Two people admitted to a Scottish hospital after returning from Mexico have been confirmed as the first British cases of swine flu.Scottish Health Secretary Nicola Sturgeon says the pair are recovering in Monklands hospital
She said seven other people who had been in contact with them were now displaying mild symptoms.
As many as 149 people in Mexico are suspected to have died after contracting swine flu.
It is caused by the H1N1 strain associated with pigs crossing over to the human population.
The BBC has learned that the infected Scottish couple are from the Polmont area of Falkirk.
The pair, who had been travelling together, returned from Mexico on Tuesday 21 April.
I would reiterate that the threat to the public remains low
Scottish Health Secretary
However, they had not presented at the doctors until Saturday.
Since then they have been undergoing tests at Monklands Hospital in Airdrie, North Lanarkshire.
Ms Sturgeon said there had been a gap of several days before those people who had been in contact with them could be given anti-viral treatment.
She said that out of the 22 people who had been identified as being in contact with the infected patients, seven had developed "mild symptoms".
This had not been confirmed as swine flu.
These people were receiving drugs at home, not in hospital, she said.
Ms Sturgeon added: "With the contacts who are now showing, all be it mild symptoms, their immediate contacts can be given anti-virals much more quickly so it does increase our ability to stem that flow."
She stated: "We're dealing with a virus that we hope doesn't, but could have much wider impact.
"But at the moment we're focused on people we know have had contact with the two confirmed patients and we're trying to put as much of a ring around them as possible."
Antiviral drugs have been effective in treating swine flu outside Mexico
Ms Sturgeon refused to give any details of the two patients who have been infected, but she said they were "not particularly ill".
The health secretary said: "I would reiterate that the threat to the public remains low and that the precautionary actions we have taken over the last two days have been important in allowing us to respond appropriately and give us the best prospect of disrupting the spread of the virus.
"However, this is a developing situation which we continue to monitor very closely, in conjunction with our colleagues in other parts of the UK and the World Health Organisation."
Ms Sturgeon said the Scottish Government was well prepared for any pandemic flu and had significant stockpiles of the antiviral drugs - Tamiflu and Relenza - which have been effective in treating swine flu in other countries.
On top of the deaths in Mexico, there have been 40 cases of swine flu reported in the US and six in Canada and one in Spain. There are also suspected cases in New Zealand, France, Israel and Australia.
However no-one has died outside Mexico.
Ms Sturgeon said: "We remain very encouraged by the fact that outside Mexico everyone who has contracted swine flu has experienced mild symptoms only."
UK Health Secretary Alan Johnson said 17 of 25 possible cases reported in the UK were being investigated.
Mr Johnson told the Commons eight of the 25 cases had proved negative.