( CNN ) -- Arizona reported its fourth death from the H1N1 virus , commonly known as swine flu , health officials said Wednesday . The H1N1 strain is relatively mild , but it 's being closely watched for mutations that might become severe . The victim was the second child in the Pima County area to die of flu complications , health officials said . The age of child who died Wednesday was not released , but the patient 's health was `` medically compromised . '' Earlier , officials in Cook County , Illinois , recorded their second death from H1N1 . The latest victim , from suburban Chicago , died within the past couple of days and had `` significant underlying medical conditions , '' said spokeswoman Kelly Jakubek . The first fatality occurred in a Chicago resident over the weekend . That victim also had underlying medical conditions , Jakubek said . Citing family privacy , she would not reveal the victims ' ages or genders . By late Wednesday , the most-recent deaths in Arizona and Illinois had not been included in the Centers for Disease Control and Prevention 's official tally of 11 U.S. deaths from the disease . They are in Arizona ( three ) , Missouri ( one ) , New York ( two ) , Texas ( three ) , Utah ( one ) and Washington ( one ) . Nor did the CDC 's count include two more deaths reported by the New York City Department of Health and Hygiene . The World Health Organization has counted 14,557 cases of H1N1 -- 96 of them fatal -- in 48 countries . Seasonal flu typically kills 36,000 Americans in any given year , though such cases usually have tapered off by this time of year , according to the CDC . 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 .
Arizona reports its fourth death linked to H1N1 virus , also known as swine flu . Officials in Cook County , Illinois , report their second flu death . Latest two deaths not in CDC 's official tally of 11 swine-flu deaths in U.S. World Health Organization has counted 14,557 cases of H1N1 -- 96 of them fatal .