India is the worst in terms of dengue cases: Oxitec’s Kevin Gorman

Gorman, senior field operations manager at Oxitec, speaks about how genetically modified mosquitoes fight dengue


Photo: Bloomberg
Photo: Bloomberg

Oxitec Ltd, a UK-based biotechnology firm, has been working with India’s privately held health and agriculture firm GBIT since 2011 on a UK-India funded project, ‘Sustainable Dengue Prevention’, under the India-UK Collaborative Industrial Research and Development Programme.

The biotechnology evaluated by these two companies now awaits the approval of the genetic engineering approval committee (GEAC) under the ministry of environment, forest and climate change.

Kevin Gorman, senior field operations manager at Oxitec, who is a specialist in insect pest management and PhD in insecticide resistance management, spoke from Oxford, UK, in a telephone interview about how genetically modified mosquitoes fight dengue. Edited excerpts:

When are you expecting to get approval for commercializing this technology in India?

We don’t know when they are likely to give approval. There is no timeline. We have just applied. I have no idea of when it might be approved or whether it will be approved. Of course, the positive support from the Indian and UK governments is on the strong side. But this is a bio-safety decision and rests solely with the GEAC.

We have released now well over 90 million mosquitoes worldwide and there has never even been one single adverse event either with humans or with environment. We have been studying this particular strain for about 150 generations in the laboratory, so it is quite a long approach.

How is the mosquito infestation in India compared to the rest of the world?

It is probably the worst in the world in terms of dengue cases. This mosquito (Aedes aegypti) is by far the most prevalent in India.

Will your technology work? And if it does, to what extent could it really reduce dengue cases?

There are a number of reasons why the situation is getting worse and one is that insects are becoming resistant to chemicals. But also, the species is very invasive. Our technology can get the (mosquito) population down to below dengue transmission threshold as predicted by (computer) models. So we are quite confident that we can prevent dengue epidemics. In our case we have seen over 90% reductions.

Do you think India might have reservations about releasing GM mosquitoes?

Across the world, GM organisms are being increasingly registered. Quite rightly, people are evaluating the technologies very carefully. Every one of these technologies is different. So GM foods, for example, have different properties. This particular technology—genetically modified insects—are different from other GM insects but they are extremely safe, they don’t persist in the environment because they are actually destined to die. They carry a self-limiting gene. It is a very clean technology but it still requires careful assessment.

How expensive could it be and who could buy it?

In terms of what scale it would be, depends on the resources available to the customer and the customer would likely be the municipality, governments and state governments and public health pest controllers.

What about the cost?

The cost is very difficult to predict because we are still in learning stages and the technology is developing, but also, the production costs are coming down all the time because we are getting better. Once you have got control of the (mosquito) population, there are all sorts of options to exercise—people can stop releasing (GM mosquitoes); wait to monitor it till it comes back; keep releasing to make sure they stay away; or they can release them in hot spots of risky areas. So there are all sorts of different strategies. But we expect that the cost would be similar or less than existing technologies.

The funding that has been conditionally approved (£340,000) comes jointly from the Indian and UK governments to roll (out) the projects in two villages simultaneously. It is a specific evaluation project to look at the control in two villages simultaneously, which will be somewhere in the region of 5,000 people. It is a two-year project. It has not started yet, and releases won’t take place until we have regulatory approval.

What is the colour of the GM mosquito?

When you look at it in green light, you see a fluorescent red.

How do you introduce the two genes in the mosquitoes?

One is just a protein production gene and that is the one that makes them die. All that happens is that the insect overproduces its protein and that interrupts the cell function. So there is no toxin—it is just over production of protein.

The second gene is the fluorescent one—it is the marker gene and that allows us to track and trace these insects.

So this is an injection technique. In fertilized mosquito eggs, we inject this trans-gene in the form of DNA. And that gets integrated into the existing DNA of the eggs and you get an insect that houses those two extra genes.

It’s worth noting that we do not need to keep injecting the mosquito eggs because there is a more efficient way to produce more of our mosquitoes: the genes were originally injected into mosquito eggs in 2002 to create the strain, OX513A, and we just keep the strain going by giving them an antidote in the production facility so that they can reproduce.

Are mosquitoes really mutating, the wild mosquitoes as well as those that are exposed to repellents and pesticides?

Every organism mutates genetically. Everything has a mutation rate. It is just a natural thing (that happens when they reproduce). The wild population of mosquitoes are becoming increasingly resistant to pesticides. That is due to mutation. Their genetic mutation allows them to survive.

Is it happening at a faster rate in India?

Mosquitoes around the world are becoming more and more resistant to insecticides due to genetic mutation. India is the same as anywhere else. The more insecticides you use, the more resistance you get.

Is there a way to track the rate of mutation?

Insecticide resistance happens in different rates depending on how much you use it. But typically insecticide resistance can develop after a few years of use (of chemicals). So it could be anything—3, 4, 5, 6 or 10 years of use maybe before resistance develops. Insecticides have been used extensively so resistance has been quite widespread in this species. Even brand-new insecticides have a limited life.

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