Swine Flu Changes Accelerate
US - Ever since the H3N2 subtype of swine influenza virus (SIV) was identified in U.S. swine herds in 1999, the virus has continued to change, much like it has previously done in the human population.
US - Ever since the H3N2 subtype of swine influenza virus (SIV) was identified in U.S. swine herds in 1999, the virus has continued to change, much like it has previously done in the human population.
