[A treacherous pet]

Area of Science:

• Infectious Diseases
• Bacteriology
• Human-Animal Interactions

Background:

• Capnocytophaga canimorsus is a bacterium commonly found in the mouths of dogs and cats.
• Infections can occur through bites, scratches, or even casual contact, particularly with compromised skin.
• Severe manifestations, though rare, can include sepsis, meningitis, and limb amputation.

Purpose of the Study:

• To report a case of severe Capnocytophaga canimorsus infection presenting with fever, petechiae, and thrombocytopenia.
• To highlight the diagnostic challenges and treatment outcomes for this zoonotic bacterial infection.
• To emphasize the importance of considering animal contact in patients with unexplained febrile illnesses and severe thrombocytopenia.

Main Methods:

• A 63-year-old woman presented with a 5-day history of high-grade fever, petechiae, and severe thrombocytopenia.
• Physical examination revealed left inguinal lymphadenopathy and an encrusted wound on the left tibia, sustained from a piece of wood, with a history of dog licking.
• Blood cultures were performed, and Capnocytophaga canimorsus was identified after 2 days of incubation.

Main Results:

• The patient exhibited symptoms including high-grade fever, petechiae on lower legs, and severe thrombocytopenia.
• Capnocytophaga canimorsus was successfully isolated from blood cultures.
• Treatment with amoxicillin/clavulanic acid resulted in complete clinical recovery.

Conclusions:

• Capnocytophaga canimorsus infection should be considered in the differential diagnosis of severe febrile illnesses with thrombocytopenia, especially in individuals with animal contact.
• Early recognition and appropriate antibiotic therapy, such as amoxicillin/clavulanic acid, are crucial for favorable outcomes.
• This case underscores the potential for severe zoonotic infections from seemingly minor exposures to dogs.