The Health Department says four more babies have been born with the Zika virus in New York.

Side effects of the disease include smaller heads and brain or eye problems.

That brings the total to five babies who have been born with the virus so far in the city, and eight other infants have tested positive without showing any symptoms. Those eight will be monitored for at least a year.

Health officials are urging pregnant women or women who might be pregnant to avoid areas where Zika may be transmitted.

According to the Department on Health, as of Dec. 2, 8,000 New Yorkers have been tested for Zika virus. Of those, 962 have tested positive, including 325 pregnant women. All of the cases were associated with travel.

The virus itself primarily spreads through mosquito bites. Six of the positive tests in NYC were transmitted sexually.

"Remember to practice safe sex, because the risk is still there," says Oxiris Barbot, the Health Department's first deputy commissioner. "What we're finding is that with some of these infants, the moms don't remember being symptomatic during their pregnancy."

The city is also launching an ad campaign discouraging travel to places like the Caribbean, Mexico, Central and South America and parts of Miami.