It's been three weeks since President Obama laid out his proposal asking for $1.9-billion to address the threat of the Zika virus.
So far, none has been approved.
On Wednesday, top health officials were back on Capitol Hill, trying to get those funds.
CDC director Tom Frieden says money is urgently needed to monitor and control mosquitoes, and to reduce the threat to pregnant women.
He says problems in Puerto Rico are escalating quickly.
Some in congress want the CDC to use money approved to fight Ebola in 2014.
But officials say there's little of that left, and pulling the remainder would jeopardize West Africa's response to another outbreak.
Health officials return to Congress for Zika funding
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