Latest research has shown that flu can be transmitted before the appearance of symptoms. This research was conducted at Imperial College London and was published in the open access journal PLoS ONE.
This research was done on animal models (ferrets) as yet and if it true for humans then it means people are spreading flu before they know that they are infected from influenza virus. All the previous research has shown that mostly transmission occurs after the onset of symptoms but some can also transmit earlier.
Research has suggested that certain viral particles are expelled outside via normal breathing which acts as the source of transmission.
Lead researcher Professor Wendy Barclay, from Imperial College London, 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.
“It also means that doctors and nurses who don’t get the flu jab are putting their patients at risk because they might pass on an infection when they don’t know they’re infected.”
The infected Ferrets were place close to the healthy animals for short period of time and it was observed that transmission of flu occur even before the appearance of first symptom (fever) in Ferrets. The virus was passed to the animals place closer and adjacent to the infected Ferrets.
The researcher further suggested that flue was transmitted to other animals just within 24 hours from infected Ferrets. The frequency of transmission was reduced significantly after five and six days.
Co-author Dr Kim Roberts, now based at Trinity College Dublin, said: “Ferrets are the best model available for studying flu transmission, but we have to be cautious about interpreting the results in humans.
“We only used a small number of animals in the study, so we can’t say what proportion of transmission happens before symptoms occur. It probably varies depending on the flu strain.”