MMWR: Swine-Origin Influenza A (H1N1) Virus Infections in a School — New York City, April 2009
2009
On April 24, 2009, CDC reported eight confirmed cases of swine-origin influenza A (H1N1) virus (S-OIV) infection in Texas and California. The strain identified in U.S. patients was confirmed by CDC as genetically similar to viruses subsequently isolated from patients in Mexico. Source: cdc.gov

