Scientists in Brazil advise pregnant women against kissing anyone showing symptoms but others believe virus may behave more like dengue fever

The discovery of the Zika virus in saliva has sparked disagreement among Brazilian scientists about whether pregnant women should be advised to avoid kissing anyone showing possible symptoms.

The Fiocruz research institute in Rio de Janeiro said on Friday they had identified live samples of Zika in saliva and urine, which merited further research into whether these two fluids could be a source of contagion.

Until the outcome is known, they suggested pregnant women should think twice about kissing anyone other than their partners or sharing drinking glasses or cutlery with people who might be infected.

This proposed precaution has been met with a mixture of fear and derision. Other scientists argue that it is extremely unlikely for the disease to spread this way.

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“The warning is crazy and unnecessary,” said Rubio Soares Campos, who co-identified the first case of Zika in Brazil. “Just because the virus is present in saliva does not mean it can be transmitted that way.”

He argued that it was more likely to behave like dengue, another mosquito-borne disease that is found in human body fluids but cannot be spread that way.

But the latest news has increased the unease of the Brazilian public, who have watched with alarm as Zika has come from nowhere to infect an estimated 1.5m people with an apparently growing range of suspected – but not yet scientifically proven – side effects, including immune system disorders and brain defects in newborns.

“It’s starting to scare the hell out of me,” said one Rio resident, Maria Teixeira. “At first everybody thought is was just a mild fever. Then, we were told it could develop into Guillain Barré syndrome, and then that it was associated with horrible side effects such as deformed babies. What’s next?”