DAMIAN J. TROISE AP Business Writer NEW YORK (AP) — Gilead Sciences Inc. and other companies with a stake in flu treatments will likely see revenue boosts if the swine flu outbreak continues to spread, several Wall Street analysts said Monday. The swine flu outbreak has heightened fears of a global pandemic. The bug is already suspected in more than 100 deaths in Mexico, with more than 1,400 cases, mostly in Mexico City. It has spread to the U.S., where it caused the shutdown of a New York school. Cases are being investigated in Spain and Canada. The U.S. government declared a health emergency and released 25 percent of Tamiflu and Relenza treatment courses from the national stockpile to make sure health care providers are ready for any escalation in cases. Tamiflu, which is an oral treatment, was developed by Gilead, which receives royalties from the drug's maker, Switzerland-based Roche. Tamiflu is sold in Japan through a company mostly owned by Roche, while in India, Cipla makes a generic version. Gilead shares rose $2.30, or 5 percent, to $48.02 in premarket trading. Relenza, an inhaled drug, is made by GlaxoSmithKline. Both drugs are antiviral medications and are most effective when taken soon after the onset of symptoms. The companies have confirmed that the swine flu strain is sensitive to their drugs. "Assuming the stockpile will be replenished, we estimate this represents up to $388 million worth of Tamiflu sales or $70 million in royalties for Gilead," Somaiya said in a note to investors. "However, if the outbreak escalates into a pandemic we expect further upside driven by retail demand for the drug." Lazard Capital Markets analyst Joel Sendek also said Gilead is a likely beneficiary of the swine flu outbreak, with increased sales of Tamiflu. Meanwhile, Rodman & Renshaw analyst Elemer Piros, meanwhile, said Rockville, Md.-based biotech company Novavax Inc. could see a benefit from the outbreak, as its technology is one of the fastest methods for creating a vaccine. "If the infection escalates and a government body decides to stockpile vaccine, we believe that Novavax is well positioned to capitalize on this opportunity with its recombinant vaccine technology," Piros said in a note to investors.