MEXICO CITY — Mexico yesterday announced a return to "normalcy," preparing to reopen businesses and schools.

Mexico's president said HIN1 swine flu was waning at its epicenter, justifying tomorrow's end to a five-day nationwide shutdown he credited for reducing the spread of the virus.

President Felipe Calderon said universities and high schools will reopen Thursday, and younger schoolchildren should report back to school next Monday.

Schools will turn away children who appear sick. The government is spending $15 million for detergent, bleach and soap to clean buildings, in a country where 12 percent of the nearly 250,000 schools — about 30,000 — lack running water or bathrooms.

But experts inside Mexico's swine flu crisis center warned that the virus remains active throughout Mexico and could bounce back once millions return to work and school. It also may get worse north of the border.

"The bottom line is that there hasn't been time for the severe illnesses to perhaps show up in the U.S. yet," said Marc-Alain Widdowson, a medical epidemiologist from the U.S. Centers for Disease Control and Prevention.

Health Secretary Jose Cordova insisted that swine flu infections are trending downward.