With flu season approaching, experts are worried about an old strain. Scientists at the University of Florida’s Emerging Pathogens Institute don’t expect the old strain of H1N1 to return as a threat, but they are concerned about what the current strain of H1N1 might learn from the old one, because of key enzymes both strains share. The older version is resistant to Tamiflu, a critical anti-viral drug used both to prevent and reduce the severity of influenza. UF bio-statistics researcher Ira Longini says the flu is not treatable by any over-the-counter drugs, and the best thing to do is get an annual flu shot. He says the new strain could be even more difficult to battle than the old one.