What are herpesviruses?
Herpesviruses are extremely common, infecting mammals, birds, amphibians, reptiles and fish worldwide. Some herpesviruses cause no obvious signs of ill health, while others result in severe disease. The type of disease varies with each species, so the symptoms shown by a person infected with a herpesvirus will differ from those displayed by an animal or bird.
Another problem is that herpesviruses can infect an animal and then become dormant within the host’s cells (latency). They can reactivate later, if the animal is stressed in any way, triggering disease.
For example, most of us have been infected with chicken pox as children. This is caused by a herpesvirus called varicella zoster. After we’ve recovered, many years can pass, but the virus can still reactivate when we’re adults, this time causing shingles.