Research at Imperial College London, examining influenza transmission in ferrets, suggests that the virus can be passed on before the appearance of symptoms.
If the findings apply to humans, it means that people pass on flu to others before they know they’re infected, making it very difficult to contain epidemics. The research was supported by the National Institute for Health Research (NIHR) Imperial Biomedical Research Centre and the study was published in the open access journal PLOS ONE.