ATLANTA — The government urged health officials around the country Friday to get ready now in case there are outbreaks of the mosquito-borne Zika virus in the U.S. this summer.

A Zika epidemic has been sweeping through Latin America and the Caribbean, and officials say it’s likely some small clusters of Zika will occur in the U.S. when mosquito numbers boom.

At a “Zika Summit” on Friday, experts prodded some 300 state and local officials gathered at the Centers for Disease Control and Prevention headquarters to make Zika response plans now.

When West Nile virus – transmitted by a different mosquito – moved through the U.S. about 15 years ago, health officials were caught flat-footed, noted Dr. Georges Benjamin, executive director of the American Public Health Association.

“This is an opportunity to get ahead of the curve,” he told the summit’s attendees.

The Zika virus causes only a mild and brief illness, at worst, in most people. But in the last year, infections in pregnant women have been strongly linked to fetal deaths and to potentially devastating birth defects, mostly in Brazil.

The virus is spread mainly by Aedes aegypti mosquitoes, which also live in parts of the U.S. It was thought to be mainly in the South but the CDC revised its map this week, showing the mosquito has been found in parts of the Midwest and Northeast.

Officials don’t expect Zika to be a big problem, though, in the U.S. for a number of reasons, including the widespread use of air conditioning and screens. The Zika mosquito likes to bite indoors. Officials say the clusters may be small and surface only in a few states – most likely Florida and Texas. But they don’t know for sure.

So far, there have been no Zika infections in the U.S. caught from mosquitoes. More than 300 illnesses have been reported, all linked to travel to Zika outbreak regions.

About 350 additional cases have been reported in U.S. territories, most of them in Puerto Rico, where mosquitoes are already spreading the virus. Together, dozens or even hundreds of births in the 50 states and territories could be affected in devastating ways by Zika, said Dr. Edward McCabe of the March of Dimes, who spoke at the summit.

“We have a few short weeks to stop the Zika virus from gaining a foothold,” McCabe said.

During the summit, state and local officials were encouraged to map where the Zika mosquito lives and breeds in the state and which insecticides would work best in their area.

Workers likely will go door-to-door, sometimes asking to go on properties and spray.