First U.S. Resident Dies Of H1N1

(CBS/AP) Texas health officials have confirmed the first death of a United States resident with H1N1 virus (swine flu).

Few details have been released, but officials said the flu victim was a woman in her 30s who lived in Cameron County, along the U.S.-Mexico border, and had other, chronic health problems.

The Texas Department of State Health Services said Tuesday that she died earlier this week.

Last week, a boy from Mexico City died at a Houston hospital, marking the first swine flu death in the United States.

Meanwhile, U.S. health officials are no longer recommending that schools close because of the H1N1 virus.

The government last week advised schools to shut down for about two weeks if there were suspected cases of swine flu. Hundreds of schools around the country have followed that guidance and closed schools.

Health and Human Services Secretary Kathleen Sebelius said Tuesday that the swine flu virus had turned out to be milder than initially feared. She says the government is changing its advice on closing schools.

Sebelius says parents should still make sure to keep sick children at home.

The number of confirmed swine flu cases in the United States is now over 400, with hundreds more probably cases.

Also, The U.N.'s Food and Agriculture Organization has urged countries to step up surveillance on hog farms. But in the United States, that task falls to the industry, not public health officials. Meat companies police their own farms to root out disease.

The effort to detect swine flu on U.S. farms gained urgency over the weekend as Canadian officials quarantined pigs infected with swine flu by a worker returning from Mexico. If the virus infects U.S. pigs, it could spread through herds kept in crowded barns and possibly threaten people.

Swine flu is a respiratory illness caused by a virus. The virus routinely causes outbreaks in pigs but doesn't usually kill many of them. Most recover.