Zika virus: no vaccine, no cure

The incurable Zika virus is having devastating effects on unborn babies.

Dinkus - Katherine Towers

For the hundreds of thousands of pregnant women across Latin America and the Caribbean, the warning came too late.

With the incurable mosquito-borne Zika virus sweeping across Brazil, El Salvador and Colombia and now threatening the US, they face an agonising wait and the prospect of every new mother’s worst nightmare; delivering a severely disabled child, or worse, one that is dead.

The effects of the Zika virus on adults are mild, almost undetectable, but for the unborn, they are devastating.

Since October, nearly 4000 Brazilian babies have been delivered with suspected microcephaly, a foetal deformation that limits brain development, leading to babies with abnormally small heads.

Authorities believe their mothers were infected with Zika during the first trimester of pregnancy and while not definitive, have linked a massive increase in severe birth defects in the region to the virus.

Fifty babies have died and the toll is expected to rise. An unknown number of foetuses with the condition have miscarried, and the babies that have survived face a lifetime of developmental and health problems.

Now, millions of women across the region have been warned not to fall pregnant as authorities scramble to contain the biggest health risk since the 2014 West Africa ebola crisis.

And, given the outbreak is centred on Brazil, where the world famous Carnivale will burst into life next week, not to mention the Olympic Games in about six months, concerns have instantly gone global.

“The scant and misleading information that there is out there made me and my husband change our mind about getting pregnant,” a 40-year-old woman who had been about to have IVF, told O Dia, a newspaper based in Rio de Janeiro.

And, virologists warn, Australia is not immune.

Here, six people tested positive for the Zika virus last year, all infected while overseas. This follows a mini-breakout of 12 cases diagnosed in 2014 and only one in 2013.

The Australian government has been quick to act on the latest threat, issuing a travel warning to Australians, particularly pregnant women, to reconsider plans to travel to 22 countries affected by the virus, including many in South and Central America and also the Pacific island nations of Samoa and Vanuatu.

The travel advice comes in response to a warning by the World Health Organisation that Zika is spreading to all countries in South, Central and North America, except Canada and Chile.

While no birth defects from the disease have yet been reported in the mainland US, a woman who fell ill with the virus in Brazil later gave birth to a brain-damaged child in Hawaii.

Last week in Florida, three US residents returned from Venezuela and Colombia with Zika. And three British travellers returning from Colombia, Suriname and Guyana have also been found to have the disease. In many ways, authorities are responding in the dark.

There is little scientific data on the Zika virus and why it might cause foetal deformation. There is no vaccine and no cure.

A majority of adults affected experience no symptoms and if they do, they are almost flu-like with a fever, tiredness, headaches and joint and muscle pain.

Before 2013 only a handful of Zika cases had been recorded around the world but last year, the disease spread rapidly.

It is transmitted by some species of Aedes mosquito, particularly the Aedes aegypti, and it is reportedly closely related to dengue, yellow fever and the West Nile viruses.

But why the disease has led to a sudden spate of birth defects has authorities baffled.

Also uncertain: how mosquitoes themselves are infected.

Dominic Dwyer, a virologist from Sydney’s Westmead Hospital, told the ABC that the 80 per cent of adults who are infected experience no symptoms with the virus clearing from their blood within a week.

There is still “uncertainty” surrounding whether or not Zika was actually responsible for the brain damage in newborns, Dwyer says.

He plays down the risk to Australia, saying scientists were not even sure if local mosquitoes could be vectors of the virus.

“There have been some people who have come back to Australia who’ve had the Zika virus infection,” he says.

“But what we haven’t had is evidence of the spread of the infection from one person to another in this country.

“The main mosquito carriers of the virus are not present to any great degree in Australia, except perhaps up in the top end of Queensland. But we’re not entirely sure yet whether some of the Australian mosquitoes could carry Zika virus.

“So, I think there’s a bit more work to be done to sort that out.”

Yet Dwyer warns that the risk to Australia should be taken seriously and that it is a matter of being “alert but not alarmed”.

“When you get a virus go into a population where the people aren’t immune, then you often get very rapid spread.

“So for example over the last decade there have been a number of islands in the Pacific that have had explosive outbreaks of Zika virus infection, as well as others like Chikungunya virus.

“So when the virus gets in there and you’ve got the right mosquitoes — vectors to carry the virus — then the population aren’t immune, so the transmission in the community can be really rapid.”

And in a blunt message to women who are pregnant, or even think they are pregnant, he said it would be “foolish” to go to the region until authorities could determine if and how the virus was causing birth defects.

The virus was first detected in a monkey in the Zika forest near Lake Victoria in Uganda in 1947, but it was not until the 1960s that the first human cases were identified in Nigeria.

Outbreaks have previously been reported in tropical Africa, Southeast Asia and the Pacific Islands.

Samoa has reported Zika for the first time and officials in Vanuatu are on high alert after an outbreak last April.

While Zika is not as deadly as ebola and, so far, cannot be transferred from human to human, concern is growing among international experts that it is evolving, or that a mutation led to the recent devastating effects on unborn babies.

But, like the recent ebola outbreak, the spread of the disease has kept ahead of international attempts to contain it. Brazil’s health minister admitted earlier in the week that the country was “losing the battle”.

Nearly 220,000 members of Brazil’s armed forces are set to go door to door ahead of the country’s Carnivale celebrations next week, in a mass-mosquito eradication effort, while Colombian President Juan Manuel Santos has predicted 700,000 cases in that country alone by the end of the year.

Pregnant women are hoarding mosquito repellent, refusing to go outdoors and shunning dark clothes in a desperate attempt to avoid being bitten by mosquitoes.

World Health Organisation ­director-general Margaret Chan describes the spread of the disease as “explosive” due to the population’s poor immunity and was likely to reach all countries and territories where the Aedes mosquitoes are found.

While doctors are looking into whether the disease can be ­sexually transmitted, the Latin American epidemic has generally been blamed on chaotic urban growth, underfunded health ­services and the widespread use of plastics which trap rainwater and provide breeding grounds for the potentially deadly mosquitoes.

As well as dealing with public panic over the epidemic, officials in Brazil are desperately trying to play down the long-term threat as thousands of athletes from around the world are due to converge on Rio later in the year for the summer Olympics

On Tuesday, fumigators in Rio were sent military-style into the city’s carnivale stadium which in August is due to be used for Olympic archery.

The sight of men in protective overalls and goggles spraying the famous Sambadrome facility was a grim confirmation of just how worried Brazil is the virus will tarnish the games.

The chief medical officer of the Australian Olympic team says he has been monitoring the outbreak and will put out a health advisory to each potential team member warning them of the risks of contracting the disease.

The Australian Olympic Committee’s medical team has spent three years assessing the risk of mosquito-borne diseases in Brazil, but it admits the outbreak of Zika took them by surprise.

The AOC is advising all team members to wear covering clothing, use insect repellent and avoid areas, like jungles, where mosquitoes are likely to breed.

“We are not expecting that there will be many if any pregnant members of the team but we will be very cautious about that,” Dr Hughes says.

The warnings on pregnancy are more likely to be relevant to the family and friends of Australia’s Olympians, he says.

The Rio Games organisers are relying on cooler weather and less rain in August and assure competing countries that they will fumigate all venues if needed.

A spokesman for the US Olympic Committee says it too is watching events in Brazil closely and relying on the US-based Centres for Disease Control and Prevention for ongoing advice.

The CDC says it will post specific guidance reports about the Zika epidemic closer to the Games and that it is still monitoring the “evolving” situation.

The British Olympic Association is closely monitoring the situation and says it will also be releasing specific information closer to the event.

With uncertain commercial prospects, large pharmaceutical companies have been reluctant to invest in vaccines for tropical diseases.

Health experts are calling for a new system of incentives for drug makers to research and develop vaccines, particularly in light of the deadly Ebola outbreak two years ago.

The Sao Paulo-based Butantan Institute is leading the world on research into the virus and it has been reported as having plans to develop a vaccine in “record time”, it that means it would still be unavailable for between three and five years.

Again, too late, for the pregnant women of Latin America.

ADDITIONAL REPORTING: THE TIMES AND ASSOCIATED PRESS