Cross-species transmission is uncommon but documented.
- Animal ➜ Human: B. bronchiseptica can infect immunocompromised people, causing bronchitis or pneumonia. Routine hand-washing and pet vaccination reduce this risk.
- Human ➜ Animal: Classic B. pertussis rarely infects dogs or cats, and such cases have no epidemiological impact.
Standard biosecurity—vaccination, surface disinfection, and isolation of coughing pets—keeps zoonotic events exceptionally rare.