Arizona reports its fourth death linked to H1N1 virus , also known as swine flu . Though the H1N1 strain is considered relatively mild , public health officials have been scrutinizing its spread since it was first identified in April in Mexico because they are concerned it could mutate and become more severe . Officials in Cook County , Illinois , report their second flu death . Score: 6
Arizona reports its fourth death linked to H1N1 virus , also known as swine flu . Officials in Cook County , Illinois , report their second flu death . Score: 6