'Here to stay'
Brazil has been the country hit hardest by Zika, with 1.5 million people infected and more than 2,000 babies born with brain damage.
The disease, which originated in Africa, has swept Latin America and the Caribbean since it was first detected in Brazil last year.
"Traveler's Zika" -- cases brought back by people who spent time in affected countries -- also reached Europe and the United States.
Then, last July, US health authorities announced that locally transmittedZika cases had been detected in Florida.
Meanwhile, warnings were emerging that tropical mosquitoes were not the only vector for the disease.
In February 2016, the United States reported a case of sexual transmission in Texas. Dozens more followed.
Recent research indicates the virus could also be spread through tears or sweat.
Melo warned health authorities not to take their eyes off the epidemic, even though the number of cases has diminished as mosquito populations have declined during the southern hemisphere winter.
"We need to use this moment of calm, after the explosion of 2015, to push ahead with research on the virus," she said.
"The current reduction in cases doesn't mean the virus isn't there. We still know very little about it.... We don't know if the virus can reactivate or mutate, like dengue fever, which now has four sub-types," she said.
"We need to better study this disease, which is here to stay."