UNITED NATIONS (AFP) - The number of swine flu victims topped the 1,000 mark on Monday as the UNs most senior health official warned that a second wave of the virus could be far worse. As Mexico, the epicentre of the outbreak, prepared for the reopening of restaurants and businesses shuttered by the A(H1N1) virus, the number of affected countries climbed once again. Mexico raised its confirmed swine flu toll to 26 deaths on Monday, but said the epidemic appeared to be slowing. The previous toll, given late Sunday, was 22 dead and 568 infected. The sense of alarm however grew in Britain when it emerged that another seven people who had not been to Mexico had the virus. World Health Organization chief Margaret Chan told UN officials in New York that despite the continued spread it was not yet time to declare a pandemic. There are now 1,003 confirmed cases of H1N1 in 20 countries. We dont know how long we have till we move to phase six. Six indicates we are in a pandemic. We are not there yet. Mexican President Felipe Calderon said the epidemic, which has left the tourism industry on its knees, had been contained as officials pledged to re-open businesses this week and get the country up and running again. Authorities in Mexico City said restaurants would reopen on Wednesday and museums and religious centres the following day. Nightclubs, cinemas and theatres would remain closed until further notice. Experts, however, cautioned the virus was far from defeated and could yet return with a vengeance. Chan said the end of the flu season in the northern hemisphere meant that while any initial outbreak could be milder, a second wave could be more lethal, reflecting a pattern seen with the 1918 Spanish flu pandemic that killed up to 50 million people. Its re-emergence would be the biggest of all outbreaks the world has faced in the 21st century, she told the Financial Times. UN chief Ban Ki-moon echoed appeals for caution, saying at the UN talks: There is still much that is not known about this new strain and the dangers it poses. In the face of uncertainty, we must be vigilant. Such vigilance was in evidence in Britain, where health officials announced nine new cases, including seven people who had not travelled to Mexico. A school attended by five of the victims in Dulwich, London, became the fourth in Britain to be closed to prevent more infections. Diplomatic damage from the epidemic also reverberated with China denying it had discriminated against Mexican nationals after dozens were placed under quarantine over the weekend despite showing no signs of the flu. More countries are confirming cases every day with Portugal the latest to join the list, while France announced two new confirmed cases as did Italy, doubling its previous caseload. Japan tripled the number of quarantine officers at Tokyos Narita airport to try to detect cases at the start of a holiday week. In the United States, the only other country to have recorded a death from the virus, officials said 36 of the 50 states had now confirmed cases. US Health and Human Services Secretary Kathleen Sebelius agreed the real test would come when the winter flu season hits. Even if this current situation seems to be lessening, if we are cautiously optimistic, we really dont know whats going to happen when real flu season hits (together) with H1N1 virus, she told CBS television. In China, centre of the 2003 SARS outbreak, authorities have been accused of discriminating against Mexicans in a bid to keep out the virus. Although no case of swine flu has been reported on mainland China, one Mexican who stayed in a hotel in Hong Kong has tested positive. A Mexican embassy official in Beijing said nearly 70 Mexicans had been quarantined across China including in Beijing, Shanghai and the southern city of Guangzhou even though they had no flu symptoms. Some 250 recruits and personnel at an army camp in the western Swiss canton of Fribourg were also placed under quarantine after two recruits were suspected of contracting the virus. Egypt pushed ahead with a mass slaughter of the countrys quarter of a million pigs, a day after clashes erupted with protesting pig farmers.