The worldwide confirmed A/H1N1 cases have reached around 5,914 as two more countries in Asia and Europe reported their first known cases on Tuesday.
Thailand and Finland reported two cases each after Cuba earlier confirmed its first case in a Mexican student in Havana, bringing the total number of countries with confirmed cases to 33.
In the United States, which has surpassed Mexico with most known cases, Tuesday reported that a total of 3,009 have tested positive of the virus in 45 of its 50 states, with three deaths.
The number of confirmed cases on Monday was 2,600 in 44 states, according to the U.S. Centers for Disease Control and Prevention (CDC).
The increase showed that the ongoing outbreak of A/H1N1 influenza continues to expand in the United States. CDC officials have said they expect the A/H1N1 flu to spread to all 50 states, to cause severe disease and more deaths.
The Mexican government on Tuesday raised the death toll from the new influenza A/H1N1 to 58, adding two, and put the number of confirmed cases of the novel flu to 2,282, up from 2,059 on Monday.
Nurseries and primary and secondary schools reopened for the first day on Monday after a more-than-two-week suspension. At a morning press conference Tuesday, Mexico's health minister, Jose Angel Cordova Villalobos, said that sanitary cordons had identified 100,000 children with symptoms of the flu by the end of Monday.
Around half of the children were well enough to attend classes, but were taught separately. The remainder were sent home.
Meanwhile, the total confirmed A/H1N1 flu cases in Canada rose to 358 on Tuesday, with 28 new cases added during the day, according to the latest figures from the Public Health Agency of Canada on Tuesday afternoon.
Up to now, 10 out of Canada's 13 provinces and territories have reported infections. Most of the Canadian cases have been mild. There has been one death linked to the virus.
In Latin America, several countries reported increases in confirmed cases of A/H1N1 flu. The Panamanian Health Ministry said the confirmed cases in the country has risen to 29, including 11 confirmed on Tuesday.
Authorities said most of the new cases were patients between 7 and 12 years old, and seven cases were related to infections at schools.
The Colombian government confirmed on the day three new cases, bringing the total number of A/H1N1 flu cases in the country to six.
"The three new positive cases are of people from Casanare between 17 and 26 years old, who traveled to Florida (in the United States), and when coming back they had symptoms so they went to the doctor," Cardona noted.
The World Health Organization (WHO) on Monday issued preliminary observations about A/H1N1 flu, revealing new features of the virus including its tendencies to attack young people.
Though cases have been confirmed in all age groups, from infants to the elderly, the youth of patients with severe or lethal infections is a striking feature of these early outbreaks, said the WHO.
The WHO says up to 2 billion people could be infected if the outbreak eventually turns into pandemic. However, Dr. Keiji Fukuda, WHO's acting assistant director-general for health security and environment, says it's still too early to tell how widespread or severe the outbreak will become.