May 25 (Bloomberg) -- Swine flu is spreading more widely than official figures indicate, with outbreaks in Europe and Asia showing it’s gained a foothold in at least three regions.

One in 20 cases is being officially reported in the U.S., meaning more than 100,000 people have probably been infected nationwide with the new H1N1 flu strain, according to the Centers for Disease Control and Prevention. In the U.K., the virus may be 300 times more widespread than health authorities have said, the Independent on Sunday reported yesterday.

Prof Oxford, of the University of London, said the virus would increase its power as it spreads and the pandemic will hit before a vaccine - to cover about 15 per cent of the population - is available in October or November.

It is currently estimated up to 50 per cent of the population may get infected by swine flu but the professor warned this might be "on the low side". He added: "The virus will be like a bushfire."

In the Dominican Republic officials confirmed nine cases of the disease, raising the country's total to 11, a day after Santo Domingo rebuffed a Russian claim that the Caribbean island was underreporting its cases in a bid to boost tourism.

We fear that in reality, the situation is very different," Gennady Onishchenko, Russia's chief sanitary inspector, had told the Interfax news agency in response to the island reporting only two cases.

On Sunday the island's Ministry of Public Health reported that of the nine new cases one had been hospitalized.

SANTIAGO (AFP) — Chilean health authorities confirmed 26 new cases of swine flu, raising the number of patients with A(H1N1) virus in the country to 276, the highest number on the continent.

The sometimes-deadly disease continued its rise across Latin America meanwhile with Argentina, Brazil, Bolivia, Peru and the Dominican Republic all reporting new cases.