LAS VEGAS (AP) - Celine Dion has canceled the next five performances of her "A New Day" show and an appearance at the Billboard Music Awards because of a highly contagious respiratory infection, show producers said Wednesday.

The 38-year-old Grammy-winning singer was being treated for Mycoplasma bronchitis, a contagious bacterial infection, and has been ordered to rest during her recovery, producers said.

Performances of "A New Day" at Caesars Palace, a revue created by former Cirque du Soleil Artistic Director Franco Dragone, were canceled from Wednesday through Sunday, after which Dion was scheduled to take a holiday break from the five-show-a-week regimen.

The show will not resume until Dec. 28.

Dion also backed out of a scheduled appearance at the Billboard Music Awards in Las Vegas on Monday.

Kris Lingle, a spokesman for "A New Day," said ticket-holders would receive refunds or could book other show dates.

Dion last canceled performances in April, days ahead of her 500th show at the Las Vegas Strip hotel-casino.

The singer began a three-year, $100 million contract at Caesars in March 2003, then extended it through next year.