The number of swine flu-related deaths outside of Mexico rose after the U.S. reported its third fatality and Costa Rica its first, but both men also suffered from complicating illnesses, health officials said, AP reported.
In Mexico, the center of the outbreak where 48 people with swine flu have died, most of the victims have been adults aged 20 to 49, and many had no reported complicating factors.
Elsewhere, five others have died while infected with the virus, including the two fatalities reported Saturday, but each of them had additional health issues. People with chronic illnesses usually are at greatest risk for severe problems from flu, along with the elderly and young children.
In Washington state, health officials said a man in his 30s had underlying heart conditions and viral pneumonia when he died Thursday from what appeared to be complications from swine flu. The state Department of Health said in a release Saturday that swine flu was considered a factor in his death.
"We're working with local and federal partners to track this outbreak," said Washington State Secretary of Health Mary Selecky. "We urge people to take this outbreak, and the seasonal flu we see every year, very seriously."
The death of a 53-year-old man in Costa Rica on Saturday was the first involving swine flu outside of North America. He also suffered from diabetes and chronic lung disease, the Health Ministry said.
Previously, U.S. authorities reported swine flu deaths of a toddler with a heart defect and a woman with rheumatoid arthritis, and Canadian officials said the woman who died there also had other health problems but gave no details.
The Costa Rican fatality was one of eight swine flu cases in the country confirmed by the U.S. Centers for Disease Control and Prevention, Health Minister Maria Luisa Avila told The Associated Press.
Avila said officials had been unable to determine how the Costa Rican patients became infected, but she said he had not recently traveled abroad. Many flu sufferers in other nations have been linked to recent trips to the United States or Mexico.
Mexico, which raised its count of confirmed cases to 1,626 based on tests of earlier patients, continued to gradually lift a nationwide shutdown of schools, businesses, churches and soccer stadiums.
But an upswing in suspected - though not confirmed - cases in parts of Mexico prompted authorities in at least six of the country's 31 states to delay plans to let primary school students return to class on Monday after a two-week break.
"It has been very stable ... except for those states," Health Department spokesman Carlos Olmos said, referring to states in central and southern Mexico.
Mexican health authorities released a breakdown of the first 45 of the country's 48 flu deaths that showed that 84 percent of the victims were between the ages of 20 and 54. Only 2.2 percent were immune-depressed, and none had a previous history of respiratory disease.
In Canada, officials said almost 500 hogs quarantined on an Alberta farm after being diagnosed with swine flu had been killed because animals were becoming overcrowded since the facility was barred from shipping any to market.
"They were not culled for being sick. They were culled because of animal welfare concerns," Dr. Gerald Hauer, the province's chief veterinarian, told reporters. He said about 1,700 pigs remained on the farm.