In a sign of mounting global concern over the Zika virus, health officials on Friday warned pregnant women to think twice about the lips they kiss and called on men to use condoms with pregnant partners if they have visited countries where the virus is present.

U.N. officials also called on many Catholic-majority countries in Latin America to loosen their abortion laws to allow women to terminate pregnancies if they fear the fetus may be at risk for a rare birth defect that causes brain damage and an abnormally small head, which may be linked to the virus.

The flurry of recommendations began in Brazil, where a top health official warned pregnant women to be cautious with their kisses.

Paulo Gadelha, president of the Fiocruz research institute, told a news conference that scientists have found live virus in saliva and urine samples, and the possibility it could be spread by the two body fluids requires further study.

He said that calls for pregnant women to take special precautions, and suggested they avoid kissing people other than a regular partner or sharing cutlery, glasses and plates with people who have symptoms of the virus.

“This is not a generalized public health measure, for the love of God,” he added, stressing both the seriousness of the discovery and reality that it was too soon to say how it could impact the epidemic.

Friday’s announcement coincided with the start of Carnival, a five-day bacchanalia that sees millions of people take part in alcohol-fueled parties where kissing as many people as possible is a top pastime. Gadelha underscored that the discovery needn’t alter Carnival plans for anyone but pregnant women.

He also stressed that the Aedes aegpyti mosquito, which spreads dengue, chikungunya and yellow fever as well as Zika, remains the virus’ main vector and said the fight against the mosquito should be a top priority.

The Fiocruz team studied samples from two patients who showed symptoms of Zika and tested positive for the illness. Tests on cell cultures showed the virus in the samples was capable of damaging the cells, meaning it was active.

Myrna Bonaldo, who headed the Fiocruz team behind the discovery, said she was particularly surprised the virus was found in urine because Zika is generally thought not to thrive in acidic mediums.

“Each discovery is a surprise and a new find for us,” she said. “For us scientists, it’s extremely challenging to understand Zika virus.”

Experts greeted Friday’s announcement with caution, saying the sample size was small and noting little is known about how the virus spreads.

Still, Dr. Elizabeth Talbot, a professor of infectious diseases at Dartmouth College, said it “does create further concern.”

“This virus is clearly throwing one curve ball after the other,” she said.

Asked about the guidance to pregnant women, Dr. Susan Donelan, medical director of the epidemiology department at Stony Brook University Hospital, said: “I can understand the Brazilian Health Ministry being concerned about not leaving out any potential mechanism for transmission, even if it’s theoretical.”

“Brazil is in a particularly difficult position” given the scope of the country’s microcephaly outbreak, she said.

Meanwhile, in Geneva, spokeswoman Cecile Pouilly said the U.N. High Commissioner for Human Rights was asking governments in Zika-affected countries in Latin America and the Caribbean to repeal any policies that restrict access to sexual and reproductive health services, including abortion.

“How can they … not offer (women) … the possibility to stop their pregnancies if they wish?” she said.

Pouilly gave the example of El Salvador, where about a quarter of women had experienced physical or sexual violence in the past year.

“So that also shows that many of these pregnancies are out of their control and countries obviously have to take that into account,” she said. Pouilly said that safe abortion services should be provided to the full extent of the law. “The key point is that women should have the choice and (make) informed decisions,” she said.

The National Conference of Bishops in Brazil, the South American country hardest hit by Zika, had no immediate comment on calls to loosen abortion laws. However, in a statement issued Thursday, the bishops said that the World Health Organization’s declaration earlier this week that Zika was an international emergency didn’t justify abortion.

Meanwhile, U.S. health officials said men who have visited an area with Zika should use condoms if they have sex with a pregnant woman — for the entire duration of the pregnancy.

The guidance issued Friday also says men might consider abstaining or using condoms even if they have sex with a woman who isn’t pregnant.

Zika virus disease is mainly spread by mosquitoes. But U.S. health officials detected a case of sexual transmission of the disease in Texas this week and in Brazil, officials said they had confirmed the virus was contracted via blood transfusions. For most people who catch the virus, it causes mild or no symptoms.

U.S. officials have recommended pregnant women postpone trips to more than two dozen countries with Zika outbreaks, mostly in Latin America and the Caribbean. Several Latin American nations have urged women to postpone pregnancies.

To date, the mosquito-borne virus has spread to more than 20 countries in the Americas.

One of those is Colombia, where health officials announced Friday that three people had died of Guillain-Barre syndrome after contracting the Zika virus. The country’s National Health Institute director, Martha Lucia Ospina, said all three victims were confirmed to have been infected with Zika, adding that their deaths show the virus can kill.

Still, most international experts are cautious about whether Zika can trigger Guillain-Barre, a rare syndrome that causes paralysis, because other infections and conditions can lead to the illness.