Dr Lim Thuang Seng, an immunologist appeals to the government to seriously reconsider their intention to release genetically modified mosquitoes in Pahang and Malacca. Dr Lim said this experiment will not lead to any solution in eliminating the aedes aegypti mosquitoes in Malaysia, but to put Malaysian in unnecessary potential health risks.

Dr Lim said although there was unofficial claim that experimental study on GM mosquitoes releases in Cayman island to eliminate aedes aegypti was a success, Dr Lim however, doubted how long the island will remain aedes aegypti free without continuous release of these male GM mosquitoes since the company that developed this GM mosquito claimed the male GM mosquitoes will die within a few days.

Dr Lim also described the experiences of Cayman Islands in combatting the dengue transmitting aedes aegypti mosquito. Cayman Islands, a British Overseas Territory in the Caribbean, started its mosquitoes elimination efforts way back in early 1950’s using the then still approved method of 5 percent DDT. Success was achieved and subsequence surveys confirmed the Grand Cayman Islands was free of aedes aegypti.  

In 1965 with the objective of promoting tourism, Cayman undertook another campaign to control the Grand Cayman Islands’ nuisance mosquitoes including the dengue transmitting aedes aegypti mosquitoes.

In 1966, the Mosquito Research and Control Unit (MRCU) established a network of ovipots and CO2 baited traps on the Grand Cayman Islands to detect and monitor the presence of aedes aegypti. No aedes aegypti were detected but subsequence surveys found presence of the mosquitoes in two other sister islands.

After the ban on the use of DDT, the Cayman Islands government used a 3-pronged strategy in controlling the mosquitoes population in the island that included: 

a) Prevention of entry through disinsection of ships and planes entering the island,

b) ovipot surveillance, and

c) chemical control.  

Successes were achieved despite reintroduction of the mosquitoes in 1973, 1980 and early 1990’s.

However, these re-emerged mosquitoes were subsequently eliminated.  Today, Cayman Islands continues to face the threat of dengue transmitting aedes aegypti mosquitoes with evidence of aedes albopictus becoming established in some cities where aedes aegypti was eliminated.

Dr Lim said, from the Cayman Islands experiences in combatting aedes mosquitoes, he believed the traditional methods of controlling mosquitoes used presently by the Health Ministry are effective enough if practised in combination and implemented persistently. 

Dr Lim explained that the Grand Cayman Islands with a land area of 200 sq km and surrounded by sea though effective in eliminating aedes aegypti, failed to prevent reintroduction of the mosquito from external sources. 

How can peninsula Malaysia with a much bigger land area and border with tropical Thailand in the north and Singapore in the south with close proximity Indonesia in the west, prevent the reintroduction of the mosquitoes?

Dr Lim further explained dengue fever is transmitted by aedes aegypti and aedes albopictus and the Cayman Islands’ experiences indicated when aedes aegypti is eliminated in one area, the possibility of the area being taken over by aedes albopictus cannot be ruled out even though albopictus is predominantly found in forest areas.

Dr Lim said genetic modification of mosquito genome has been going on for more than a decade, and it had raised concern from the scientific community as well as the public.

The issue we Malaysians face today is not about whether the male GM aegypti will mate in the wild and produces non-viable progeny, it is also not about how long the GM mosquitoes will survive in natural environment, but more about the existing unpredictable consequences of mutation of these GM mosquitoes which according to the company that developed it, suggested it requires the continuous release in enormously large number of these GM mosquitoes into our environment in order to be effective in eliminating the aegypti mosquitoes in Malaysia. 

Given our geographical and environmental setting as a tropical country with half a year of heavy rain fall, the GM mosquitoes’ mission is destined to fail.

Recent reports on the emergence of two new malaria-transmitting mosquitoes with similar physical but different genetically from the normal African anopheles gambiae also suggested the GM aedes aegypti may require genetic adjustment should similar mutation occur in aedes mosquitoes and that the abundant usage of tetracycline especially in animal farming industry may render the lethal tetracycline gene in GM mosquitoes ineffective faster than we thought.

It is not known what would happen when we release a large number of GM mosquitoes into the environment, whether all the GM mosquitoes will die as planned, or will a few manage to survive and multiply.

Are we absolutely certain that all larva or pupa will not develop into adult mosquitoes and will the GM mosquitoes or their lava or pupa not mutate? With all these uncertainties, can we trust the company that they can recapture all the GM mosquitoes that were released into the wilderness?

Dr Lim believes the potential danger to Malaysian of a natural aedes mosquito mutating to overcome a new insecticide is far less than the potential danger of a GM mosquito that has received additional DNA and mutated.

Finally Dr Lim hypothetically pointed out that assuming the GM mosquito is effective in eliminating all aegypti mosquitoes, dengue will continue to be transmitted but by aedes albopictus and in order to maintain the country aegypti free, continued release of GM mosquitoes is needed. In other word, the government will need to continue to spend a lot of money to keep the country free of aedes aegypti while cases of dengue continues to threaten the health of Malaysians