Are GM mosquitoes the key to wiping out the Zika virus? Brazil set to use engineered bugs to eradicate 'brain-shrinking' disease

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As the world struggles to contain the spread of the 'brain-shrinking' Zika virus, and scientists work on a vaccine, a British biotech firm has suggested an alternative way to curb the disease. 

Oxitech has been genetically modifying mosquitoes in its lab in Oxford that have been engineered in such a way that means their offspring die before reaching maturity. 

Scientists are now planning to release these bugs in Brazil, and potentially other problem areas, in the hope that if the males breed with enough females, the populations will, in theory, be wiped out. 

Oxitech has been genetically modifying mosquitoes in its lab in Oxford that have been engineered in such a way that means their offspring die before reaching maturity. Scientists are now planning to release these bugs in Brazil in the hope that if the males breed with enough females, the populations will, in theory, be wiped out 

Brazil is the latest country to approve the use of these engineered bugs.  

The South American nation has been scrambling to contain the spread of Zika, which has been linked to a recent surge in birth defects including microcephaly - a rare condition in which newborns have smaller than normal heads and their brains do not develop properly.

In a statement, Oxitec said tests that began in April 2015 have shown that the release of genetically modified sterile male mosquitoes succeeded in reducing a variety of disease-transmitting mosquito larvae by 82 per cent by year's end in a neighborhood of the city of Piracicaba.

Piracicaba's city health department confirmed the tests and results. 

In a statement, Oxitec said tests that began in April 2015 have shown that the release of genetically modified sterile male mosquitoes succeeded in reducing a variety of disease-transmitting mosquito larvae by 82% by year's end in the city of Piracicaba. Piracicaba's city health department confirmed the tests and results

The Zika virus was first discovered in a monkey in Uganda in 1947 - its name comes from the forest where it was first discovered. The World Health Organisation said Zika is rapidly spreading in the Americas because it is new to the region, people aren't immune to it, and the mosquito that carries it is just about everywhere

The Aedes aegypti mosquito (pictured) is responsible for spreading Zika. It also transmits dengue fever and chikungunya. The genetically modified, male mosquitoes themselves don't spread disease because only the females bite

The Aedes aegypti mosquito is responsible for spreading Zika. It also transmits dengue fever and chikungunya.

The genetically modified, male mosquitoes themselves don't spread disease because only the females bite.

Joseph Conlon, a technical adviser for the American Mosquito Control Association, called the results 'novel and potentially efficacious.'

Conlon said the procedure is not 100 per cent effective, but if it is allowed to proceed to full measure, it will 'reduce the mosquito population below disease transmission levels with minimal effect on the environment.'

He added that the Aedes aegypti 'are notoriously difficult to control by conventional spray methods such as truck or aerial sprays.'

The Brazilian army has been helping in efforts to control the mosquito population by eliminating standing water.

Most of the 3,530 babies the Health Ministry said have been born with microcephaly in the country since October have been concentrated in the country's poorest regions, such as the northeast. 

But worries about Zika have prompted residents in wealthier cities such as Rio de Janeiro and Sao Paulo to stock up on mosquito repellent.

Fewer than 150 cases of microcephaly were seen in all of 2014.

In Brazil, there has been mounting evidence linking Zika infection in pregnant women to a rare birth defect called microcephaly, in which a newborn's head is smaller than normal (spictured) and the brain may not have developed properly. Brazilian officials noticed a spike in cases of microcephaly in tandem with the outbreak

But what exactly is Zika and what are the risks of travelling to the affected area? Here, we reveal everything you need to know about the virus...

WHAT IS ZIKA?

The Zika (ZEE'-ka) virus was first discovered in a monkey in Uganda in 1947 - its name comes from the Zika forest where it was first discovered. 

It is native mainly to tropical Africa, with outbreaks in Southeast Asia and the Pacific Islands. It appeared in Brazil last year and has since been seen in many Latin American countries and Caribbean islands.

HOW IS IT SPREAD?

It is transmitted through bites from the same kind of mosquitoes that can spread other tropical diseases, like dengue fever, chikungunya and yellow fever. 

It is not known to spread from person to person. 

Investigators, though, are exploring the possibility that the virus can be passed on through sex - it was found in one man's semen in Tahiti and there's been another report of possible spread of the virus through sex.

An Aedes Aegypti mosquito on human skin in a lab in Cali, Colombia. Scientists there are studying the genetics and biology of this mosquito, which transmits the Zika virus

The World Health Organisation says Zika is rapidly spreading in the Americas because it is new to the region and people are not immune to it. Furthermore, the Aedes aegypti mosquito (pictured) that carries it is just extremely widespread

The World Health Organisation says Zika is rapidly spreading in the Americas because it is new to the region, people aren't immune to it, and the Aedes aegypti mosquito that carries it is just about everywhere - including along the southern United States. 

Canada and Chile are the only places without this mosquito.

ARE THERE SYMPTOMS?

Experts think most people infected with Zika virus don't get sick. 

And those that do usually develop mild symptoms - fever, rash, joint pain, and red eyes - which usually last no more than a week. 

There is no specific medicine and there hasn't been a vaccine developed for it, which is the case for some other tropical illnesses that cause periodic outbreaks.

WHY IS IT A CONCERN NOW?

In Brazil, there has been mounting evidence linking Zika infection in pregnant women to a rare birth defect called microcephaly, in which a newborn's head is smaller than normal and the brain may not have developed properly. 

Brazilian health officials last October noticed a spike in cases of microcephaly in tandem with the Zika outbreak. 

The connection to Zika is still being investigated, and officials note there are many causes of the condition. Nearly 4,000 cases have been recorded.

Meanwhile, doctors have noted increased reports of a nerve condition called Guillain-Barre that can cause paralysis. 

But the link to the Zika virus is not clear; other infections can spark the problem, including dengue fever.

CAN THE SPREAD BE STOPPED?

Individuals can protect themselves from mosquito bites by using insect repellents, and wearing long sleeves and long pants - especially during daylight, when the mosquitoes tend to be most active, health officials say. 

Eliminating breeding spots and controlling mosquito populations can help prevent the spread of the virus.

HAVE THERE BEEN CASES IN THE US?

Yes, but in tourists. Since 2007 there have been more than two dozen cases diagnosed in the US all travellers who are believed to have caught it overseas. 

(Puerto Rico and the U.S. Virgin Islands have each had a recent case that didn't involve a traveler.)

There is no vaccine or treatment for Zika, which typically causes mild fevers and rashes, although about 80 per cent of those infected show no symptoms 

The kind of mosquito that spreads Zika is found along the southern states, so experts think it's likely the pests may end up spreading the virus there. 

But officials also have said Zika infections probably won't be a big problem in the US for a number of reasons, including the more common use of air conditioning and door and window screens. 

Recent U.S. outbreaks of dengue and chikungunya - carried by the same mosquito - suggest any Zika outbreaks may be relatively small, said Dr. Lyle Petersen of the Centers for Disease Control and Prevention. 

WHAT ARE THE TRAVEL ADVISORIES?

US health officials recommend that pregnant women should consider postponing trips to 22 destinations. Latin America: Bolivia, Brazil, Colombia, Ecuador, El Salvador, French Guiana, Guatemala, Guyana, Honduras, Mexico, Panama, Paraguay, Suriname and Venezuela. In the Caribbean: Barbados, Guadeloupe, Haiti, Martinique, St. Martin and Puerto Rico. Also, Cape Verde, off the coast of western Africa; and Samoa in the South Pacific.

In Brazil, most of the mothers who had babies with microcephaly were apparently infected during the first trimester, but there is some evidence the birth defect can occur later in the pregnancy, CDC officials say. 

The travel alert applies to women in any stage of pregnancy.