U.S. President Barack Obama has called for the rapid development of tests, vaccines and treatments for the Zika virus that has infected people in more than 20 countries in the Americas.
The White House said Obama convened a meeting of senior health advisers to discuss the spread of the mosquito-borne virus and the economic and developmental impacts on the region.
According to the World Health Organization, Zika virus could be linked to 4,000 suspected cases of microcephaly in Brazil, a condition that results in abnormally small heads in newborns and can affect brain development.
The U.S. Centers for Disease Control and Prevention has warned pregnant women against traveling to areas with Zika virus outbreaks.
U.S. health officials confirmed Tuesday that a man in Virginia had tested positive for the virus, but added there was no risk of it spreading to others because it is not mosquito season there.
On Wednesday, a hospital in Denmark said a tourist who had traveled to South and Central America has tested positive.
There is no treatment or cure for Zika virus infections, and the outbreak in the Americas has prompted public health warnings.
Authorities in El Salvador and Colombia have recommended women postpone getting pregnant.
In Brazil, 200,000 troops are traveling to homes to distribute pamphlets with advice on mosquito eradication, while crews are also fumigating areas that will be used for upcoming carnival celebrations and this year's Olympics.
The WHO's regional office in the Americas said Monday the most effective ways to stop the virus from spreading are to reduce mosquito breeding sites and for people to protect themselves from bites with insect repellent, nets, screens and clothing that covers as much of the body as possible.