A seventh case of swine flu was confirmed in Israel on Friday when a 58-year-old Elkana woman who returned from the US at the beginning of the week was found to have contracted the virus, according to the results of tests carried out there. The woman had not been hospitalized, but has since recovered. The Health Ministry said anyone who was on the woman's flight from New York on Sunday - El Al 008 - and was feeling unwell should go straight to the emergency room. Meanwhile, in Mexico, where 44 people have have died from the virus, 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. Despite the hitches, the country 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. A report by the Centers for Disease Control and Prevention said the United States' 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 was 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. 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.