In biological defense, what does the term "host range" refer to?

The term "host range" is defined as the variety of species that a particular pathogen or infectious agent can infect. This characteristic is crucial in understanding how diseases spread among different organisms and helps determine the potential impact of a biological threat on public health and ecosystems.

Understanding host range is important for biological defense because it informs strategies for monitoring and preventing outbreaks, as well as developing vaccines and treatments. Pathogens with a broad host range can affect multiple species, including humans, livestock, and wildlife, increasing the likelihood of transmission and making containment efforts more challenging.

The other options refer to separate concepts: geographical distribution relates to where a pathogen is found, the number of cases pertains to epidemiological data, and symptom severity describes the clinical manifestations of an infection, none of which encompass the definition of host range.