WASHINGTON (Reuters) - The White House said on Friday that it would be “profoundly unwise” to plow money set aside for Ebola-related projects into research and mitigation efforts for the mosquito-borne Zika virus as several top Republican lawmakers have requested. Democratic President Barack Obama has asked the U.S. Congress for more than $1.8 billion to fight Zika in the United States and abroad, and pursue a vaccine. But three key Republican lawmakers in the House of Representatives have said they think the government should instead draw from $2.7 billion that has not yet used for public health projects overseas. The Zika virus has been linked to birth defects in Brazil and spread to at least 31 other countries and territories, mostly in the Americas. Representative Hal Rogers, chairman of the House Appropriations Committee, and Representatives Kay Granger and Tom Cole, who are appropriators for Health and Human Services and the State Department, made their request in a letter to the White House on Thursday. “If the aim of the request is to mount as rapid a response as possible, it is clear to us that the most expeditious way to identify the needed funding is to maximize the use of unobligated funds previously provided for Ebola,” the lawmakers said. Senator Roy Blunt of Missouri, a member of the Republican Senate leadership team, said earlier this month that Obama should repurpose Ebola funds for the new Zika fight. But White House spokesman Josh Earnest said the unspent Ebola money was needed to “build up the public health infrastructure of countries overseas” to help prevent future epidemics. West Africa was stricken by a two-year Ebola epidemic that killed more than 11,300 people starting in December 2013 and led to cases in the United States.  “It’s critically important that we follow through on those efforts and it would be profoundly unwise to take money away from the ongoing effort that’s need to fight Ebola,” Earnest said. Earnest said that the White House would soon put forward a formal Zika funding request for lawmakers. It will include a plan to redirect some Ebola funds to the Zika fight, but Earnest said new funding was also require. Much remains unknown about Zika, including whether the virus actually causes microcephaly, a condition marked by unusually small heads that can result in developmental problems. Brazil said it has confirmed more than 500 cases of microcephaly, and considers most of them to be related to Zika infections in the mothers. Brazil is investigating more than 3,900 additional suspected cases of microcephaly. 