Real world article
(written from a production point of view)
According to the script for Star Trek IV: The Voyage Home, a bio-sterilization capsule was a type of electrical containment device used for pathogens.
During the Whale Probe crisis of 2286, the starship USS Shepard was transporting the Vegan D virus in these capsules when the ship ran afoul of the probe. The encounter resulted in these capsules failing, and fifteen crew members dying from the virus.