SAO PAULO - Brazil declared an end to its public health emergency over the Zika virus on Thursday, 18 months after a surge in cases drew headlines around the world.

The mosquito-borne virus wasn't considered a major health threat until the 2015 outbreak revealed that Zika can lead to severe birth defects. One of those defects, microcephaly, causes babies to be born with skulls much smaller than expected.

Photos of babies with the defect spread panic around the Western Hemisphere and around the globe, as the virus was reported in dozens of countries. Many would-be travelers canceled their trips to Zika-infected places. The Centers for Disease Control and Prevention and others recommended that women who were pregnant shouldn't travel to affected areas. The concern spread even more widely when health officials said it could also be transmitted through sexual contact with an infected person.