Final answer:
Rare strains kill hosts more quickly than common strains.
Step-by-step explanation:
In the context of infectious diseases, this statement suggests that less common or rare strains of a pathogen may be more virulent or have a higher lethality, causing a quicker and more severe course of illness in the host compared to more common strains.
This phenomenon is observed in certain infectious diseases where less prevalent strains may have evolved to be more aggressive in order to overcome host defenses or outcompete other strains. However, it's important to note that the relationship between strain prevalence and virulence can vary depending on the specific pathogen and host factors.