The Zika virus, which has already spread through South and Central America and the Caribbean, has now infected a number of Americans. It’s a serious disease that risks the long-term health of children. We’ve got to step up as a country and deal with this right now.

To date, there have been nearly 200 confirmed Zika infections in the continental United States. That includes 49 in Florida, 19 in Texas and 25 in New York, plus cases in Pennsylvania, Maryland, Hawaii and Indiana. So far, every one of those infections has been related to travel — people went to Central and South America, were bitten by infected mosquitos there, and came home with the virus. But we’re likely to see people become infected without leaving the United States — both because there is evidence that Zika can be sexually transmitted, and because mosquitos in this country will likely start spreading Zika as the weather gets warmer. This is already happening in Puerto Rico (whose residents, remember, are American citizens) where there are close to 160 cases today, and where experts predict that 1 in 5 people could become infected with Zika by summer. For an island without many public health resources, this is a serious problem.

Why does Zika matter? In great part because it’s been linked to microcephaly, a birth defect where babies are born with too-small heads, often leading to severe developmental delays. The heartbreak that microcephaly can cause families is devastating. And babies with microcephaly require a great deal of long-term medical care. That’s something that many families and communities just don’t have the resources to provide.

That’s why we’ve got to stop Zika before it spreads any further.

There is a lot we need to do, and fast. First and foremost, Congress should meet President Obama’s request for $1.8 billion in emergency appropriations to fight Zika. The president asked for this funding over a month ago, but on Saturday, Congress will begin a two-week break without having allocated one penny.

Instead, Congressional Republicans said the Administration should use funds left over from fighting Ebola — even though that money is still being used. Why would we lower our defenses against one public health threat in order to meet another one? That’s senseless and dangerous. Congress needs to provide the funds to fight Zika now.

Here’s where that money should go: developing a rapid diagnostic test for Zika; developing a vaccine; and developing treatment. We need to increase our research into the connection between Zika and microcephaly. And we need to step up mosquito control and abatement, and make sure the public knows how to protect themselves and their kids.

Some states have already stepped up to protect their citizens. Last month, Florida declared Zika a public health emergency in impacted counties. New York is offering free testing, and Governor Cuomo has just put forward a comprehensive plan to fight Zika throughout the state. I urge more states to follow suit, especially those with warmer climates.

Zika is real. It’s dangerous. It’s already reached the United States. We need to act now to protect people, especially pregnant women. There are smart, achievable things we could be doing right now, and there’s no time to waste. So we need Congress to act. We need citizens to demand action.

Together, we can keep families and children safe.