European mistletoe (Viscum album) as a case study for understanding the regulation of host-parasite relationships

Parasites, which live on or in a host organism to the host's detriment, have widespread ecological, evolutionary, and socioeconomic consequences. To persist, any parasite must exploit its host's resources enough to live, without killing its host before successful reproduction and transmission. In other words, damage to the host (virulence) and transmission must be moderated to avoid local parasite extinction. We are still uncovering how host-parasite systems are regulated in this way and questioning how universally such mechanisms determine the outcome for parasite and host. Understanding what drivers tip the balance towards parasite or host is key to controlling parasites which are important to society. Such control is as essential as ever given the continued burden of disease we face.