Federal scientists have calculated a 20-fold increase in specific birth defects occurring nationwide since the abrupt emergence of the Zika virus — abnormalities that once were hardly known but now are capturing headlines.

Microcephaly — small head and brain size — as well as other brain malformations, eye defects, and central nervous system disturbances, were estimated to affect 3 of every 1,000 births in the pre-Zika era — 2013-2014 — in the United States.

But in 2016, women infected with the Zika virus gave birth to babies with pathogen-related abnormalities, leading to a noteworthy spike in the proportion of infants born with the same defects. Epidemiologists at the Centers for Disease Control and Prevention reported Thursday that nearly 60 in every 1,000 pregnancies involved a Zika-related abnormality.

Among those birth defects, microcephaly was diagnosed 33 percent more often in the United States since the virus was first detected here a year ago.

“All of these cases were travel-related, which means these women acquired the virus outside of this country,” said Dr. Aaron Glatt, who chairs the Department of Medicine at South Nassau Communities Hospital in Oceanside. “We have been emphasizing that women who traveled to endemic areas to get tested.”

The CDC is cautioning women not to travel to global regions where Zika infections are common.

At least six babies were known to have been born in New York last year, according the state Deparment of Health.

advertisement | advertise on newsday

CDC officials report on their website that 1,534 women in the continental U.S. were known to be infected with the virus while pregnant. These are women who had laboratory-confirmed infections in 2016 through Feb. 21, 2017. An additional 3,225 pregnant women during the same period in the U.S. terrirories also had laboratory confirmed infections.

Scientists are still studying why some infected women give birth to babies with devastating abnormalities and others do not. In January, researchers at Baylor University in Texas found that specific placental cells can harbor the virus providing a conduit to the developing fetus.

In reponse to the CDC’s new research, the March of Dimes, headquartered in White Plains, announced Thursday that special health care and social services are urgently needed for babies born with Zika-related abnormalities.

“This study makes clear the grave consequences of Zika infection for pregnant women and their babies,” Dr. Paul Jarris, chief medical officer said in a statement Thursday.

Glatt, meanwhile, a specialist in infectious diseases said there are two answers to the threat posed by Zika and other mosquito-borne infections.

@Newsday

“I think the answer to all of these problems is mosquito control and a vaccine,” said Glatt, a spokesman Infectious Diseases Society of America. “There is a tremendous amount of work underway on the vaccine.”