After a long struggle, Sri Lanka, the large island nation southeast of India, was declared free of malaria last week by the World Health Organization. It has been more than three years since the last case.

“This is a big success story,” said Dr. Pedro L. Alonso, the director of the W.H.O.’s global malaria program. “And it’s an example for other countries.”

Sri Lanka almost succeeded in eliminating malaria 50 years ago, but its huge effort fell apart. The country became the example most frequently cited by malariologists to show how defeat could be pried from the jaws of victory.

Through the 1940s, Sri Lanka routinely had a million cases of malaria a year. Then officials began an intensive public health campaign, relying on DDT to kill mosquitoes and chloroquine to cure the disease. By 1963, the annual caseload had fallen to a mere 17.