Zika virus: tests support links to birth defects and paralysis
'Everything we know about this virus seems to be scarier than we initially thought,' say officials
US health experts have confirmed that the Zika virus is the cause of severe birth defects, including microcephaly.
The condition, which causes children to have abnormally small heads, affected hundreds of babies born in Latin America last year, the rise in cases mimicking a spike in the number of people being infected by the Zika virus in the area.
Confirmation that the two are linked comes after signs of the virus were found in the brain tissue, spinal fluid and amniotic fluid of babies with microcephaly, reports The Guardian.
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"This study marks a turning point in the Zika outbreak. It is now clear that the virus causes microcephaly," said Dr Tom Frieden, the head of the US Centers for Disease Control and Prevention (CDC).
Experts hope the new findings will prompt greater public awareness about the virus, particularly among pregnant women.
"We've been very careful over the last few months to say, 'It's linked to', 'It's associated with.' We've been careful to say it's not the cause of," said Dr Sonja A Rasmussen, the director of public health information at the centre. "I think our messages will now be more direct."
Alongside the new statement, the CDC issued a stark warning that more public funding is needed to combat the disease.
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"Everything we know about this virus seems to be scarier than we initially thought," said the deputy director, Dr Anne Schuchat.
The confirmation will not affect the guidelines that health experts have issued over the virus, reports the BBC. Pregnant women have been told to avoid travelling to Zika-stricken regions, while those living in affected countries have been advised to use mosquito repellent and either abstain from sex or use condoms.
Zika virus: tests support links to birth defects and paralysis
18 February
The link between the mosquito-borne Zika virus and severe birth defects has been supported by a study carried out in Brazil.
The virus, which has spread to 30 countries and been declared a global health emergency by the World Health Organization (WHO), has coincided with a surge in babies born with microcephaly.
The causal link is yet to be confirmed, but scientists argue that the results "strengthen" the theory.
"The Zika virus [was] identified directly in the amniotic fluid of a woman during her pregnancy, suggesting the virus could cross the placental barrier and potentially infect the foetus," the lead scientist, Dr Ana de Filippis, from the Oswaldo Cruz Institute in Rio de Janeiro, told the BBC.
However, WHO assistant director genera Marie-Paule Kieny warns that more research is needed. "I think that we need a few more weeks and a few more studies to have this straight," she said.
Doctors in South and Central America also fear the Zika virus boosts susceptibility to the paralysing condition known as Guillain-Barre Syndrome. Eight countries have reported a rise in the rare and potentially fatal condition since the Zika outbreak began.
Scientists in Colombia say they are on the verge of confirming the virus is the cause of the auto-immune disorder after tests detected it in the blood of five patients with the syndrome.
"In my mind, it is related to Zika," neurologist Dr Andreas Zea told Sky News. "It is terrible. It's a mosquito - only one bite and 15, 20 days later, you are going to be in intensive care."
Zika virus: first US case was sexually transmitted
3 February
Health officials have confirmed that the first Zika virus contracted in the US was passed on through sexual contact.
So far, 31 people in the US have been diagnosed with the mosquito-borne virus, but the infected person, who has not been named, is believed to be the first to contract Zika without visiting one of the nations where the disease is running rampant.
"Now that we know Zika virus can be transmitted through sex, this increases our awareness campaign in educating the public about protecting themselves and others," Zachary Thompson, the director of Dallas County Health and Human Services, told Sky News.
He also stressed the importance of using condoms to prevent the spread of the disease.
Zika's symptoms are relatively mild and include sensitivity to light, joint pain and fever. The major concern is the virus's ability to infect the amniotic fluid of pregnant women, which can lead to birth defects. In affected countries, cases of microcephaly – a condition where a baby is born with an undersized head and brain – have increased sharply since the virus was first detected in May 2015. In the worst affected areas of Brazil, the BBC reports that one per cent of all newborns are diagnosed with microcephaly – nearly 4,000 infants in total.
Women in El Salvador have been advised to put off pregnancy until 2018 – a tall order in a nation where contraception is frowned upon and abortion totally outlawed. Similar advice has been issued in Colombia and Ecuador.
While cases of the Zika virus have been identified since the 1950s, the latest outbreak is becoming increasingly difficult to contain. The virus first appeared in May, in Brazil, and has since been detected in 35 countries in the Americas and Caribbean.
The World Health Organisation says the virus is "spreading explosively" and has declared a global public health emergency on the same scale as the Ebola outbreak that claimed more than 11,000 lives in West Africa between 2013 and 2016.
Zika virus: WHO declares global health emergency
02 February
A disease linked to the Zika virus constitutes a public health emergency of international concern, the World Health Organisation (WHO) has declared.
The virus, which has been spreading fast in Latin America since the turn of the year, is believed to be linked to a rise in cases of microcephaly, a disease that causes babies to be born with underdeveloped brains.
The decision places the virus in the same category of concern as the Ebola virus, which became a public health emergency in 2014.
WHO director general, Margaret Chan called Zika an "extraordinary event" that needed a co-ordinated response.
"I am now declaring that the recent cluster of microcephaly and other neurological abnormalities reported in Latin America following a similar cluster in French Polynesia in 2014 constitutes a public health emergency of international concern," she said.
The virus's effects are mild and cause few or no symptoms in adults, but it is believed the bigger health threat concerns unborn children.
Thousands of babies across Latin America have been born with abnormally small heads and the WHO's declaration will trigger research into these cases and the virus.
Currently, there is no vaccine or medication to stop Zika. The only way to avoid catching it is to avoid getting bitten by the Aedes mosquitoes that transmit the infection, reports the BBC.
The WHO has already warned that Zika is likely to "spread explosively" across nearly all of the Americas. More than 20 countries, including Brazil, are reporting cases.
Chan also spoke out against a travel ban to the affected areas.
"A knee-jerk response would be to ban travel and trade with countries affected, but the truth is that the potential problem is much wider," said Jonathan Ball, professor of molecular virology at Nottingham University. He told The Guardian: "It wouldn't really be feasible to lock down the affected countries to try to stop the spread of a virus that is carried by the Aedes mosquito, especially when affected and unaffected countries border one another."
The Brazilian government welcomed the WHO's declaration but said it would take researchers years to develop a vaccine.
"If we are really lucky, it could be three years, but it could be between three and five years," a spokesman told reporters.
Zika virus: threat has reached 'alarming proportions'
28 January
The World Health Organisation (WHO) has set up an emergency taskforce to respond to the Zika virus as experts warn the disease has "explosive pandemic potential".
The mosquito-borne virus isn't harmful to most people, but it has been linked to severe birth defects in babies. Women in affected areas have been urged to delay pregnancy until further notice.
The outbreak has spread to at least 23 countries in Latin America, with the WHO warning up to four million people could be infected this year. There is currently no known cure or vaccine.
"The level of alarm is extremely high," WHO director general Margaret Chan told a specially convened meeting in Geneva. "[It has gone] from a mild threat to one of alarming proportions."
Dr Carissa Etienne, the regional director for WHO's Pan American Health Organization, cautioned that the link between Zika and microcephaly in babies has not yet been confirmed, the BBC reports.
But she added: "We cannot tolerate the prospect of more babies being born with neurological and other malformations and more people facing the threat of paralysis."
The committee will convene on Monday to discuss whether or not to declare a global emergency. The last time this happened was in response to the Ebola outbreak in West Africa. The global health body has since faced widespread criticism for failing to respond soon enough to the crisis.