Health

WHO calls Zika virus 'most likely explanation' for brain abnormalities

Zika virus infection in pregnancy is 'the most likely explanation' behind brain abnormalities in babies including microcephaly, the World Health Organization says.

More research to guide diagnosis, treatment and mosquito control recommended

Material to prevent Zika infection by mosquitoes are displayed at the World Health Assembly at the United Nations in Geneva, Switzerland. (Denis Balibouse/Reuters)

Zika virus infection in pregnancy is "the most likely explanation" behind congenital brain abnormalities in babies including microcephaly, the World Health Organization says. 

The United Nations health agency examined evidence from outbreaks of Zika virus infection to update its previous statement in March. 

The virus is also most likely a trigger of Guillain-Barré syndrome (GBS).

"Based on observational, cohort and case-control studies there is strong scientific consensus that Zika virus is a cause of GBS, microcephaly and other neurological disorders," the agency said in a statement on Wednesday. 

The agency's panel of experts also recommended more surveillance and research into diagnostics, vaccines, treatments and mosquito control.

The Zika virus is spread by mosquitoes and can also be sexually transmitted.

On Tuesday, WHO advised 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.

In February, WHO declared that the clusters of cases of microcephaly and neurological disorders occurring in areas with Zika virus transmission an international public health emergency. Last week, it  said the outbreak remains an international health emergency and the virus is continuing to infect new countries, such as in Southeast Asia.

Zika infections in pregnant women have been shown to cause microcephaly — a severe birth defect in which the head and brain are undersized — as well as other brain abnormalities.

The connection between Zika and microcephaly first came to light last fall in Brazil, which has since confirmed more than 1,800 cases of microcephaly.

There have been no reported cases of individuals infected by mosquitoes in Canada. 

Travellers are advised to protect themselves from mosquito bites at all times. 

The vast majority of people infected with Zika have a mild infection and about 80 per cent have no symptoms. The symptoms include mild fever, rash and red eyes.

With files from Reuters

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