Genetically modified mosquitos: Boon or bane?

Posted on November 4, 2010. Filed under: Bio-diversity |

By G Vinod

COMMENT PETALING JAYA: Mosquitos, tiny in size and deadly in their bites, have been around for millions of years. And they continue to be a scourge in modern times.

One particular type, the female Aedes mosquitos, is still spreading death. One bite and it can cause the dengue fever which can turn fatal.

But now there is hope that the Aedes threat can be tackled through the aid of genetic science. Next month, about 4,000 to 6,000 genetically modified (GM) mosquitos will be released in Bentong, Pahang and Alor Gajah, Malacca, in a bid to reduce the Aedes population in those areas.

These male mosquitos are of the Aedes Aegypti strain.

The project is undertaken by the National Biosafety Board, which had initially planned to release the GM mosquitos in October but was postponed.

If everything worked out as planned, the GM male mosquitos will mate with the female strain, and the progeny will die before they can bite and transmit disease. This way, the Aedes population can be reduced, lessening the threat of a dengue outbreak.

The idea itself sounds admirable and noble in nature. Dengue fever kills millions of people across the globe every year and any effort to curb its spread should be supported by the public. However, before we launch a full-scale war on the mosquitos, we must ask this vital question: How much do we know of mosquitos?

For a start, mosquitos had been around for about 60 million years. The tiny insect, the size of a grape seed, had survived the Dinosaur Age, Ice Age, Stone Age, Industrial Age and is now thriving in the Information Age. It had lived through the destructive forces of nature and adapted itself effectively through all the climatic changes as well.

Distinct features

Mosquitos had wiped out legions of army before and killed great leaders of the past. Even Alexander the Great was suspected to have succumbed to malaria, a disease carried by the Anopheles mosquito.

Currently, there are more than 3,000 types of mosquitos living across the globe. Each type has its distinct features. Coming back to the Aedes, the female mosquito can lay about 100 eggs at one time. Once the eggs are hatched and the offspring turns into adult, the young male will be able to identify its mate within a distance of about one inch, based on the different style of wing beats both genders possess.

Once they have identified one another, both mosquitos will energise themselves by consuming nectar from the flower plants before mating. The female will then seek its first blood meal (human blood) in order to provide enough nutrients for its eggs. Later, it will lay its eggs and that is how a life cycle of an Aedes works.

Normally, a male Aedes lives for three days and the female for about a month. The latter can consume between three and six blood meals and lay eggs to about three times its lifespan.

Knowing that, let us pose a few questions on how effective the GM mosquitos are in reducing or wiping out the Aedes’ progeny.

How do we actually get the GM male to mate with the female? We know that both male and female recognise one another by the unique wing beats that only they possess. So if the GM mosquitos’ wing beats do not match with the Aedes’ natural “rhythm”, would the female mosquitos be “interested” to mate with the GM mosquitos?

Then there is the question of distance. As they only mate when they are about one inch apart, the entire project would fail if the GM mosquitos are released even one metre away from the females.

Assuming the GM strain and the female were successful in mating, Third World Network’s (TWN) senior researcher Lim Li Ching in August raised concerns that its progeny will only die in the absence of an antibiotic called tetracyline.

However, tetracyline is prevalent in Malaysia as it is used for medical, agricultural, veterinary and livestock purposes. Therefore, if the eggs are laid in an area exposed to this antibiotic, its progeny may live and we may end up having progeny of GM mosquitos running loose in the environment.

Survival skills

As it is, mosquitos are very skilful in adapting themselves. Hence, a GM mosquito’s progeny may have increased survival skills. In addition, mosquitos are known to be the link between several diseases (pathogen) and the human race.

With GM mosquitos running loose, it may bring another unknown disease to the human race due its newly acquired trait. It is not something new as the Japanese Encephlitis (JE), spread by mosquitos, was a relatively new disease in the medical world.

One expert claiming anonymity, asked: “Why are mosquitos not able to transmit the HIV virus despite the fact it can be be passed on by exchange of bodily fluid?”

“Do you know why? That is because it does not have one enzyme that will allow it to do so. Only one enzyme,” he said.

But a scary possibility exists: mosquitos, being highly adaptable, may mutate into a new strain complete with the missing enzyme which can make it an HIV carrier.

“When that happens, all hell will break loose,”said the expert. He fears that even if the government succeeded in wiping out Aedes, another strain will take its place and create a new health hazard.

Assuming the project does take place and the government decided to go nationwide with it, a lot of problems in terms of logistics and contigency plan needed to be settled.

For example, the male mosquito can only live for three days, making it “highly perishable goods”.

Who will monitor?

Oxitec, a biotech company based in Oxford, England, which is in charge of the Malaysian project, will need to produce billions or maybe trillions of these mosquitos for every district or even residential areas across the nation. Does it have the capacity to do so?

Oxitec needs to load and release the mosquitos within three days. Hence, a lot of work will have to be done: producing the mosquitos, packing them safely, and transporting and releasing them. And all these must be carried out according to strict healthcare guidelines. And somebody has to monitor it. Who is going to keep tabs?

Besides, if there are any flaws in the system or if something goes tragically wrong, who will be responsible? And what are the government’s contigency plans to handle any shortcomings or worse still, the real possibility of an outbreak of a new type of vector-borne disease? All these questions have yet to be answered.

Mosquitos are dangerous, bloodthirsty pests and we know very little about them. For instance, do we know where mosquitos hide during the day?

“The answer is, nobody knows. That is how much we know about mosquitos,” the expert said.

On the commercial side, it was made known that the project was mooted by Oxitec. But there is not much information on its Malaysian operations.

Who are its Malaysian partners? How much funding it is bringing in? Has it obtained approval of the Malaysian Pesticide Board? Has it obtained a patent for GM technology?

According to information on the website, Oxitec was established in 2002 and it applies technology developed at Oxford University. Its speciality is conducting research on controlling vector-borne diseases. The British company claimed that its GM mosquitos, which are programmed for early death, can control the spread of dengue fever.

But for now, “Project GM” is the baby of the National Biosafety Board. Oxitech is kept away from the prying eyes of the public.


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