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Capnocytophaga canimorsus meningitis and bacteraemia without a dog bite in an immunocompetent individual
  1. Fiona O'Riordan1,
  2. Aoife Ronayne2 and
  3. Arthur Jackson3
  1. 1General Medicine, Mercy University Hospital, Cork, Ireland
  2. 2Microbiology, Mercy University Hospital, Cork, Ireland
  3. 3Infectious Diseases, Mercy University Hospital, Cork, Ireland
  1. Correspondence to Dr Fiona O'Riordan; fionaoriordan85{at}


We describe the case of an immunocompetent 75-year-old man with Capnocytophaga canimorsus bacteraemia and meningitis. C. canimorsus is commonly found in the oral flora of dogs with human infection typically occurring following a bite. Unusually, while our patient was a dog owner, there was no history of bite nor scratch mark. Admission blood cultures flagged positive for Gram-negative bacilli, but prolonged molecular analysis was required before C. canimorsus was isolated in blood and cerebrospinal fluid. There is a high mortality rate in invasive infection, and in our patient’s case, antibiotic therapy was commenced prior to laboratory confirmation with our patient making a complete recovery. This case highlights the importance of including C. canimorsus in the differential diagnosis of unwell patients who keep dogs, even without a bite. This case occurred amid heightened awareness of COVID-19, which may represent predisposition for zoonoses during social isolation and increased human–pet contact.

  • infectious diseases
  • infection (neurology)
  • immunology
  • meningitis

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  • Contributors Substantial contributions to the conception or design of the case report was contributed by FO'R, AJ and AR. Analysis, or interpretation of data for the case report was contributed by FO'R, AJ and AR. Drafting the work or revising it critically for important intellectual content was contributed by FO'R, AJ and AR. Final approval of the version to be published was contributed by FO'R, AJ and AR. Agreement to be accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved by FO'R, AJ and AR.

  • Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.

  • Competing interests None declared.

  • Provenance and peer review Not commissioned; externally peer reviewed.