Federal officials said the flu had been confirmed in four more states with 91 cases nationwide as of Wednesday.

The first confirmed death in the U.S. from swine flu was a 23-month-old Mexican child who died in Houston, officials said.

Kathy Barton, a spokeswoman for the Houston Health and Human Services Department, said Wednesday that the child had traveled with family from Mexico and was taken to a Houston hospital where the child died Monday night.

The Centers For Disease Control and Prevention confirmed the death earlier Wednesday. "Even though we've been expecting this, it is very, very sad," Dr. Richard Besser, acting chief of the Centers for Disease Control and Prevention, said Wednesday of the infant's death. "As a pediatrician and a parent, my heart goes out to the family."

President Barack Obama said Wednesday morning that Americans should know the government is doing all it can to control the virus. Obama also said schools should consider closing if the spread of the swine flu virus worsens.

Special Section: Questions And Answers About Swine Flu

Locally, a doctor at Memorial Medical Center said a few patients have come to the emergency room concerned about having some symptoms but medical providers said they did not have the swine flu.

The symptoms of swine flu are similar to regular human flu -- a fever, cough, sore throat, body aches, headache, chills and fatigue. Some people also have diarrhea and vomiting.

Medical officials said people should take commonsense precautions like covering coughs and sneezes with a tissue or sneezing into their elbow rather than their hand. People should also wash their hands frequently; if soap and water aren't available, hand gels can substitute. People should stay home if they're sick and keep children home from school if they are.

Health authorities said people who live in places where swine flu cases have been confirmed, or recently traveled to Mexico, and have flulike symptoms, should ask a doctor if they need treatment or to be tested. Allergies won't cause a fever and run-of-the-mill stomach bugs won't be accompanied by respiratory symptoms, noted Dr. Wayne Reynolds of Newport News, Va., spokesman for the American Academy of Family Physicians.