The administration said Tuesday that, as of May 11, there were 1,200 Zika cases on the mainland and in U.S. territories, among them more than 110 pregnant women with confirmed cases of the virus. (Felipe Dana/AP)

There is government speed, and then there is virus speed. They’ve been mismatched in this year of Zika. The political apparatus of Washington has been sluggish compared with the epidemic that already has taken hold in Puerto Rico and poses a serious threat to the mainland United States as mosquito season arrives.

On the Hill, the Republican-controlled House and Senate have different ideas about how much emergency money should be appropriated to combat the contagion — as well as where that money should come from and whether it has to be offset by spending cuts elsewhere.

President Obama asked for $1.9 billion in February. The House, with a rowdy caucus of hard-line conservatives, has asked the Obama administration to redirect $622 million in unused Ebola epidemic funds to fight Zika. The Senate, meanwhile, voted Tuesday to move forward on a bipartisan compromise that would provide $1.1 billion in emergency Zika funds.

Settling these differences may not happen soon, even as concerns about the virus grow.

Although Republicans in both chambers are worried about the coming public health crisis and say they want to move the funding quickly, House GOP leaders are sticking with their long-held stance that the cost of emergency funding for health and weather disasters should be offset. They are being pressured by influential conservative groups, such as Heritage Action, to maintain this stance, especially after Senate leaders struck a deal with Democrats after determining that it isn’t worth being blamed for delaying Zika funds over a budget fight.

On Tuesday, Obama threatened to veto legislation if it tracks the parsimonious House legislation.

There are many political and epidemiological repercussions here. A potential danger for Republicans is that they will face a backlash, particularly among female voters, for being slow to provide money for a disease that can cause birth defects. But many face primary battles in which they will want to show that they won’t bend on spending.

The virus continues to spread. The administration said Tuesday that, as of May 11, there were 1,200 Zika cases on the mainland and in U.S. territories, among them more than 110 pregnant women with confirmed cases of the virus.

The scientists on the front lines are anxious and impatient, and two top U.S. officials have questioned whether the cumbersome appropriations process is agile enough to fight mindless microbes guided only by a genetic command to replicate.

“When you’ve got an emergency situation, you really need to get funding as quickly as you possibly can,” said Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases. “We’re running out of time.”

He said his institute has several candidates for a Zika vaccine and could have preliminary trials as soon as September. Meanwhile, researchers want to study the mechanisms of infection and find ways to stop transmission.

The virus has been conclusively linked to births of babies in South America with unusually small heads — microcephaly — and it has been implicated in other neurological diseases. The virus can be spread through sexual contact. So far, the cases in the mainland U.S. have involved travelers who were infected elsewhere and returned to the country.

Fauci endorsed an idea that has also been embraced by Tom Frieden, director of the U.S. Centers for Disease Control and Prevention: The government could establish a permanent, replenishable emergency fund to combat epidemics. Frieden told reporters last week that Congress can’t move at the speed of an epidemic and that the government needs to have resources ready to deploy in a crisis.

Frieden echoed that in an email Tuesday asking for comment on the political battle on the Hill:

“The political process is meant to be deliberative. However, emergencies require immediate action. With disease outbreaks, if we have the resources to respond immediately, we can change the course of an epidemic, saving dollars and – more importantly – lives. We know there will be another public health emergency. We don’t know when, where it will come from or what it will be, but we are 100% sure it will happen,” Frieden wrote.

The Ebola epidemic that erupted in West Africa in 2014, and reached the United States and Europe, exemplified the mismatch between government decision-making and emerging pathogens.

Not until Ebola was completely out of control did the World Health Organization declare a global emergency.

More than a month later, Obama ordered the U.S. military to build temporary hospitals in West Africa. But by the time the soldiers deployed and construction began, the epidemic had largely subsided — not so much because of the government response, but because local leaders persuaded citizens to change burial practices and other behaviors that could spread the disease.

Since the epidemic was declared officially over in January, there have been small flare-ups of the disease due to the virus’s persistence in some survivors. The CDC has 100 staff employees doing surveillance in West Africa and testing blood samples, White House press secretary Josh Earnest said Tuesday.

He said the House measure to fight Zika is “woefully inadequate.”

“The House of Representatives is three months late and more than a billion short of doing what’s necessary to protect the American people,” Earnest said.

But House Appropriations Committee Chairman Hal Rogers (R-Ky.) said this week that the administration hadn’t been forthcoming with information about how the money would be spent. He said his plan would release money immediately.

“Given the severity of the Zika crisis and the global health threat, we cannot afford to wait on the Administration any longer,” Rogers said in a statement.

But on the other side of the Capitol, some senators have lost patience with the House.

After years of partisan rancor, Republicans and Democrats in the Senate have worked in recent days to try to approve several bipartisan spending bills. Senate Majority Leader Mitch McConnell (R-Ky.) announced last week that Zika funding would be considered as an amendment to a widely supported package of bills providing spending for veterans, transportation, housing and military constructions agencies.

“The House needs to wake up to the fact that this is an emergency,” said Patty Murray (D-Wash.), who co-wrote the Zika amendment that moved forward in a procedural vote Tuesday. “People’s health and lives are at risk, and they need to step up to the plate.”

Sen. Roy Blunt (R-Mo.), who co-sponsored the amendment with Murray, told reporters that the proposal would allow the government to battle Zika until September 2017, when a vaccine will probably be available for widespread use.

“Once a vaccine is available, this is a very different environment to deal with,” Blunt said.

Geography matters here, too. Sen. Marco Rubio (R-Fla.) is among senators in the South nervous about Zika, and he favored the full $1.9 billion requested by Obama.

Sen. Lindsey O. Graham (R-S.C.) said Tuesday he would normally prefer to offset the cost of any new spending with corresponding cuts but that his home state of South Carolina is in the crosshairs of a potential Zika disaster.

“I wish we could pay for it,” he said. “I just don’t see that happening in a bipartisan fashion in both houses.”

Lenny Bernstein contributed to this report.