Are YOU at risk of the virus that can shrink babies’ brains?

As global emergency is declared over infection spread by mosquitoes

An INCURABLE virus that s hri nks babies’ brains sounds like the stuff of nightmares. And there i s no denying the headlines about the zika virus have made alarming reading over the past week, with one expert from the World Health Organisation (WHO) describing its spread as ‘explosive’ — yesterday the organisation declared the virus a global health emergency.

zika, which was identified in Africa in the Forties, was first reported in Brazil just eight months ago, but it has already now spread to 23 other countries in the region, including Mexico and Barbados, with predictions that the numbers affected could rise to four million by the end of the year.

Meanwhile, 31 Americans, four Canadians and three Britons have tested positive for zika — all were infected while travelling.

However, a study published in The Lancet suggests around a third of the 9.9 million foreign tourists who visited risk areas in Brazil in a year, returned to Europe.

Here we look at why zika has suddenly become a major health concern and what you need to know to protect yourself.

WHY IS THE ZIKA VIRUS SUCH A WORRY?

THE zika virus is transmitted through infected blood carried from person to person by the bite of the female Aedes aegypti mosquito, which originated in Africa, but is now found in tropical and subtropical regions.

The greatest concern is that zika may be linked to babies being born with microcephaly — unusually small heads and brain damage — although the link has not been proven beyond doubt.

It is likely that the highest risk is in the first trimester, although there is some evidence the birth defect can occur later on in the pregnancy, too.

The rate of children being born with microcephaly in Brazil has gone up 20-fold since the first case of the infection was reported, with 4,000 cases since last October.

‘Studies are ongoing to prove the link once and for all but it does look very likely that zika is to blame,’ says James Whitworth, a professor of international public health at the London School of Hygiene & Tropical Medicine. One theory is that the virus has undergone a subtle mutation which means that it damages babies by crossing the placenta, when it didn’t before.

However, Professor John Oxford, a virologist at Queen Mary, University of London, believes this is unlikely.

‘Other viruses in this family of viruses known as flaviviruses (which include dengue and tickborne encephalitis) have not mutated in the past 50 years, so it seems unlikely that zika would change suddenly.’

Some experts believe the link between zika and microcephaly was always there, but was missed simply because it was affecting populations that had poor healthcare reporting, or higher levels of ‘background’ birth deformities.

‘The sheer numbers of people involved in this latest outbreak is what has made it really obvious,’ says Professor Whitworth.

WHAT’S THE RISK IF I’M NOT PREGNANT?

WHILE pregnant women are the main focus of concern, people who catch the virus may also be at risk of a rare nervous system disorder, Guillain-Barre syndrome, that can cause temporary paralysis and, in rare cases, death. A health minister in Colombia has said there’s been ‘a substantial increase in the number of people reported with Guillain-Barre’ in the past week, from the usual 15 to hundreds.

COULD THERE BE A UK OUTBREAK?

THERE is no risk of zika becoming a public health emergency here, insists Professor Whitworth.

‘The major way of transmission is through the bite of a type of mosquito which thrives in warm tropical zones.’

Professor Oxford adds: ‘ In the past, it tended to appear on the plains of Africa. now that it has spread to Brazil, i t has exploited densely populated urban areas where many people collect rain water to drink and store it near mosquitoes.

‘This makes it easy for the mosquitoes, which bite any time during the day, to breed right next to people and pass infected blood quickly from person to person.’

It is possible that mosquitoes could travel to the UK on board container ships, and there has been a claim that they have been found on the Kent coast, but experts insist that they would not live long in our climate.

More than 30 species of mosquitoes do breed in the UK, including Anopheles plumbeus which can carry malaria but not zika virus.

CAN I GET IT FROM A VISITOR TO BRAZIL?

EVEN people who’ve caught zika in South America and returned to the UK would not be able to easily pass it on — it is ‘very unlikely’ that the virus can be passed on by normal contact between people, says Professor Oxford. ‘It’s not catching unless you share blood, or needles.’

There are concerns the virus could be passed on from infected men to women during intercourse, and couples should delay trying for a baby for a month if a man has returned from a country affected by zika virus. But Public Health England advises: ‘Sexual transmission of zika virus has been recorded in a limited number of cases, and the risk of sexual transmission of zika virus is thought to be very low.’

However, if a female is already pregnant, condom use is advised for 28 days after a man has returned from a zika transmission area as long as he has no symptoms.

The guidance changes if a man returns with obvious symptoms including a fever and rash, and men are advised to use condoms for six months following recovery.

HOW WOULD I KNOW IF I HAD ZIKA?

MANY people — up to 80 per cent — who are infected have no symptoms at all, according to the European Centre for Disease Prevention and Control, so they may never even know they have contracted the infection.

When someone does have symptoms, these appear a few days after they’ve been bitten by an infected mosquito and are usually mild — a fever and a rash which soon goes away. Some people also suffer from muscle and joint pain, or get conjunctivitis. The symptoms usually clear in two to seven days. There is no specific treatment for zika, but people who have the telltale symptoms should drink fluids to prevent dehydration and take paracetamol, says NHS Choices.

CAN I BE GIVEN A VACCINE?

THERE is no vaccine or medication to prevent infection, although there have been reports that a vaccine could be available next year. Efforts to make one have just begun, and creating and testing a vaccine normally takes years. However, Glaxo Smith Kline has announced that it is fast-tracking studies to see if it can use existing vaccine technology to work on a zika vaccine.

Canadian scientist Gary Kobinger, who worked on the Ebola vaccine and is part of a consortium working on a zika vaccine, has revealed that the first stage of human testing could start in early August — meaning it could be ready by autumn.

SHOULD I AVOID SOUTH AMERICA?

IT’S not just the parents of gapyear students who might be worried about the news, as hundreds of thousands of spectators are expected to congregate in Rio for the summer Olympic Olympics. Based on available evidence, theth WHO has not issued any travel or trade restrictions rela relating to the zika virus.

Dr Ben neuman, av virologist at the University of Read Reading, says he would go to the Olympics himself, pointing out that there would be fewer mosquitoes in the summer which is the dry season and symptoms for everyone except pregnant women tend to be mild.

CAN’T I JUST USE REPELLENT?

INSECT repellent can help keep mosquitoes at bay, but not all products are effective and many need to be reapplied regularly.

A 2002 study in the new England Journal of Medicine found that Deet-based repellents provided the best and longest-lasting protection against mosquitoes, while some botanical-based bug sprays lasted less than 20 minutes.

‘Mosquito repellent containing Deet is effective, but it can cause skin redness and irritation,’ says Professor Oxford.

The Brazilian government is set to deploy 220,000 soldiers to try to eradicate the mosquitoes before the Olympics.

But wiping them out could prove almost impossible. ‘Spraying with insecticide could work around the Olympic stadium, but it’s not going to have much effect if you try to spray the entire Amazon Basin,’ says Professor Whitworth.

WHAT IF I AM PREGNANT?

PREGNANT women have been advised not to travel to any of the 23 infected countries, and many airlines are offering pregnant women the chance to change flights that have been booked to affected areas. Professor Oxford strongly advises pregnant women not to go to the Olympics.

‘Don’t take the risk. you can wear as much mosquito repellent as you like, but it still takes only one bite to get infected.

‘ We don’t know how many pregnant women who get this virus go on to have babies with birth defects, but it could be very high.’

Professor Whitworth agrees that pregnant women should ‘think twice about going to anywhere in central or South America until the virus is under control’.