A flu outbreak killing 70 million people worldwide may cause global economic losses of as much as $2 trillion, a World Bank official said. A slump in tourism, transportation and retail sales, as well as workplace absenteeism and lower productivity, may cause the world economy to shrink by 3.1 percent, said Milan Brahmbhatt, a lead adviser in the East Asia region, citing a study by the Washington-based World Bank. The study predicted a surge in corporate bankruptcies in companies with a high level of debt to equity, such as airlines. “It goes almost without saying that these broad scenarios are not meant to be forecasts,'' Brahmbhatt said in a speech prepared for the First International Conference on Avian Influenza in Humans, which starts today in Paris. “They are only exercises to help think through the various channels of impact and possible orders of magnitude.'' The Bank, which funds projects to alleviate poverty, is working with developing countries to improve hospitals and laboratories to bolster disease surveillance and management of bird flu. Human fatalities from the H5N1 avian influenza strain have almost tripled this year, providing more chances for the virus to mutate into a lethal pandemic form. Since January at least 54 people have died from H5N1 as the virus spread in wild birds and domestic poultry across Asia, Europe and Africa. That compares with 19 fatalities in the first six months of 2005. In the past three years, at least 130 of the 228 people known to have been infected with H5N1 have died, according to the World Health Organization. “As these outbreaks continue and spread to new regions, they also increase the probability of a second stage, with human-to-human transmission and a global influenza pandemic, with enormously greater costs on a world scale,'' Brahmbhatt said. A pandemic can start when a novel influenza A-type virus, to which almost no one has natural immunity, emerges and begins spreading. Experts believe that a pandemic in 1918, which may have killed as many as 50 million people, began when an avian flu virus jumped to people from birds. The most immediate and largest economic impact of a pandemic might arise from the uncoordinated efforts of people to avoid becoming infected, not from actual death or sickness, according to Brahmbhatt.