The United States now has 642 cases of the new H1N1 flu, with two deaths, the Centers for Disease Control and Prevention reported.
CDC officials have said they expect the new swine flu to spread to all 50 states, to cause severe disease and some deaths, although most cases have been mild.
Mexico has confirmed 42 deaths and said it was impossible to get samples from about 70 more people who died of flu-like illness recently. Globally, more than 1,600 cases have been reported in 23 countries.
A Texas woman with the flu died earlier this week, US health officials have said, in what is the second death outside of Mexico.
Officials said the woman, who was in her 30s, had other health problems. US health officials have predicted that the swine flu virus would spread and inevitably kill some people, just as seasonal flu does.
Last week a Mexican toddler visiting Texas also died.
Elsewhere, the US navy has cancelled a humanitarian mission to the South Pacific because a sailor on a transport ship contracted swine flu. Four other cases of swine flu were confirmed at the Naval Base San Diego.
The sick sailor, who is from the USS Dubuque, is being treated, and 50 other members of the 470-crew vessel are being given preventative doses as well.
The Dubuquewas scheduled to depart June 1 for a four-month voyage to Kiribati, the Marshall Islands, Samoa, the Solomon Islands and Tonga, according to a Navy statement. The ship carries preventive medicine personnel, veterinarians, medical and dental teams and engineering personnel.
Health officials said the outbreak seemed to be slowing in Mexico, the country hardest-hit by the virus, which is a mixture of swine viruses and some elements of human and bird flu. At the same time, infections were breaking out globally and are expected to spread.
Trade skirmishes over pork worsened, with some countries imposing new restrictions, despite assurances by the United Nations Food and Agriculture Organisation that pork, especially cooked pork, was safe to eat.
Agencies