Officials say 49 pregnant women have tested positive since New York City started its Zika action plan in April.
One baby has been born with microcephaly due to the virus.
Overall, more than 3,400 at-risk pregnant women have been tested under the program.
Mayor de Blasio said Tuesday that the city has committed $21 million to protect New Yorkers from Zika.
He and other politicians, including U.S. Rep. Carolyn Maloney, called on Congress to approve $1.9 billion in emergency funding.
Copyright AP - Associated Press
