Mexico's emergence from a national shutdown hit snags as some high schools were not cleaned in time to open and students returned to class in others without swine flu checkups. Cases of the virus popped up in two more Latin America countries.

Despite the hitches, Mexico pressed ahead with its return to normal life as workers disinfected day care centers and kindergartens in preparation for their reopening on Monday. Authorities were to pass out antiseptic hand gel to all of the capital's 5,000 schools on Friday.

Finance Secretary Agustin Carstens announced that Mexico's economy is in a recession and could contract by 4.1 percent this year because of the swine flu and a decline in exports to the U.S.

"It is a fact that we are in recession," Carstens told foreign correspondents — marking the first time the government has acknowledged Mexico is already in a recession.

A report by the Centers for Disease Control and Prevention said America's two swine flu deaths — a toddler and a pregnant woman who both died in Texas_ each suffered from several other illnesses when they were infected with the virus.

The CDC report released by the New England Journal of Medicine said the Mexican toddler had a chronic muscle weakness called myasthenia gravis, a heart defect, a swallowing problem and lack of oxygen. The 33-year-old woman had asthma, rheumatoid arthritis, a skin condition called psoriasis and was 35 weeks pregnant.

In Geneva, the World Health Organization said based on past outbreaks, it is possible that a third of the world's population, or about 2 billion people, could become infected if this outbreak turns into a two-year pandemic. Independent experts agreed that the estimate was possible but pointed out that many would not show any symptoms.

"If we do move into a pandemic, then our expectation is that we will see a large number of people infected worldwide," WHO flu chief Keiji Fukuda said Thursday. "If you look at past pandemics, it would be a reasonable estimate to say perhaps a third of the world's population would get infected with this virus."

People with chronic illnesses are at greatest risk for severe illness from the flu, along with the elderly and young children. So far, most of those with the swine flu in the U.S. and Mexico have been young adults.

"We're still learning about what patients are most at risk," said Dr. Fatima Dawood, a CDC epidemiologist.

While Mexican officials insisted the worst was over, authorities in Brazil and Argentina confirmed their first cases of the swine flu, which has now spread to 26 countries, killed 46 people and sickened more than 2,350 worldwide. Previously, Colombia was the only South American country with a confirmed case.

Brazilian Health Minister Jose Gomes Temporao said three young adults contracted the virus in Mexico, and a fourth in Florida. Only one remains hospitalized and is reported in good condition. Argentina's first swine flu case was a man who returned from Mexico on April 25 and has already been released from hospital.

On Friday, Hong Kong prepared to lift its weeklong quarantine on the Metropark Hotel, where a Mexican traveler with swine flu stayed last week. About 280 guests and employees are being held inside the building in a measure some have denounced as overreaction.

Restaurants, movie theaters, bars and businesses across Mexico were allowed to open Thursday, and students returned to high schools and universities for the first time in two weeks. Authorities also said fans will be allowed to attend soccer games this weekend, ending a policy that had teams playing in front of empty stadiums.

Mexico's government, which raised the death toll to 44, said it was not letting its guard down and that all returning students would be checked for swine flu. It gave an additional $15 million to Mexico's 32 state governments to buy whatever is needed to disinfect classrooms and provided educators with a guide on ways to protect schools from the virus.

But at a public high school in the southern city of Oaxaca, an Associated Press reporter did not see any returning students wearing masks, and no doctors or health officials checked people at the door or distributed sanitizing gel.

Orange plastic desk chairs remained covered with grime. Classrooms were packed with as many as 50 students.

"They say they washed the floors with soap and water, but you can't tell, the classrooms smell bad," said Sandra Hurtado, a freshman.

Universities reopened in the southern state of Chiapas, but various high schools in isolated mountain communities remained closed because officials could not disinfect them in time.

All will open Monday, said state education spokesman Abel Bravo.

Officials also wanted to make sure parents, many of whom speak Tzotzil and not Spanish, were informed about swine flu and ways to deter it.

At a Tijuana high school, nurses distributed sanitizing gel and school officials patrolled halls to stop students from kissing.

The precautions irked Liliana Tornero, 17.

"I'm annoyed they put gel on our hands like we're kindergartners," she said. "I know they are just trying to take care of us, but it's too much."

Janeth Torres, an industrial engineering student, wore a mask to her university in Ciudad Juarez, but she thought the epidemic was overblown.

"In these times of crisis, what we need is to work and to not be wasting time on this foolishness," she said.

The U.S. has sent more than 400,000 doses of the antiviral drug Tamiflu to Mexico as well as 100,000 protective kits for first responders. U.S. scientists are collaborating with their Mexican counterparts to investigate the outbreak and ways to stem it.

Mexico thanked U.S. officials at a ceremony in Mexico City for their cooperation and aid during the outbreak.

"The efficiency and effectiveness with which this emergency has been handled underscores the maturity of relations between the two countries," said Rogelio Granguillhome, who oversees economic ties at the foreign relations department.

In Asia, top health officials said the region must remain vigilant over the threat of swine flu, stepping up cooperation to produce vaccines and bolstering meager anti-viral stockpiles. The virus has so far largely spared Asia. Only South Korea and Hong Kong have confirmed cases.