When alien species are introduced to a new location, they often bring with them new illnesses that were previously not present in the area. Pathogen overflow doesn’t just take place in areas where alien species are well established but can also happen in locations where these species’ presence in the environment is only temporary. Although we know that alien plant and animal hosts play an important role as vectors of dangerous pathogens, the role of invasive alien species (IAS) as a contributing factor to disease outbreaks throughout the world has not yet fully been addressed.