The Senate voted 68-30 to add anti-Zika measures to a 1.1 billion (982 million-euro) spending bill on Thursday, in defiance of the House of Representatives. The lower house of Congress had voted on Wednesday for a $622 million package, amounting to only a third of the funds sought by President Barack Obama, while demanding health cuts elsewhere to avoid deficit spending.

Obama had in February asked for $1.9 billion (1.7 billion euros) to fight Zika's spread via mosquitos and sexual contact. Severe defects in newborns have already dominated headlines in South America, especially Brazil.

The congressional votes set the stage for difficult negotiations between the Senate and House on a compromise bill amid surveys showing the American public worried about Zika.

Tom Frieden, who directs the US Centers for Disease Control and Prevention (CDC), told the Associated Press on Thursday that the House of Representatives' measure was "just not enough."

Lack of funding would hamper the CDC's ability to monitor women and babies with the virus over coming years, fight the mosquitoes that spread it, and develop better diagnostic tests, he said.

"This is an unprecedented situation," Frieden said. "We've never had a situation before where a single mosquito bite could result in you giving birth to a child with a terrible birth defect that could change the rest of your life."

To fight Zika, Obama's team has already allocated a leftover $600 million, mostly from the successful fight against Ebola. The White House called the House's plans for Zika woefully inadequate.

WHO plays down risk in Europe

On Wednesday, the World Health Organization (WHO) described the risk of a Zika outbreak in 18 European countries as only "low to moderate" as the northern hemisphere heads into summer.

Risks were higher in Black Sea coastal areas of Georgia and Russia and the Portuguese island of Madeira off Africa, the WHO added.

It cited the presence of the Aedes aegypti mosquito, which carry the Zika virus that can cause birth defects if contracted by a woman during pregnancy.

British health protection professor Paul Hunter said any outbreak in Europe would be "relatively short-lived."

Joint pain, fever

Zika can cause microcephaly, a form of brain damage, in unborn children. Currently, there is no vaccine or treatment. In most adults symtoms are mild in the form of a rash, joint pain or fever.

Since 2015, Brazil as the epicenter has recorded 1.5 cases of infection.

Last week, the WHO urged pregnant women not to travel to Rio for the Olympics.

ipj/msh (AFP, epd, AP, Reuters)