Dogs are beloved companions, but they can also be vectors for a wide spectrum of infections that go well beyond the classic bite wound. A clinical review highlights how scratches, saliva contact with broken skin or mucous membranes, urine exposure, and even indirect contact with contaminated objects can all transmit disease — ranging from viral and bacterial to fungal and parasitic.

Among the most serious threats is rabies, which is nearly always fatal once symptoms appear and requires immediate postexposure prophylaxis after any significant exposure. Capnocytophaga canimorsus, part of normal dog oral flora, can rapidly progress to fulminant sepsis — even in otherwise healthy individuals. Pasteurella multocida, commonly found in bite wounds, can cause local infections that escalate to septic arthritis or osteomyelitis if untreated. Beyond bacteria, dogs can also spread leptospirosis via urine, fungal infections like Microsporum canis, and parasites such as Echinococcus and Toxocara canis. Dogs may even harbor multidrug-resistant bacteria like MRSA.

Key Takeaways:

• Always take a structured exposure history — bite, scratch, saliva contact, travel history, and vaccination status all matter
• After any bite, prioritize wound care, tetanus booster assessment, and rabies exposure evaluation
• High-risk wounds (hand injuries, deep punctures, immunocompromised patients) warrant prophylactic antibiotics
• Amoxicillin/clavulanic acid is first-line for most infected bite wounds

Why it matters: As pet ownership rises globally, dog-associated zoonoses are an underappreciated clinical challenge. Recognizing the full range of transmission routes and pathogens can be life-saving, especially for immunocompromised or asplenic patients.