The new strain of Influenza A/H1N1 continued to spread around the world on Sunday as the disease has been confirmed in more than 4,150 people in 29 countries.

Canada and Costa Rica confirmed their first fatality case on Saturday, bringing to four the number of countries which have reported confirmed human death cases.

In Costa Rica, a 53-year-old man became the first fatal victim of the A/H1N1 flu. In the Canadian province of Alberta, local health authorities said the A/H1N1 strain caused the death of a woman in her 30s who died late April.

But health officials noted that both victims and the two deaths in the U.S. were suffering from other health problems when they were infected with the disease.

In Tokyo, a high school teacher and two teenage students tested positive for the disease at the airport after returning from a school trip to Canada.

Japanese health authorities have been tracking passengers who arrived on the same plane while Health and Welfare Minister Yoichi Masuzoe acknowledged it would be difficult to trace all those who came into contact with the three infected.

Australia's Queensland health authorities said Saturday that an Australian woman arriving in Brisbane from Los Angeles tested "weak positive" for the H1N1 virus, becoming the country's first case.

Federal Health Minister Nicola Roxon said the woman first noticed her symptoms while traveling in the U.S., but she had already recovered.

Also on Saturday, New Zealand, the first country in the Asia-Pacific region to confirm A/H1N1 flu cases, reported two more on Saturday for a total of seven.

U.S. Health officials warned that the virus has moved into the southern hemisphere, where influenza season is just beginning, and could mix with circulating seasonal flu viruses or the H5N1 avian influenza virus to create new strains.

The U.S. Centers for Disease Control and Prevention on Saturday reported 2,254 confirmed U.S. cases of the virus with 104 people being hospitalized, overtaking Mexico, epicenter of the outbreak, where at least 1,578 have been confirmed to be infected with the virus.

Mexico on Saturday raised the confirmed death toll to 48. Schools in the capital Mexico City will resume classes on Monday while the states of Jalisco and Guerrero have extended the closure of schools for another week after suspected flu deaths.

(Xinhua News Agency May 10, 2009)