Infectious Diseases

Updated 02 June 2016

Zika infections through sex more common than thought

Waiting at least eight weeks before trying to conceive is now recommended for people in Zika-prone areas.


Women planning to become pregnant should wait at least eight weeks before trying to conceive if they or their partner live in – or are returning from – areas where Zika virus infections are occurring, UN health officials now recommend.

Mild symptoms

Mosquito bites remain the most common source of infection of the virus that causes the severe birth defect microcephaly, which results in babies with abnormally small heads and brains. But transmission of the virus through sex is more common than previously thought, according to World Health Organisation officials. They had previously recommended a four-week abstinence before trying to conceive.

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And if the male partner has had symptoms of Zika infection, couples should wait six months before trying to have a baby, the WHO officials said.

Four out of five people infected with Zika don't develop any symptoms. Those who do most often suffer from mild symptoms that include fever, rash, joint pain or red eyes.

The true risk of Zika is to a developing fetus.

Brazil is Zika hot zone

The vast majority of Zika infections have occurred in Latin America, with Brazil the hot zone with an estimated 5 000 cases of microcephaly. There have been no reports of Zika-induced microcephaly contracted in the United States. But US health officials have said they expect to see Zika infections in Gulf Coast states such as Florida, Louisiana and Texas as mosquito season picks up.

Earlier this month, US health officials reported that the number of pregnant women in the United States infected with the Zika virus had tripled because cases were now being counted in a more comprehensive way.

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So far, an estimated 280 infected women are being followed in the United States and its territories, according to two registries that have been created by the US Centers for Disease Control and Prevention.

Three-pronged strategy

Previously, only cases of pregnant women who had Zika-related symptoms or pregnancy complications were being tallied, CDC officials said. But recently published reports have found that some pregnant women show no symptoms of Zika infection, yet still give birth to babies with microcephaly.

To limit any potential spread of Zika virus via mosquitoes, health officials on the federal, state and local level are deploying a three-pronged strategy: improving mosquito control; expanding their ability to test for Zika; and urging the public to protect themselves against mosquitoes.

Women of child-bearing age who live in an active Zika region should protect themselves from mosquito bites by wearing long-sleeved shirts and long pants, using mosquito repellent when outside, and staying indoors as much as possible, according to the CDC.

President Barack Obama has asked Congress to allocate $1.9 billion to combat the Zika threat, but lawmakers have yet to agree on a spending package.

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