Colombia says three people have died after contracting the Zika virus and developing a rare nerve disorder, according to BBC News.

Health Minister Alejandro Gaviria said there was a "causal connection" between Zika, the Guillain-Barre disorder and the three deaths.

Earlier, Brazilian scientists said they had detected for the first time active samples of Zika in urine and saliva. However, it is not clear whether the virus can be transmitted through bodily fluids.

Zika, a mosquito-borne disease, has been linked to cases of babies born in Brazil with microcephaly - underdeveloped brains.

Traces of Zika's genetic material were detected in saliva and urine during the 2013 outbreak in French Polynesia, but the Brazilian authorities say this is the first time "active" virus has been detected.

Brazil has seen 4,783 suspected cases of babies born with small brains, although only 404 of them have been confirmed, 709 have been rejected and 3,670 are still being investigated.

Meanwhile, the U.S. has advised men to abstain from sex or use condoms after visiting affected countries, if their partner is pregnant. The U.S. Centers for Disease Control believes a recent case of Zika was spread through sex.

The updated advice says avoiding mosquitoes remains the best way to prevent infection, but advises men returning from affected countries to "correctly use condoms during sex or abstain from sexual activity for the duration of the pregnancy".

Meanwhile, the governor of Puerto Rico has declared a public health emergency over Zika. The U.S. territory has 22 confirmed cases.