WASHINGTON, D.C. — "We have a narrow window of opportunity to scale up effective Zika prevention measures," Centers for Disease Control and Prevention Director Tom Frieden said Thursday. "And that window of opportunity is closing."

Wednesday, the CDC revealed that up to 13 percent of pregnant women infected with Zika in their first trimester will have babies with microcephaly, a potentially life-threatening birth defect which causes a baby's head to be smaller than normal. There were 591 people in the continental United States infected with the mosquito-borne Zika virus at last count. U.S. mosquito season officially begins Monday.

So how does Congress respond to this delicate moment in the fight against a terrifying disease? Not by passing a robust funding bill to combat Zika, as the White House requested. The House passed a funding bill at about half the level of a companion bill in the Senate and one-third the White House's proposed figure. President Obama has threatened a veto.

And the House passed another bill that critics say guts clean water laws in the name of Zika, without actually doing anything to fight the outbreak. Democrats Thursday called on the Republican leadership to cancel the Memorial Day recess and get back to work until they're able to reach a resolution on Zika funding and a few other urgent pending matters.

Despite these demands, the House adjourned before 1 p.m. Thursday, with lawmakers running for the exits to catch planes home for Memorial Day parades and fundraising visits.

Will pesticides in the water help combat Zika?

The Zika Vector Control Act, which passed the House Tuesday 258 to 156, aims to reduce transmission of the virus by eliminating some environmental regulations on the use of pesticides in waterways, where mosquitos can breed. Opponents say it's actually just an end-run against EPA pesticide regulations that the GOP has been trying to push through since 2011. Rep. Peter DeFazio (D-OR) says it's the fifth time House Republicans have trotted out this bill as a response to the crisis of the day. "When we were having West Nile, they called it a West Nile bill," DeFazio said on the House floor. "Then, when we were having a bad fire season, they called it a Fire Suppression Act."