Ministers from 14 countries including the two reportedly worst affected, Brazil and Colombia, gathered in Uruguay to coordinate their fight against the mosquito-borne illness which authorities fear may spread worldwide.
Arriving at the meeting in Montevideo, Brazil's Health Minister Marcelo Castro told reporters his country had deployed 522,000 personnel to prevent infections by cleaning up and advising the population.
He called it "the biggest effort in Brazil's history."
The fever starts with a mosquito bite and normally involves little more than a fever and rash.
Also Read
But scientists suspect that when it strikes a pregnant woman, it can cause her fetus to develop microcephaly -- a condition which causes the baby to be born with an abnormally small head.
Since October, Brazil has reported 404 confirmed cases of microcephaly -- up from 147 in 2014 -- plus 3,670 suspected cases.
Doctors have also linked Zika to a potentially crippling neurological disorder, Guillain-Barre syndrome.
Alarm bells rang on Tuesday when authorities in Texas said they had confirmation of the virus being transmitted by sexual contact and not just tropical mosquitoes.
The World Health Organization has declared the spike in serious birth defects in South America an international emergency and launched a global Zika response unit.
Officials in India worry it could be next, noting that the Zika and dengue fever-carrying Aedes aegypti mosquito thrives in its teeming cities.
Cape Verde off northwest Africa has also detected a case of Zika.
The WHO today warned European countries to act early to prevent the spread of Zika.