Authorities in Brazil yesterday said that Zika had been detected in patients' saliva and urine, adding to the concern over the spread of the virus, even as officials offered new guidance on sex for people returning from Zika-hit regions.
Zika, linked to thousands of birth defects in Brazil, was believed to be primarily transmitted through mosquito bites, however, word had surfaced last week of sex and blood transfusions passing on the infection.
Also the presence of the virus in the saliva and urine of two patients had caused new worries.
According to commentators, the possibility of the infection being spread through body fluids could complicate efforts to contain the outbreak.
In fact, pregnant women have been urged by the Brazilian federal biomedical research institution to not kiss strangers during the Carnival of Brazil celebrations.
Meanwhile, the US Centers for Disease Control and Prevention recommended more stringent measures for monitoring pregnant women for Zika and for the prevention of sexual transmission of the virus.
"I wish we knew more about Zika today," CDC director Tom Frieden told reporters.
According to the CDC, men with a pregnant partner who lived in or had travelled to an area of active Zika transmission needed to use condoms during sex with their partner or abstain from sex for the duration of the pregnancy.
"The science is not clear on how long the risk should be avoided," the CDC said.
The Americas had witnessed rapid spread of Zika, which led the World Health Organization to declare an international public health emergency due to its link to microcephaly, a condition in which infants are born with abnormally small heads and could suffer developmental problems.