Zika outbreak: safe sex guidelines extended by WHO

The World Health Organization said on Tuesday that men and women returning from areas where the Zika virus is actively spreading should practice safer sex or abstinence for 6 months, regardless of whether they are trying to conceive or showing symptoms.

The guidance is a change from the WHO's interim recommendation on June 7, which referred only to men and had a shorter timeframe of at least 8 weeks.

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The WHO said the update was based on new evidence on Zikatransmission from asymptomatic males to their female partnersand a symptomatic female to her male partner, as well asevidence that Zika is present in semen for longer than thought.

Zika infections in pregnant women have been shown to causemicrocephaly a severe birth defect in which the head and brainare undersized as well as other brain abnormalities. Theconnection between Zika and microcephaly first came to lightlast autumn in Brazil, which has since confirmed more than 1,800cases of microcephaly.

In adults, Zika infections have also been linked to a rareneurological syndrome known as Guillain-Barre, as well as otherneurological disorders.

Virus persists in semen

Sexual transmission of Zika had been reported in 11countries by Aug. 26, mainly through vaginal intercourse.

Therewas a first documented case of a man catching the virus throughanal sex in February 2016 and a suspicion of Zika transmissionthrough oral sex in April.

Although one man had Zika found in his semen 188 days afterthe onset of symptoms, the longest period that the virus has sofar been found to remain infectious was 24 days, and WHO saidits latest six-month advice was conservative.

In another Zika sufferer, the concentration of the virus inhis semen was 100,000 more than that in his blood 14 days afterhe was diagnosed.

Evidence on persistence of the virus in semen and itsinfectiousness and impact on sexual transmission remains limited
and the guidance will be updated again when there is moreinformation, WHO said.

WHO advises that pregnant women should not travel to areaswith ongoing Zika virus transmission, and it warned peopletravelling to the Paralympic Games, which starts on Wednesday inRio de Janeiro, to take precautions against mosquito bites.

"We think that the risk for travellers and athletes is low,but it's not zero," said WHO spokesman Tarik Jasarevic.

There is no vaccine or treatment for Zika, which is a close cousin of dengue and chikungunya and causes mild fever, rash and red eyes.