What do I need to know about Zika?

The mosquito-borne Zika virus was declared a Public Health Emergency this year. We give you the low-down on the outbreak.

By Alexander Kumar
Published 25 Sept 2016, 16:00 BST, Updated 7 Jul 2021, 16:20 BST
Street scene

Street scene.

Photograph by Getty Images

Is Zika just in South America?
The virus was named after Zika Forest in Uganda, where it was first identified in 1947. In February 2016, the World Health Organization (WHO) declared Zika virus a Public Health Emergency of International Concern. Worldwide outbreaks are currently affecting many tropical areas and, with no effective method of controlling it, the mosquito-borne virus will continue to spread across the globe, alongside increasing imported cases among travellers returning home from affected countries.

Will I know if I have it?
Not necessarily. Zika tests are notoriously unreliable, and most people won't have symptoms — but these 'silent carriers' can still transmit it. It can spread through infected men, as it stays in semen longer than in other body fluids. Men should use condoms or abstain from sex. Symptoms are mild, involving fever, rash, joint pain or red eyes. Patients typically don't get sick enough to go to hospital.

Can I catch it from water?
There are no cases of water-borne transmission, but bodies of standing water are considered high risk for exposure between dawn and dusk as Zika can be spread through bites from infected mosquitoes in such areas.

Can I prevent an infection?
Absolutely. Sleep under an insecticide-treated bed net, wear long sleeves and apply repellant regularly. Air-conditioned accommodation, window screens and door screens all deter mosquitoes. Some governments are advising pregnant women to avoid travelling to high-risk areas, and recommending those who live in high-risk regions to delay pregnancy.

What are the effects?
It can cause Guillain-Barré syndrome, which affects the nervous system. When passed from mother to foetus, Zika can cause microcephaly, a condition in which a baby's head is abnormally small and the brain does not fully develop.

Alexander Kumar is an academic doctor specialising in infectious diseases and tropical medicine

Published in the South America 2016 guide, distributed with the October 2016 issue of National Geographic Traveller (UK)

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