he number of measles cases in the Western Hemisphere fell by 99 percent over the last decade, thanks to an aggressive vaccination campaign led by the Pan American Health Organization, according to an article in The Morbidity and Mortality Weekly Report from the Centers for Disease Control and Prevention in Atlanta.

The virus that causes the disease remains common in Haiti and the Dominican Republic, but the number of cases in the 41 countries that report to the Pan American organization fell from about 250,000 in 1990 to 1,754 in 2000. And only 423 confirmed cases had been reported for 2001 through mid-November, the article said.

Those figures include 86 cases in the United States in 2000 and 95 cases in 2001, most caused by visitors from other countries, said Dr. Mark Papania of the disease centers.

Eradicating the disease in the Americas will require increased efforts at both vaccination and surveillance, according to an editorial that accompanied the C.D.C. report. Stemming outbreaks and reducing disease levels in high-risk areas require door-to-door vaccination campaigns. And cases will continue to be imported from other parts of the globe, the editorial said, noting that the World Health Organization estimated that 777,000 children died of measles in 2000.

Last March, the World Health Organization and the United Nations Children's Fund announced an effort to cut measles deaths in half by 2005.