"Deadly parasite" refers to a harmful organism that lives on or inside another organism and has the potential to cause severe harm or even death to its host. Full definition
Public health officials now believe this particular parasite is under control, but other, potentially deadly parasites pose continued health threats to both you and your dog. (fox19.com)
Make sure your dog is protected against potentially deadly parasites before you leave home. (petpeoplesplace.com)
In some parts of the world the presence of certain deadly parasites (e.g. heartworm) require that dogs receive preventive medication monthly to ensure that they are not infected. (dogchatforum.com)