SAN JOSE, May 10, 2009 (AFP) - The death toll from swine flu has topped 50 as Costa Rica reported its first fatality from the virus and Japan and Norway joined a growing list of nations with confirmed cases.
Costa Rican Health Minister Maria Luisa Avila said the country's first victim was a 53-year-old man who died on Saturday after more than a week in a hospital in the capital San Jose.
The man had been suffering from other health problems, including diabetes and a chronic pulmonary condition. Eight other Costa Ricans have contracted A(H1N1) influenza, as the virus is officially known, Avila said.
The United States meanwhile confirmed a third fatality in the northwestern state of Washington as officials said the disease posed a serious problem.
State health officials said in a statement that a man in his 30s with an underlying heart condition had died last week with what appeared to be complications from the swine flu virus.
It was the first US death from swine flu reported outside the state of Texas bordering Mexico -- the epicentre of the global epidemic, where nearly all of the swine flu deaths so far have been recorded.
"Our assessment is that transmission here in the US is ongoing, that this is a very transmissible virus, similar to the seasonal influenza viruses," said Anne Schuchat of the US Centers for Disease Control and Prevention (CDC).
In Tokyo, a high school student who recently returned from North America has tested positive for swine flu in Japan's fourth confirmed case of the virus, a government official said.
The Japanese teenager was among 49 passengers who were quarantined near Tokyo's Narita International Airport following confirmation of Japan's first three cases of the A(H1N1) influenza virus Saturday.
Earlier, the health ministry said a teacher and two of the student's schoolmates, who had been on a trip to Canada, tested positive for the virus.
The other passengers, whose nationalities were not released by authorities, arrived in Tokyo from the US city of Detroit on Friday aboard the same flight as the school party.
"The four infected people have received medical treatment in hospital but we have heard that they are not in extremely bad condition," said Yutaka Ohno, a health ministry spokesman.
In Norway, health officials announced the country's first two confirmed swine flu cases, both young adults who had recently returned from Mexico.
There have now been 48 deaths recorded in Mexico along with three US deaths and one each in Canada and Costa Rica. The World Health Organization has still to confirm three of the Mexican fatalities and the latest one from Costa Rica.
The United States has overtaken Mexico as the country with the highest number of cases.
The United States now has 2,254 confirmed cases with 104 people hospitalized; Mexico has recorded 1,626 cases including its 48 deaths, and done 5,580 tests.
Cases were confirmed in 44 of the 50 US states and the capital Washington. Health authorities were now focusing on the characteristics of the new virus and on developing a vaccine, Schuchat said.
Swine flu has now been reported in a total of 31 nations and the latest WHO figures -- which do not include new cases in Costa Rica, Japan, Mexico, Norway, Spain and the United States -- put the total number of infected at 3,440.
Canada has the world's third highest number of swine flu infections, with 281 cases, and on Friday reported its first death.
The sharp increase in cases from WHO's Friday count of 2,500 cases reflected the doubling of confirmed cases in the United States.
Mexico gradually returned to normal life this week, reopening tourist sites, Mexico City eateries, theaters and cinemas after a shutdown of more than a week. Universities and high schools reopened on Thursday and primary schools were due to open on Monday.
US President Barack Obama warned the nation on Friday that it was not out of the woods yet, as across the northern border, a woman in western Alberta province became the first person in Canada to succumb to the disease.
"We are seeing that the virus may not have been as virulent as we at first feared," Obama said at a Spanish-language town hall-style meeting at the White House.
"But we are not out of the woods yet. We still have to take precautions."
The US president warned the autumn and winter flu season later in the year could be "even worse" and lead to a fresh spike in the number of cases.