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[genet-news] POLICY & REGULATION: Three million GE mosquitoes released in Cayman Islands



                                  PART 1


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TITLE:   MUTANT MOSQUITOES FIGHT DENGUE IN CAYMAN ISLANDS

SOURCE:  The Associated Press, USA

AUTHOR:  

URL:     http://www.google.com/hostednews/ap/article/ALeqM5iJg3GFfMS2oAMzerUoes59s_o6ZQ?docId=e53509adbb294717a33deb7a1ae3e9dd

DATE:    11.11.2010

SUMMARY: "Scientists have released genetically modified mosquitoes in an experiment to fight dengue fever in the Cayman Islands, British experts said Thursday. It is the first time genetically altered mosquitoes have been set loose in the wild, after years of laboratory experiments and hypothetical calculations. But while scientists believe the trial could lead to a breakthrough in stopping the disease, critics argue the mutant mosquitoes might wreak havoc on the environment."

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MUTANT MOSQUITOES FIGHT DENGUE IN CAYMAN ISLANDS

LONDON (AP) ? Scientists have released genetically modified mosquitoes in an experiment to fight dengue fever in the Cayman Islands, British experts said Thursday.

It is the first time genetically altered mosquitoes have been set loose in the wild, after years of laboratory experiments and hypothetical calculations. But while scientists believe the trial could lead to a breakthrough in stopping the disease, critics argue the mutant mosquitoes might wreak havoc on the environment.

"This test in the Cayman Islands could be a big step forward," said Andrew Read, a professor of biology and entomology at Pennsylvania State University, who was not involved in the project. "Anything that could selectively remove insects transmitting really nasty diseases would be very helpful," he said.

Dengue is a potentially fatal mosquito-borne disease that can cause fever, muscle and joint pain, and hemorrhagic bleeding. More than 2.5 billion people are at risk and the World Health Organization estimates there are at least 50 million cases every year. There is no treatment or vaccine.

Unlike malaria, which is also spread by mosquitoes, dengue outbreaks are unpredictable and bed nets are of limited use because dengue-spreading mosquitoes also bite during the day.

Researchers at Oxitec Limited, an Oxford-based company, created sterile male mosquitoes by manipulating the insects' DNA. Scientists in the Cayman Islands released 3 million mutant male mosquitoes to mate with wild female mosquitoes of the same species. That meant they wouldn't be able to produce any offspring, which would lower the population. Only female mosquitoes bite humans and spread diseases.

>From May to October, scientists released batches of genetically mutated male mosquitoes in cages three times a week in a 40-acre (16-hectare) area. By August, mosquito numbers in that region dropped by 80 percent compared with a neighboring area where no sterile male mosquitoes were released.

Luke Alphey, Oxitec's chief scientific officer, said with such a small area, it would have been very difficult to detect a drop in dengue cases. But their modeling estimates suggested an 80 percent reduction in mosquitoes should result in fewer dengue infections.

For years, scientists have been working to create mutant mosquitoes to fight diseases like malaria and dengue, which they say could stop outbreaks before they start. But, others suspect it could be an environmental nightmare.

"If we remove an insect like the mosquito from the ecosystem, we don't know what the impact will be," said Pete Riley, campaign director of GM Freeze, a British non-profit group that opposes genetic modification.

He said mosquito larvae might be food for other species, which could starve if the larvae disappear. Or taking out adult mosquito predators might open up a slot for other insect species to slide in, potentially introducing new diseases.

Humans have a patchy track record of interfering with natural ecosystems, Riley said. In the past, such interventions have led to the overpopulation of species including rabbits and deer. "Nature often does just fine controlling its problems until we come along and blunder into it."

Oxitec's Alphey said their genetically modified mosquitoes can't permanently change the ecosystem because they only last for a generation. But to stamp out dengue in endemic areas like Asia and South America, billions of the special-order mosquitoes would likely be needed to stifle their wild counterparts.

Yeya Toure, who leads the World Health Organization's team on Innovative Vector Control Interventions, called the Cayman Islands trial promising and said it's worth continuing the genetic modification experiments.

He said genetically altered mosquitoes aren't meant to replace existing tools like insecticides, but to compensate for their limitations, like when mosquitoes develop resistance.

Read said creating mutated mosquitoes might actually be the least invasive way to control dengue. By keeping a lid on the mosquito population via genetic modification, Read said entire ecosystems would be spared the toxic effects of indiscriminately spraying pesticides.

He said the bigger problem would be selling the idea of genetically altered mosquitoes to the public. In the Cayman Islands, officials said they worked closely with the local community and encountered surprisingly little resistance.

"We still have people who don't believe in vaccines," Read said. "How are we going to convince them it's OK to let scientists release genetically altered mosquitoes into the wild?"



                                  PART 2

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TITLE:   STERILE MOSQUITOES USE SEX TO KILL IN DENGUE TRIAL

SOURCE:  Thomson Reuters, USA

AUTHOR:  Kate Kelland

URL:     http://www.reuters.com/article/idUSTRE6AA3M420101111

DATE:    11.11.2010

SUMMARY: "British scientists have created genetically sterile mosquitoes which use sex to kill off others in their species, and researchers say early field trials suggest the idea could help to halt the rapid spread of dengue fever. Scientists from a firm called Oxitec ran a small trial with the Mosquito Research and Control Unit (MRCU) in the Cayman Islands in the Caribbean. This found that releasing 3 million of the genetically altered bugs into a small area managed to cut the species population by 80 percent in six months."

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STERILE MOSQUITOES USE SEX TO KILL IN DENGUE TRIAL

LONDON (Reuters) - British scientists have created genetically sterile mosquitoes which use sex to kill off others in their species, and researchers say early field trials suggest the idea could help to halt the rapid spread of dengue fever.

Scientists from a firm called Oxitec ran a small trial with the Mosquito Research and Control Unit (MRCU) in the Cayman Islands in the Caribbean. This found that releasing 3 million of the genetically altered bugs into a small area managed to cut the species population by 80 percent in six months.

Dengue fever, a disease which causes severe flu-like symptoms and can kill, is spread through the bite of infected female Aedes aegypti mosquitoes.

"The idea is based on releasing sterile males who will go out and mate with wild females," said Luke Alphey, Oxitec's chief scientist and co-founder.

"One of the main advantages is that the males actively look for the females -- that's what they are programed to do."

Larvae are produced but most die before they hatch and the rest survive only a short time as mosquitoes.

The World Health Organization estimates there are 50 million cases of dengue fever a year, of which 25,000 are fatal, and about 2.5 billion people -- two-fifths of the world's population -- are at risk, mostly in Africa and southeast Asia.

There is no vaccine or treatment for dengue, and experts say innovative ways of dealing with its spread are urgently needed, since global incidence has risen sharply in recent decades.

French drugmaker Sanofi-Aventis is one of various groups seeking to develop dengue vaccines. It is testing its candidate in late stage clinical trials, but experts say it could be many years before a vaccine is on the market.

Alphey's team bred a version of the male Aedes aegypti mosquito which can attract and mate with females but is genetically modified to die if it is not fed on a certain antidote, in this case an antibiotic called tetracycline.

"We put a segment of DNA into the mosquito which means it will die unless it gets the antidote," said Alphey told reporters at a briefing in London on Thursday.

"By giving them tetracycline in the lab, we can keep them alive and breed large numbers of them, but when we release the males into the environment and they mate with wild females, all the offspring inherit a copy of the gene that kills them if they don't get the antidote...so they die."

Most of the offspring die as larvae, he said, but even those who manage to hatch face a very short life.

Angela Harris of the Cayman MRCU, said she was very encouraged by the results of the trial, which was conducted and monitored during April to October this year.

"This kind of technology really has a place for reducing dengue and having an impact on human health," she said.

"One of dengue's main problems is that there's no cure, there's no vaccine and there are no drugs you can take to avoid it or get better from it. So the only control you can really come by ... is killing the mosquitoes and making sure they're not there to transmit the virus in the first place."

Alphey said his Oxford-based firm is in talks with officials in various countries, including Malaysia, Brazil and Panama about conducting further and larger trials.



                                  PART 3

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TITLE:   DENGUE FEVER A RISK FOR 2.5 BILLION PEOPLE

SOURCE:  Thomson Reuters, USA

AUTHOR:  Factbox

URL:     http://www.reuters.com/article/idUSTRE6AA3MQ20101111

DATE:    11.11.2010

SUMMARY: "British scientists have created genetically sterile mosquitoes who use sex to kill off others in their species and researchers say early field trials suggest the idea could help halt the spread of dengue fever."

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DENGUE FEVER A RISK FOR 2.5 BILLION PEOPLE

(Reuters) - British scientists have created genetically sterile mosquitoes who use sex to kill off others in their species and researchers say early field trials suggest the idea could help halt the spread of dengue fever.

Here are some facts about dengue fever:

* Dengue is transmitted by the bite of an Aedes aegypti mosquito infected with any one of the four dengue viruses. Symptoms appear in 3 to 14 days after the infective bite.

* Dengue fever is a severe, flu-like illness that affects babies, young children and adults.

* It is often known colloquially as bone-break fever for the severe muscle and joint pains it induces, the disease causes death only when it develops into a more severe form, dengue haemorrhagic fever.

* Early clinical diagnosis of dengue haemorrhagic fever and careful clinical management by experienced doctors and nurses often saves lives.

* Global incidence of dengue has grown dramatically in recent decades.

* Around 2.5 billion people -- two fifths of the world's population -- are now at risk from dengue. The World Health Organization (WHO) currently estimates there may be 50 million dengue infections worldwide every year.

* With no specific treatment for the four viruses, health officials focus on eradicating mosquitoes to prevent infections.

* More than 70 percent of the disease burden is in southeast Asia and the western Pacific area. Africa and the Eastern Mediterranean are much less affected.

* According to the WHO, the incidence and severity of disease are increasing rapidly in Latin America and the Caribbean.

* An increase in international air travel is facilitating the rapid global movement of dengue viruses. This increases the risk of dengue haemorrhagic fever epidemics by introducing new dengue viruses into susceptible populations.

* French drugmaker Sanofi-Aventis is one of various groups and firms seeking to develop a dengue vaccine and is currently testing it in late stage clinical trials.

SOURCE: Reuters/World Health Organization.



                                  PART 4

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TITLE:   OPEN FIELD TRIAL DEMONSTRATES EFFECTIVENESS OF RIDL® SYSTEM FOR SUPPRESSING A TARGET WILD MOSQUITO POPULATION

SOURCE:  Oxitec, UK

AUTHOR:  Press Release

URL:     http://db.zs-intern.de/uploads/1289498625-Oxitec-MRCU-press-release.pdf

DATE:    04.11.2010

SUMMARY: "Oxitec and the Mosquito Research and Control Unit of Grand Cayman (MRCU) today announced, at the American Society of Tropical Medicine and Hygiene annual meeting in Atlanta, the results of their open field trial. This was the first field demonstration of the use of Oxitec?s RIDL strain OX513A to control the dengue-carrying Aedes aegypti mosquito. "

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OPEN FIELD TRIAL DEMONSTRATES EFFECTIVENESS OF RIDL® SYSTEM FOR SUPPRESSING A TARGET WILD MOSQUITO POPULATION

Oxitec and the Mosquito Research and Control Unit of Grand Cayman (MRCU) today announced, at the American Society of Tropical Medicine and Hygiene annual meeting in Atlanta, the results of their open field trial. This was the first field demonstration of the use of Oxitec?s RIDL strain OX513A to control the dengue-carrying Aedes aegypti mosquito. 

This genetically sterile mosquito strain has been developed to help combat the dengue carrying mosquito Aedes aegypti. This sterility can be suppressed with a dietary antidote, allowing the strain to be reared in large numbers. Sterile males are then released to seek out and mate wild females, competing for mates with the wild males. If a female mates with a sterile male she will have no offspring, thus reducing the next generation's population. Repeated releases of sufficient numbers of sterile males will result in a reduction in the target mosquito population below the minimum level needed to support dengue transmission. 

Male mosquitoes do not bite or spread disease and will mate only with females of the same species, hence the release of sterile male mosquitoes presents a safe alternative to insecticides. 

Dr William Petrie of MRCU said ?Dengue is a debilitating disease one can only get from the bite of an infected mosquito. There are around 100 million cases per annum globally and we need new tools against this mosquito?, a view supported by the World Health Organisation; ?the only way to prevent dengue virus transmission is to combat the disease-carrying mosquitoes.?1 

The field trial took place in Grand Cayman with sterile male releases from May to October and additional pre- and post-trial monitoring. This followed a successful smaller trial in 2009 that demonstrated that released RIDL males mated successfully with their local counterparts in the open environment. Eggs were supplied from Oxitec?s facilities in the UK and the sterile male mosquitoes were hatched and released by MRCU. After initial production and release testing, releases of male sterile mosquitoes reached the required release level in July. A significant reduction in the local mosquito population was observed from August. All of the trial objectives were successfully met, including the main goal of suppressing the local Aedes aegypti population. 

Dr Luke Alphey, Chief Scientific Officer and Founder of Oxitec added ?Oxitec considers that this approach could be used in many countries to help control the Aedes aegypti mosquito and hence prevent dengue fever. We have been working on this for many years to ensure the approach is both effective and safe. This trial represents the first demonstration in the open field and we are delighted with the results.? 

About Dengue Oxitec Limited Oxitec Limited, 71 Milton Park, Abingdon, Oxfordshire OX14 4RX T 01235832393 F 01235861138 E info@oxitec.com www.oxitec.com Registered office 2nd Floor Park Gate, 25 Milton Park, Oxford OX14 4SH Registered number 4512301 

Dengue is the world?s fastest growing mosquito borne viral disease for which there is neither medication nor vaccine. Existing control methods centre on the use of insecticides together with practical methods to reduce the number of likely mosquito breeding sites. Despite this, dengue fever has grown rapidly over the last decades as Aedes aegypti has spread to new countries and, according to the WHO, two fifths of the world?s population, some 2.5bn people, are now at risk. 

About Oxitec 

Oxitec is a pioneer in controlling insects that spread disease and damage crops. Oxitec has developed RIDL technology that allows the development of sterile males of a target insect species as a control method. This approach is safe, environmentally friendly and sustainable. 

About MRCU 

The Mosquito Research & Control Unit (MRCU) was established in 1965 and provides mosquito control on Grand Cayman and its sister islands. MRCU also performs leading research into mosquito behaviour, insecticide resistance and control methods and is internationally renowned for its public health contribution. 

1 WHO Dengue factsheet http://www.who.int/mediacentre/factsheets/fs117/en/index.html




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