Bartonella henselae

Bartonella henselae

Infection: Bartonella henselae infection; cat scratch disease

Brief description:
  • Bacterial infection transmitted from infected cats via scratch, bite or other contact.
  • Most commonly affects children. Typical illness is localised infection at site of scratch, followed by regional lymphadenopathy in following weeks. Most commonly axilla or neck nodes. Can reach very large size.
  • Usually self-limiting, but rarely can involve other organs e.g. eyes, liver, spleen, heart valves.
Did you know?

Infected cats/kittens are usually <1 year old and show no symptoms of infection themselves. Higher risk if they have fleas or are known fighters. Less common to get infection from an older cat.

Who should I test?
  • Consider testing in children with multiple enlarged lymph nodes, or nodes that are not reducing in size at 2-3 weeks. Keep in mind other more serious causes of persistent lymphadenopathy.
  • Discuss with a microbiologist if infection involving other organs is suspected.
Test of choice:

Request Bartonella serology

Interpretation of serology can be complicated, and both false negatives and false positives can occur.

  • A strongly positive result generally makes the diagnosis likely, however less strong results can be difficult to interpret.
  • Interpretation of serology should take into account the pre-test probability of infection. Discuss with a clinical microbiologist if uncertain.
Tests to avoid/specialist tests:

Bartonella PCR

  • This can be performed on blood or tissue samples from affected tissues. Sensitivity can be limited, but specificity is high, so a positive result confirms the diagnosis. Only used in certain circumstances – discuss with a clinical microbiologist first.