Nassau County officials announced a plan to prevent the spread of the Zika virus and other mosquito-borne diseases Wednesday, but they also downplayed the threat to Long Islanders.

Zika virus was declared an international public health emergency earlier this year. Pregnant woman are especially at risk because the virus can cause serious birth defects. Mosquitoes carrying the virus have been found in Mexico, Cape Verde, Africa, the Caribbean, Central and South America and the Pacific Islands.

Dr. Lawrence Eisenstein, Nassau's health commissioner, says Zika virus has not yet been transmitted by a mosquito in the United States.

Hundreds of people across the country have the virus, but federal health officials say they were infected while traveling abroad or through sexual contact with someone who was infected.

The CDC says the disease's primary carrier is a tropical mosquito not found in our area at this point. Some scientists, however, say the Asian tiger mosquito, which appears on Long Island in small numbers, may also carry the virus.

The Asian tiger mosquito is an invasive species that only recently arrived in the region, experts say. It's known to bite during daytime.

Suffolk County unveiled its plan two weeks ago, which included protection kits for pregnant women.

Both counties already trap, collect and test mosquitoes for a variety of viruses, including Zika.