How do virulence and contagiousness differ, with an example from veterinary pathogens?

• A. Virulence is the severity of disease; contagiousness is how easily a pathogen spreads; example: canine parvovirus is highly virulent and highly contagious; Bordetella bronchiseptica is highly contagious with variable virulence.
• B. Virulence is how easily a disease spreads; contagiousness is severity.
• C. Both terms mean the same thing; no distinction.
• D. Parvovirus is non-contagious.

Answer: (A)