The deepening swine flu outbreak forced additional school closures in the U.S. as the death toll ticked upward -- reinvigorating fears that the deadly virus continues to tighten its grip on the globe.
A 44-year-old Missouri man who was diagnosed with swine flu after traveling to Mexico last month is the latest U.S. victim of swine flu as the number of confirmed cases worldwide ballooned to 9,830 with experts predicting as many as 100,000 in the U.S. are likely infected with the deadly virus.
An autopsy on the man and further testing is necessary to determine if the virus killed him or if another underlying illness caused his death, health officials said.
In Utah, state health officials reported a 22-year-old Salt Lake City man with "chronic medical conditions" including respitory problems died Wendesday of complications associated with swine flu.
In neighboring Arizona, health officials said Wednesday a 13-year-old boy from Tucson also has died with swine flu. The teenager died Friday of complications from the flu. He had been hospitalized May 10.
The Arizona Department of Health Services, which confirmed test results, said an older sibling of the teen is hospitalized with the virus, and other family members have recovered from the flu, according to spokeswoman Patti Woodcock.
A total of 10 deaths in the U.S. are being blamed on the virus, according to the Centers for Disease Control. The CDC said 47 states and District of Columbia have a combined 5,710 confirmed and probable cases.
The number of cases around the globe soared -- with the greatest spike in Japan, which at 191 confirmed cases has more than any other country besides the U.S. and Mexico.
Swine flu spread in the country despite airport quarantines and, as in the U.S., has mostly spread among students. Japan closed more than 4,000 schools this week.
The World Health Organization said it could create five billion doses of a swine flu vaccine within the first year of production. But the group conceded it could not start production until mid-July and would fall at least one billion doses short of covering the world's 6.8 billion people.
Swine flu has been confirmed in at least 40 countries with the most cases in Mexico and the U.S. The global death toll stands at least 86 people, 74 of which are in Mexico, 10 in the U.S, one in Canada and one in Costa Rica.