The White House has already requested a billion and a half dollars to fight the growing outbreak.
Meanwhile, Mexico's Health Minister Jose Angel Cordova said on Tuesday night that more than 1,300 people were in hospitals, some of them "seriously" ill, out of a total of around 2,500 suspected cases of the virus.
"In the last few days there has been a decline (in cases)," Cordova told a news conference. "The death figures have remained more or less stable."
Cordova said the victims ranged from children through young adults and middle-aged people to the elderly, a different pattern to the common seasonal flu that mainly kills the elderly and already unwell people.
British Prime Minister Gordon Brown said today three more cases of the flu have been confirmed, for a total of five known cases.
In the U.S., the outbreak has escalated, with the total number of cases confirmed in the United States jumping to 91 and spreading to more states, health officials said. Experts expect that figure to keep rising.
"I do expect more cases and expect more states to be affected," Rear Admiral Dr. Anne Schuchat, interim deputy director for the Centers for Disease Control and Prevention's science and public health program, told a Senate hearing today. "I think we need to be prepared that even if it starts to look a little better, it may get a little worse."
The CDC has been working to distribute test kits for the virus, identified only last week in the country. Without the kits, confirming infection can take days.
To fight the epidemic, the Obama administration is asking Congress for $1.5 billion. White House press secretary Robert Gibbs said the president was requesting the funds "out of an abundance of caution" to "enhance our nation's capability to respond to the potential spread of this outbreak."
The government's request underscores how seriously U.S. officials are treating the threat. Alarmed by the growing number of swine flu cases and the possibility that a California man may have died from the disease, Gov. Arnold Schwarzenegger declared a state of emergency today to help deal with the outbreak.
California has confirmed 15 cases of swine flu, and Tuesday it was investigating whether one man may have died as a result of the virus. According to Los Angeles County public health official Jonathan Fielding, the case is still being investigated. If it is confirmed, it would be the second death in the U.S. attributed to the illness.
Besser declined to comment on the California investigation, but said, "I fully expect we will see deaths from this infection."
Florida has reported an incidence of swine flu today, and Indiana health officials confirmed this afternoon that a student at Notre Dame has swine flu. These developments bring to seven the number of states where the infections are being investigated.
In Orlando, Fla., the chief medical officer at Florida Hospital Loran Hauck indicated the flu has spread to a tourist who visiting the crowded Disney World.
"A case was diagnosed here in Orlando today on a tourist from Mexico who came to Disney attractions two days ago to visit," Hauck wrote in the email. Florida health officials have not confirmed that the tourist was stricken with swine flu.
The outbreak is expected to keep growing because the CDC said today the new count includes "a number of hospitalizations."