Oroya fever, Verruga peruana)