WASHINGTON (Reuters) - Facing pressure from Republicans and some in his own Democratic Party to act strongly on Zika, President Barack Obama will ask the U.S. Congress for more than $1.8 billion in emergency funding to fight the mosquito-borne virus.
Most of the money would be spent in the United States on testing, surveillance and response in affected areas, and on research into a vaccine, with some funds also going to help countries grappling with the virus, the White House said on Monday.
The World Health Organization has declared an international health emergency over Zika. While the disease is normally mild, scientists suspect that when pregnant women are infected the virus can cause microcephaly, a birth defect marked by an abnormally small head. Zika has been reported in 33 countries.
In the continental United States, there have been 50 confirmed cases of Zika in people who have traveled to affected areas. The virus is already being actively transmitted in Puerto Rico and other U.S. territories in warmer areas with populations of the Aedes aegypti mosquito. Officials say the country needs to be ready to stop the spread of Zika when winter ends in the United States and mosquito populations become active.
Obama urged Americans to remain calm. "The good news is this is not like Ebola, people don't die of Zika. A lot of people get it and don't even know that they have it," Obama told CBS News in an interview that aired on Monday.
See photos from the unfolding health emergency:
"But there shouldn't be panic on this, this is not something where people are going to die from it. It is something we have to take seriously," he said.
The White House was criticized during the 2014 midterm elections for a slow reaction to domestic fears about Ebola, a virus that killed more than 11,300 people, mostly in three West African countries, in a two-year epidemic. Many Republicans called then for travel bans from the affected areas.
Zika was an issue in a debate on Saturday between Republican candidates for the Nov. 8 U.S. presidential election, with two contenders saying they would quarantine travelers if needed to stop the spread of the virus.
%shareLinks-quote="The good news is this is not like Ebola, people don't die of Zika. A lot of people get it and don't even know that they have it" type="quote" author="President Obama" authordesc="" isquoteoftheday="false"%
The WHO has not recommended any travel or trade restrictions related to Zika, although it notes that some governments may make travel recommendations to their own populations.
Last week, Senate Democrats urged Obama to take "an urgent and aggressive response" to Zika.
Top U.S. health officials are set to brief Congress on the virus and the funding request this week.
Dr. Anthony Fauci of the National Institutes of Health and the CDC's Dr. Anne Schuchat were due to talk to reporters at the White House about the request later on Monday.
Obama is seeking $250 million to help Puerto Rico provide health services to pregnant women and affected children. Officials have confirmed 22 cases of Zika in the financially struggling territory.
More on AOL.com:
More than 3,100 pregnant women in Colombia have Zika virus: government
To avoid Zika virus, CDC says pregnant women should use condoms or abstain from sex
Scientists find Zika in saliva, urine; unclear if can transmit infection