The Hopper virus (also known as Hoppers) could infect anything.
In humans, symptoms included wiggling of the fingers, temporary paralysis of the lower half and hallucinations of bats. It could be cured by pinching the ear of the infected, causing them to sneeze the virus out.
At Tranquility Spa, Ryan Sinclair and Bella were both infected by the virus. (TV: Orphan 55)