The swine flu virus continued to spread today as the UK infection tally rose.
A fourth case of swine flu was confirmed in Scotland, health secretary Nicola Sturgeon said.
The man lives in the Ayrshire and Arran health board area and was identified yesterday as a probable case. He has no connection to the three Scottish cases which have previously been confirmed.
He is a travel-related case, having flown back from the USA to Birmingham last Monday, and then on to Glasgow airport on Thursday, by which time he was showing symptoms of the virus.
Yesterday, a six-year-old girl and the husband of a woman already diagnosed with the bug were confirmed as outbreaks. Both new cases had recently returned from Mexico.
More than 630 other people in the UK and three in Ireland are also undergoing tests for the disease.
The extra cases came as world health officials appeared to play down the virulence of the flu strain, advising that there was no evidence the swine flu virus was spreading in a sustained way outside North America.
The young girl confirmed with the bug yesterday, who is from Oxfordshire, has not been to school since arriving back in the UK and health chiefs decided against closing her school.
Professor John Newton, regional director of public health at the NHS South Central Strategic Health Authority, said she was treated and isolated soon after her return and was now making "a good recovery at home".
The other new UK case is a Merseyside man married to a woman who was confirmed as having swine flu on Friday.
NHS North West said in a statement: "Both people had recently visited Mexico together. Both are being treated at home and are described as being quite well.
"Family members and other close contacts of the couple were routinely treated with anti viral medication as a precautionary measure and they continue to be monitored."
As well as the Irish case — who officials said was under quarantine at home and recovering well — there are now 12 confirmed cases of the virus in England and three in Scotland.
People have been affected in Newcastle, Merseyside, Devon, Worcestershire, Gloucestershire, Oxfordshire, London and Central Scotland.
All those in the UK who have contracted the disease appear to be suffering mild symptoms.
On Friday the first cases in which people contracted swine flu without visiting Mexico were confirmed.
Barry Greatorex, 43, from Chipping Sodbury, in south Gloucestershire, believes he caught the virus from a colleague, who recently visited Mexico, after a brief meeting in her office.
He said she was "coughing and spluttering" during the half-hour conversation.
The woman was cleared of having the virus but is now being retested.
The other case to be announced where a person fell ill without travelling to Mexico was Graeme Pacitti, 24, from Polmont, near Falkirk, Scotland.
He contracted the disease after coming into contact with Iain Askham, who fell ill after his honeymoon in Mexico.
Meanwhile, the lead singer from band N-Dubz was being treated in a Greek hospital for a suspected case of the disease, the band's manager confirmed.
Tulisa Contostavlos (20) from north London, was undergoing tests in hospital in Athens after becoming ill on a flight to the country on Thursday.
Elsewhere, 14 possible cases of swine flu are still under investigation in Wales, health officials said today.
All of the cases involve people showing mild symptoms following travel to Mexico and the USA.
The World Health Organisation's (WHO) alert level remains at phase five of six, meaning a global outbreak is imminent but still not yet officially declared.
Dr Michael Ryan, WHO Director of Global Alert and Response, said there was "no evidence of sustained community spread outside of North America".
He also praised European nations' handling of cases and said events did not seem out of control.
There have been at least 615 confirmed cases worldwide.
Mexico has cut its suspected death toll by 75 to 101, indicating the outbreak may not be as bad as initially feared.
The confirmed death toll remains at 19 in Mexico and one other involving a 21-month old Mexican boy who had travelled to the US.
Health Secretary Alan Johnson said: "We are going to continue to monitor the situation. While we hope for the best we have to prepare for other eventualities and that is what we are doing. At the moment the policy is working very well."
Spain's number of confirmed cases of swine flu rose to 20 from 15, the country's health ministry said in a statement on its website late yesterday. Spain also has 99 cases of people suspected of having the illness.
Agencies