BOGOTÁ, Colombia — Health officials here on Monday declared an end to the Zika epidemic in Colombia, the first time a South American country had turned the tide on the disease, they said.

The Zika virus, which causes an illness related to dengue and is spread by mosquitoes, has infected roughly 100,000 Colombians and is linked to more than 20 cases of microcephaly, a birth defect that causes babies to be born with abnormally small heads.

While health officials said the number of new infections had decreased to 600 new cases a week, they added that they still expected a limited number of new cases in the coming months as the disease wound down.

“The period the disease will remain local still hasn’t been determined,” Fernando Ruiz Gómez, the deputy health minister, said at a news conference. “There may eventually be extended outbreaks.”