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Influenza A strain H1N1

Many different subtypes of flu exist, with Influenza A and Influenza B being the most medically serious. The 2009 swine flu epidemic was caused by a new strain of Influenza A, known as subtype H1N1. (more...)

muscle strain An injury involving a stretched or torn muscle or tendon (tendons are fibrous cords of tissue that connect muscle to bone).