Scientists create GM mosquitoes to fight malaria and save thousands of lives

- Plan to breed and sterilise millions of male insects
- Leader says project almost ready for testing in wild

Genetically modified mosquitoes could soon be released into the wild in an attempt to combat malaria. Scientists at Imperial College London, who created the GM insects, say they could wipe out natural mosquito populations and save thousands of lives in malaria-stricken regions.

Led by Andrea Crisanti, the team added a gene that makes the testicles of the male mosquitoes fluorescent, allowing the scientists to distinguish and easily separate them from females. The plan is to breed, sterilise and release millions of these male insects so they mate with wild females but produce no offspring, eradicating insects in the target region within weeks.

Professor Crisanti said: "Our mosquitoes are nearly ready for testing in the wild. This is a technology that works and could make a real difference. The beauty is that it's very specific. Unlike insecticides, sterile males target only the species you want to attack."

Mosquitoes that spread malaria have long been a target for sterile male technology, which has been used to eradicate the screwworm fly from the US, Mexico and Central America.

The International Atomic Energy Agency has been using its radiation technology to support health projects, and wants to release sterile mosquitoes to tackle malaria in northern Sudan and on Reunion island in the Indian ocean - but they and other groups have been hampered by an inability to distinguish the males, which do not bite people. Female mosquitoes transmit malaria, even if sterile, so releasing them alongside males would make the situation worse.

Prof Crisanti said: "The really challenging problem is to identify the males. There is no difference between the larvae and as adults they fly, so the logistics of trying to separate them when they're adults is immense."

To solve the problem, his team altered the DNA of the mosquito species Anopheles stephensi, the principal carrier of malaria in Asia, so that the males expressed a fluorescent green protein in their sperm. A sorting machine based on laser light separated male from female larvae, according to whether they glowed or not. Writing in Nature Biotechnology today, the scientists say the machine could sort 180,000 larvae in 10 hours.

The next step is to scale up the technique to provide the millions of GM insects needed to make a large-scale release effective. The scientists also need to check the sterile males will be strong enough to compete with wild rivals when released - the strategy depends on female mosquitoes, who only mate once in their two-week lifespan, choosing sterile males.

Prof Crisanti said other mosquito species could be modified in the same way, including Anopheles gambiae, which is responsible for a large part of the 2.7m deaths caused by malaria each year. He is talking to international agencies about setting up a trial. Scientists have previously considered releasing both male and female mosquitoes that have been genetically modified in a different way, making them unable to transmit malaria. The idea is that altered insects would spread the disruptive genes through natural mosquito populations, but concerns about whether the inserted genes could transfer to other organisms have so far scuppered plans to set up large-scale breeding colonies to test it.

Prof Crisanti argued that, because the new GM mosquitoes are sterilised, releasing them into the environment does not pose significant risks: "It won't transmit any genes to the environment. This allows us to test the transgenic technology in a very safe way that overcomes the previous environmental and safety concerns." Releasing males only would ensure people were not bitten by GM mosquitoes, he added.

Sue Mayer of Genewatch agreed that the new GM insect did address some of the previous concerns, but she called for thorough testing of the mosquitoes before they were considered for release. "Changing one gene can sometimes affect others, so there are still questions to ask," she said.

There are political barriers too. The London group's insect is best suited to tackling malaria in impoverished urban areas of south-east Asia and India, where World Health Organisation trials of sterile male mosquitoes to fight dengue fever collapsed in the 1970s amid biowarfare accusations. The males of the mosquito involved in the Delhi trials could be separated because their pupae were smaller, but they were never released after newspaper articles claimed the experiment might secretly be used to gather data on how to spread yellow fever.

Chris Curtis, a malaria expert with the London School of Hygiene and Tropical Medicine who worked on the WHO project in India, said: "We were all set to go and there was a huge uproar. You have to handle the public relations very carefully."

Female mosquitoes can travel several kilometres after mating, he said, so the sterile male technique is best suited to isolated insect populations, such as in cities. "If females that have already mated fly in from outside your release area then they carry on laying fertile eggs. That's fatal."

The world's most common and deadly parasitic disease. It is spread from person to person when female mosquitoes feed on human blood. Infects up to 500 million people each year, and kills an estimated 2.7 million people.

Male insects can be sterilised using chemicals and radiation. If enough sterile males can be released to breed with females, the insect population of a target region can crash within weeks.

Originally identified in jellyfish that live in the cold waters of the north Pacific ocean. The protein glows green under ultraviolet light.

Huge numbers of sterile males would have to be released, possibly several hundred thousand at different locations throughout a city in several waves over a month.

The disease was absent from Asia but appeared on a US list of potential biowarfare agents. When an Indian journalist discovered the common name of the insect involved was "yellow fever mosquito" the trials were halted.

Why The Insecticide DDT Should Never Have Been Banned
'Green errors began with DDT' by Christopher Pearson
The Weekend Australian, January 24, 2004
To many, the green movement still seems a harmless enough nature cult, not to be taken too seriously. But evidence and arguments have been emerging to suggest otherwise with increasing momentum and effect. The environmental lobby now stands charged with direct responsibility for millions of needless deaths, mostly of children in the Third World, from malaria.

At issue is the banning of DDT. Bjorn Lomborg, of The Skeptical Environmentalist fame; puts the basic science briskly.

"Our intake of coffee is about 50 times more carcinogenic than our intake of DDT before it was banned...the cancer risk for DDT is about 0.00008 per cent."
Ted Lapkin insists in November's edition of Quadrant that it's "still widely regarded as the single most powerful weapon at our disposal in the war against malaria" and that its disuse has been a scandal of public policy. Author Michael Crichton, in an address to the Commonwealth Club in San Francisco, claimed that
"banning DDT is one of the most disgraceful episodes in the 20thcentury history of America".
The junkscience.com website sees the ban as a tool for First World bureaucrats to pursue the goal of zero population growth in the developing world.
DDT was banned after Rachel Carson, in Silent Spring (1962), accused it of a range of dangers to human health (notably cancer), to the ecosystem and to thinning the eggshells of bald eagles. Lapkin cites plausible authority that

"no scientific peer-reviewed study has ever replicated any case of negative human health impacts from DDT".
He asserts that of all Carson's charges "the only contention that has been scientifically proved is the thinning effect DDT has on the eggshells of predatory birds".
The scientific and moral crux is that the relative harmlessness of DDT has long been established. One late-1950s study involved researchers feeding a man 35mg of DDT a day for two years with no ill effects. Lapkin quotes Donald Roberts, an eminent professor of tropical medicine, as saying:

"You could eat a spoonful of it and it wouldn't hurt you".
Why then did the US Environmental Protection Agency ban DDT in 1972? The simple answer is that the environmental movement spawned by Carson's catastrophic predictions prevailed over empirical research. Far worse is Crichton's terrible charge:
"We knew better and we did it anyway, and we let people around the world die and didn't give a damn."
According to junkscience.com, a population control official at the Agency for International Development blithely summed it up as "rather dead than alive and riotously reproducing".
Analysing the potency of green campaigns, Crichton says "our past record of environmental action is discouraging, to put it mildly...But we do not recognise our past failures and face them squarely. And I think I know why...today, one of the most powerful religions in the Western world is environmentalism. [It] seems to be the religion of choice for urban atheists."

Crichton's very persuasive argument is that ecological pieties are just that; religious convictions immune to rational scrutiny. "The question is whether you are going to be one of the people on the side of salvation or on the side of doom. Whether you are going to be one of us, or one of them." Compared with such vitally important definers of personal identity, what do outcomes vaguely apprehended (if at all ), let alone distant deaths, matter?

A suggestive irony is that the industrialised world had eradicated malaria at home, and got the benefits of DDT, before banning it and campaigning to have it banned elsewhere. As well, the leadership of Greenpeace and the World Wildlife Fund unconscionably turned a blind eye "to an African malaria catastrophe that was a direct outgrowth of their own advocacy", according to Lapkin. The cost —

"millions of human lives each year...a completely preventable epidemic...Greenpeace is currently campaigning to shut down the only facility in India that still manufactures DDT".
Non-government organisations worked hand in glove with nation states. The international development agencies of Norway and Sweden, where the anopheles mosquito has never posed a problem, refused to fund programs using DDT because they had banned its domestic use. How many Mozambicans and citizens of other aid-dependant African countries died as a result is not precisely known. Perhaps the governments in question should fund investigative research.
It's not as though there weren't instructive examples which should have caused reasonably well-informed activists to recognise that, in the Maoist formula, "error has been committed". Lapkin cites two.

When Sri Lanka banned DDT in the mid 1960s, malaria cases rose from 29 in 1964 to more than half a million five years later.
Ecuador, which expanded its use of DDT in the 1980s and 1990s, experienced a 60 per cent drop in infection rates.
Let us discount for bureaucrats with blithely Herodian intentions. How close to deliberate their grotesque implementation of zero population growth was will probably remain a mystery. What about the decent activists, let alone the self-respecting scientists with access to all the learned journals? How could slogans about saving the planet have engendered such a schizophrenic attitude towards the evidence? At what point did the realisation begin to dawn that the dominant paradigm was a big lie? Why is Greenpeace still active in India?
Lapkin sees these questions through the prism of a new form of First World vanity. "The anti-DDT crusade is made all the more outrageous by the distinct taint of neo-colonialism that is its indelible accompaniment. In a way, the push to ban this insecticide represents the ultimate in modern Eurocentric arrogance, the newest form of imperialism." He likens it to the "we know what's best" Kipling version of taking up the white man's burden imposing a green, insecticide-free colonial ideology of primal, untainted nature. Given the Herodian consequences, it seems to me that the more fitting analogy is with the Belgian than the British empire, and with Joseph Conrad's Mister Kurtz. Still there can be no doubting his conclusion that

"hubris, folly and ethnocentrism...spawned this unnecessary tragedy".
To that list must surely be added the Left's habitual response of taking for ever to recognise — and never admitting — when it gets things massively wrong. How massively? Crichton puts the price of environmentalist action at "somewhere between 10 and 30 million people since the 1970s". For those who dislike figures so rubbery, it should be noted that Third World population statistics pose all sorts of problems and that the interaction of malaria with other diseases and factors, such as poverty and malnutrition, complicates matters. Even the lowest estimate is a stupefying toll and one that reinforces the parallels with other monstrous, secular religions of the past century.
For Crichton, the most imperative of contemporary challenges is to retrieve responsible environmentalism from the clutches of those zealots for whom it has become a substitute faith and return to scientific discipline.

"I am thoroughly sick of politicised so-called facts that simply aren't true. It isn't that these 'facts' are exaggerations of an underlying truth. Nor is it that certain organisations are spinning their case... in the strongest way. Not at all — what more and more groups are doing is putting out lies, pure and simple. Falsehoods that they know to be false. This trend began with the DDT campaign and persists to this day."
Discovering the extent to which these strictures apply to the Australian Greens as a political party, and their allies, seems to me one of the most important challenges of contemporary journalism.

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