The head of a top Brazilian health research institute said its scientists have discovered the presence of the active Zika virus in urine and saliva samples.

Travelers walk past a poster with information about the Zika virus during a campaign by Peru's Health Ministry at Plaza Norte bus station in Lima, Peru, on Feb. 4, 2016. Mariana Bazo | Reuters

Paulo Gadelha said at a press conference on Friday that the virus' ability to infect other people through the two body fluids requires further study. However, he noted that the discovery calls for special precaution to be taken with pregnant women. Brazilian researchers have pointed to a suspected link between pregnant women's infection with the virus and a rare birth defect in babies. The discovery does not yet merit any additional health recommendation, added Gadelha.

After confirming that the first case of the Zika virus was in a non-traveler in the continental United States, the Centers for Disease Control and Prevention issued new guidelines for pregnant women, and men with pregnant sex partners who have traveled to Zika-affected areas on Friday. One of the new recommendations mentions that men with a pregnant sex partner who reside in or have traveled to an area of active Zika virus transmission and their pregnant sex partners should consistently and correctly use condoms during sex or abstain from sexual activity for the duration of the pregnancy.

The CDC also provided updated guidance for health-care providers who are caring for pregnant women to include a recommendation that even those without the symptoms of the Zika infection should be tested after returning from areas affected by the outbreak. The suspected link between the Zika virus and a birth defect known as microcephaly appears "stronger and stronger" as researchers study whether there is a causal connection, CDC Director Tom Frieden said on Friday. "I wish we knew more about Zika today. I wish we could do more about Zika today," said Frieden. "I understand that this is a stressful situation for women and families."

In response to the reported discovery of the Zika virus in urine and saliva, Frieden said that the CDC would need more information in order to provide further guidance. "The bottom line is this is a mosquito-borne disease," Frieden told reporters. In the continental U.S., there have been about 50 cases of travelers who were diagnosed with the Zika virus, including three pregnant women. Since there is no vaccine or specific drug to treat Zika, stopping travel to locations that have Aedes mosquitoes is the primary form of preventing the virus from spreading to the United States.

To stop the further spread of the virus, the CDC has issued a travel alert to 30 countries and territories, which include popular vacation destinations such as Puerto Rico, Mexico and Barbados.