Mayor Mitch Landrieu testified before Democrats in the U.S. House of Representatives on Thursday in support of President Barack Obama’s proposal to provide nearly $2 billion to fight the Zika virus.

In testimony to the House Democratic Steering and Policy Committee, Landrieu said officials should assume it is only a matter of time before the virus begins to spread in the United States.

“Local governments are the tip of the spear and will lead the Zika response on the ground,” Landrieu said. “We are thankful that, at this time, there are no locally transmitted cases of the Zika virus in New Orleans, and only four travel-related cases of Zika virus have been reported in Louisiana. Regardless, our mentality must be: ‘It is not a matter of if but when.’ ”

The Zika virus, which has been linked to severe birth defects in the children of pregnant women who have been infected, is a mosquito-borne illness that began setting off alarms last year as it spread in South America.

Estimates suggest at least 1.5 million people have been infected in Brazil and 3,500 children there have been born with microcephaly, a severe birth defect that leads to impaired brain function.

Louisiana is considered to be particularly at risk for locally transmitted cases of Zika because its mosquitoes are the same species as the ones that carry the virus and because of the large number of people who travel here from Central and South America.

Landrieu’s administration has developed a plan for combating Zika in the city, which would involve more intense mosquito-control efforts if the virus is detected.

“We’ve also doubled down on our year-round mosquito-control efforts, purchased new equipment and surveillance tools and launched an aggressive education campaign,” Landrieu said.

But he added that “to have a truly robust response appropriate to this serious public health threat, we need more federal resources.”

The Obama administration has sought about $1.9 billion to fight Zika, which would go toward funding research on a vaccine, but the request has stalled in Congress, where Republicans say the administration is not spending money already available to it.

As an interim step, the administration said last month it would redirect $589 million left over from efforts to quell the recent outbreak of Ebola.

But the administration argues that the Ebola money should continue to be used for its original purpose: funding prevention, detection and response efforts in 30 countries to try to prevent another outbreak of that disease.

Follow Jeff Adelson on Twitter, @jadelson.