The big worry - as yet unrealised - is that the flu virus could mutate into an easily transmissible organism within the human population, triggering a pandemic.

It's incredibly adaptable to any species or form of known life, and easily transmissible.

These strains are easily transmissible (passing between and colonising both patients and hospital staff) and can cause serious disease.

The virus, however, has not been found to be easily transmissible from person to person.

Such cases would suggest that the disease had become more easily transmissible.

They have come to emphasize the translation of information (easily transmissible via new media) into physical spaces, offering a more communal, reality-grounded experience than computer monitors alone allow for.

The H5N1 virus may mutate or combine with another human flu virus to become easily transmissible among people.

H5N1 is easily transmissible between birds, facilitating a potential global spread of H5N1.

But if an avian flu mutated enough to become easily transmissible among humans, almost no one would have a natural immunity.

If it did become easily transmissible, some experts say it could kill tens of millions of people.