The new study, published this week in the journal Current Biology, reports that researchers were able to successfully manipulate a virus to evolve the ability to change behavior according to the number of other viruses present in a host. The research demonstrates that viruses can easily adapt their behavior to spread an infection alone or in combination with other viruses.
"Scientists are constantly searching for ways to limit the damage viruses can cause, to help reduce the impact of illnesses like winter flu and to respond to the next pandemic," said Helen Legget, lead scientist on the study and a researcher at the University of Exeter. "Our work proves that regardless of how we try to manipulate viruses, they will always switch their behaviour to serve their own purposes and kill as many cells as possible. This study involved a relatively simple virus. If it can evolve so quickly, it's reasonable to assume that a lot of other viruses and parasites can, too."
The viruses tested were only able to cooperate with other viruses that were related to them. When infecting a host, the viruses cloned themselves and then "cooperated" with the new viruses. Researchers said that when the viruses interacted with others related to them, they killed the host cell slowly so as to replicate more. When they interacted with unrelated viruses, however, the host was killed more quickly as a result of competition between virus types to out-replicate each other.