Flu can be fatal, especially in older adults, and it is important that vulnerable individuals are vaccinated and the disease is contained. However, a new study claims that stopping the spread of flu may be more complicated than previously thought. Researchers at Imperial College London have found that influenza may be passed on to others before symptoms even appear in the original host. Although this was only observed in a ferret model, if the same is true in humans it will make containing epidemics extremely complicated. During the study, animals with flu were put in contact with uninfected ferrets for short periods of time at different stages of infection. It was found that transmission occurred prior to the first symptom developing. What's more, the infection travelled not just to ferrets in the same cage as their infected contemporaries, but to those in adjacent cages. Professor Wendy Barclay, the study's lead author, said: "This result has important implications for pandemic planning strategies. It means that the spread of flu is very difficult to control, even with self-diagnosis and measures such as temperature screens at airports." Find the nearest Barchester care home.