A further three cases of swine flu have been detected in Ireland, bringing to seven the number of confirmed sufferers.

The latest Irish cases were confirmed as the World Health Organisation said the spread of the flu strain in Britain, Spain, Australia, Chile and Japan has moved the world closer to the top pandemic alert, level six.

The individuals who have tested positive for the virus include a man and a child from the west of Ireland and a woman from the eastern region. All of them had recently returned from New York, according to the Department of Health. The new cases are unconnected with the previous Irish sufferers.

The three are being treated at home for the influenza strain, and precautions to protect public health are being taken.

“We have expected further cases so this does not come as a surprise,” said Dr Tony Holohan, chief medical officer at the Department of Health.