Issue 28 / 23 July 2012

HOW selective we can sometimes be about science, particularly when our most cherished beliefs are at stake.

When it comes to climate change, environmental groups generally treat scientists as heroes, relying on the consensus of experts to bolster their campaigns.

Raise the topic of genetic engineering, though, and a very different attitude emerges in some environmental circles. Suddenly, researchers morph into power-mad Dr Frankensteins intent on visiting their monstrous offspring on an unsuspecting world.

Take dengue fever and the mosquito Aedes aegypti that carries it.

Dengue fever is one of the fastest growing viral infections in the world. The WHO estimates 2.5 billion people are now at risk of contracting the potentially lethal illness. About half a million are hospitalised with severe dengue each year and about 20 000 people die.

With no vaccine and no specific treatments, our only weapon against dengue is control of its vector, the white-banded A. aegypti mosquito.

Until now, that has generally meant habitat reduction and widespread use of insecticides in affected areas, including in north-eastern Queensland where the disease is regularly imported by travellers and returning residents.

New technologies are opening up the possibility of more effective control — perhaps even elimination — of this disease-carrying insect, but not everybody welcomes such developments.

When a UK biotech company proposed releasing transgenic mosquitoes in the US Florida Keys region — males modified so that their offspring would not survive to adulthood — it caused uproar locally and in key environmental groups such as Friends of the Earth.

Scientists who presented their proposal at one public meeting were accused of playing God and their creations described as “robo-Franken mosquitoes”, according to an article in The New Yorker.

“It breaks my heart that you guys have the nerve to come here and do this to our community”, one woman said. “Anything genetically modified should not be touched.”

A Florida businesswoman who has collected 100 000 signatures on a petition opposing release of the mosquitoes told Nature local people were confused about the issue: “I started thinking, ‘Oh my goodness, what if these mosquitoes bite my boys or my dogs? What will they do to the ecosystem?’.”

Fear is an understandable response to new technologies, especially when these are poorly understood and contain scary words like “genetic engineering”. And individuals and lobby groups do of course have every right to hold scientists and commercial interests to account, demanding rigorous examination of the potential risks of any new development.

In the case of A. aegypti, those risks do appear low. Male mosquitoes do not bite humans or other animals so would not transmit the altered genetic material, even if that was technically feasible, and the mosquitoes are not native to the US (or Australia) so disruption of the ecosystem in those countries seems unlikely.

Of course, that doesn’t mean we should be complacent about potential risks. Scientific hubris has certainly created unexpected, and sometimes catastrophic, consequences in the past — think cane toads or mad cow disease.

But in the face of new technologies such as genetic engineering, we need a better standard of debate, one that is based on science rather than fear.

Yes, we need to examine risks, but we need to weigh them against potential benefits for public health.

In the case of dengue fever, it’s worth remembering that current strategies rely on large-scale insecticide use in heavily populated areas — hardly a risk-free approach.

There’s no doubt our enquiring minds get us into trouble sometimes, but they have also brought us myriad advantages, from antibiotics to organ transplants.

We need to learn from the mistakes of the past, to be scrupulous in examining risks, to put in place proper regulatory frameworks.

But if our society wants to keep finding new ways to relieve suffering, we also need to avoid being paralysed by fear.

Jane McCredie is a Sydney-based science and medicine writer.

Posted 23 July 2012

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