Which of the following is NOT an example of a virus?

Botulism is caused by a toxin produced by the bacterium Clostridium botulinum, not a virus. This differentiates it from the other choices listed, which are all viral infections. Marburg, Dengue fever, and Ebola all stem from viral pathogens, characterized by their ability to replicate inside host cells, leading to illness through various mechanisms associated with viral infection.

Understanding the nature of pathogens is fundamental in fields such as infectious disease control and public health. Viruses generally require a host for replication, while bacteria like Clostridium botulinum can exist independently in the environment, differentiating the nature of the diseases they cause.