By Rick Ritter

SILVER SPRING, Md. (WJZ) — Warmer weather means more mosquitoes and the potential spread of Zika. The CDC is now revealing just how difficult it is to get a handle on the virus as Maryland takes steps to prevent mosquito breeding grounds.

Rick Ritter has more.

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Temperatures are heating up and so are concerns about Zika. The disease is spread primarily through the bite of an infected mosquito.

Here in Maryland, mosquito control spraying is already underway in Anne Arundel County and in other counties across the state.

The director of the CDC calls the mosquito that transmits the Zika virus “the cockroach of mosquitoes.” It’s highly resistant to insecticides—which makes it incredibly difficult to kill.

“To see them in a bottle which is coated with what should be a very effective insecticide happily flying around, minute after minute, hour after hour, shows us how important it is that we improve the methods we have in controlling mosquitoes,” said CDC Director Dr. Tom Frieden.

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The mosquito-borne virus has not been locally transmitted in the US but federal health officials continue to press Congress for funding to fight Zika, which can cause serious birth defects.

The CDC says the mosquito that transmits the virus tends to bite during the day and can bite four or five people at a time—making it capable of rapidly spreading disease.

That has the Maryland Department of Agriculture encouraging the public to help prevent the spread.

“Anything that holds water could potentially breed mosquitoes so those containers should be either dumped, drained or treated,” said Brian Prendergast, Maryland Department of Agriculture.

There are currently more than 500 travel-related cases here in the United States, including 17 here in Maryland.

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Vaccine testing is expected to begin in September but the CDC says it could take as long as two years to determine if one is safe and effective.

Rick Ritter