The findings will help to understand the origins of infectious outbreaks and predict the likelihood of the disease spreading to other populations and geographical areas.
is a type of fungus that was previously only found in warmer climates throughout the tropics. However, since 1999 outbreaks of highly virulent strains of the fungus have been reported in the cooler climes of Canada and Northwestern USA, causing serious illness in otherwise healthy people and domestic and wild animals and proving fatal in some cases.
To try to understand how likely it is that the disease will spread further, a team of researchers in the US and UK interbred different strains of the fungus to test how easily the characteristics of these more dangerous strains can be transferred to other less harmful strains.
The results show that genes conferring traits that make the fungus more dangerous are easily passed to the offspring when the two parent strains are closely related. When the strains are distantly related to each other, the genes are much less likely to spread.