WASHINGTON, April 24 (Reuters) - The U.S. Centers for Disease Control and Prevention said on Friday it was too late to contain the swine flu outbreak in the United States.CDC acting director Dr. Richard Besser told reporters in a telephone briefing it was likely too late to try to contain the outbreak, by vaccinating, treating or isolating people."There are things that we see that suggest that containment is not very likely," he said.He said the U.S. cases and Mexican cases are likely the same virus. "So far the genetic elements that we have looked at are the same." But Besser said it was unclear why the virus was causing so many deaths in deaths in Mexico and such mild disease in the United States.(Reporting by Maggie Fox, editing by Patricia Zengerle)
According to Mexican health officials, an epidemic of swine flu has killed at least 68 people and infected a further one thousand inside the country.

Mexican health minister José Ángel Córdova said that the casualty rate appeared to be slowing down, and that there would be no plans to block off Mexican borders. “We’re dealing with a new flu virus that constitutes a respiratory epidemic that so far is controllable,” Córdova stated. He said that the disease had mutated from pigs and was transferred to humans at some point.

Museums and schools for seven million students near Mexico's capital were closed down in an effort to curb the epidemic, and the government has encouraged people with symptoms of the disease to take leave from work.

The outbreak has spread north to the United States, and US health authorities have reported that eight people were diagnosed with swine flu in Texas and California. However, these people have recovered.

“We are worried. We don’t know if this will lead to the next pandemic, but we will be monitoring it and taking it seriously,”  said Dr. Richard Besser, the acting head of the Centers for Disease Control and Prevention (CDC). Dr. Besser suggested "containment is not very likely" in a telephone briefing on Friday.

Tests conducted by the World Health Organisation (WHO) found that the virus from a dozen patients was genetically similar to a new outbreak of swine flu, designated as H1N1.