MILLIONS of genetically modified (GM) male "warrior" Aedes mosquitoes will soon be released into the fishing village of Pulau Ketam off Selangor as part of international field trials to fight the dengue scourge. The Aedes mosquito is the main vector for dengue and chikungunya fever. Much has to be seen but we are optimistic since if it succeeded, it is going to be major breakthrough in our war against dengue.
It is said that the conventional sterilisation programmes using radiation or chemical treatment to foster sterility, which were tried on mosquitoes as well, did not work. Irradiation rendered these mosquitoes so sickly and unattractive (not so handsome ma ) that their female counterparts shunned them for the wild ones. Conventional methods such as fogging have been ineffective in controlling the spread of these diseases.
If this field trials prove successful, the next step would be to introduce the killer mosquitoes in bigger towns which have a high incidence of dengue. The hot spot map would locate the dengue prone areas.
The location on the island for the field experiment has to be selected carefully since the settlement is unique. A lot of travelling to and fro are taking place daily between the island and the the mainland. Some of these "warriors" may hitch a ride to the mainland and interact with a more diversified fauna on the mainland. What would happen if the "genes" found its way into other species of animals? Another story from science fiction film? no, this time is going to be real. Back home at your doorstep.
Please read on.
2008/04/28
Big hope for 'warrior' Aedes
By : Heidi Foo|
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KLANG: The Health Ministry will consider all factors when conducting field trials using genetically modified (GM) Aedes mosquitoes.
"It is a technological breakthrough and we are hoping that it can control the disease," he said, adding that research was also being done on vaccines.
Liow was commenting on fears expressed by environmentalists that the release of GM Aedes mosquitoes could cause more harm than good.
The New Sunday Times reported yesterday that the Institute of Medical Research and a company partly owned by the University of Oxford would release "warrior" mosquitoes in Pulau Ketam off Selangor to combat the dengue scourge.
He said those who returned could apply for research grants from the government.
He said the eight Taiwanese universities that were recognised by the government were Medical School of Taiwan, Defence Medical School, Yang Ming Medical School, Chung Kung Medical School, Taipei Medical School, China Medical School, Chung Shan Medical School and Kaoshiung Medical University.
NST Online
2008/04/27
'Warrior' mosquitoes to fight dengue scourge
By : P. SELVARANI|
If the Pulau Ketam field tests are successful, the days of the Aedes mosquito may be at an end. |
The days of the Aedes mosquitoes appear to be numbered, thanks to the efforts of a British bio-tech company and Malaysia's Institute of Medical Research, writes P. SELVARANI.
The GM male Aedes aegypti mosquitoes, which carry killer genes, will be released into the wild to eliminate the Aedes mosquito population which spreads dengue fever.
The field trials will be undertaken by the Health Ministry's Institute of Medical Research (IMR) in collaboration with British-based Oxitec Ltd, an insect bio-tech company part-owned by the University of Oxford.
This follows the success of confined lab trials which were conducted under the supervision of the IMR over the past year.
The team is undertaking a baseline survey of the island, which is reported to have a high number of the Aedes aegypti mosquitoes.
Oxitec has advertised on its website vacancies for the Pulau Ketam field-testing job, which includes a position for a senior entomologist.
The field trials on the island, which is a 30-minute boat ride from Port Klang, are expected to be carried out over a year.
Health Ministry and IMR officials did not want to comment on the tests.
In February, Oxitec had announced that it planned to release the GM mosquitoes in Malaysia on a large scale in three years, following its successful trials.
Calcutta's The Telegraph newspaper had quoted Oxitec's head of public health, Seshadri S. Vasan, as saying that the first confined field study under the supervision of the IMR "yielded encouraging results".
Sources said the controlled lab tests done here were the first in the world and was a breakthrough in the fight against dengue, which has grown to alarming proportions across the globe in recent years.
The technique involves releasing GM male Aedes mosquitoes to mate with the female Aedes mosquito. The lethal genes cause the larvae to die.
(Only a female mosquito can transmit the disease-causing germ because it, and not the male mosquito, has a proboscis that is capable of piercing the human skin.)
The Aedes mosquito is the main vector for dengue and chikungunya fever and conventional methods such as fogging have been ineffective in controlling the spread of these diseases.
However, environmental non-governmental organisations fear that releasing these GM mosquitoes in the wild may affect the ecosystem and cause further damage.
Gurmit Singh, the chairman of the Centre for Environment, Technology and Development, said: "Like all GM organisms, once they have been released in the wild, how do you prevent them from interacting with other insects and producing mutants which may be worse than the Aedes mos-quito?"
It is learnt that if the Pulau Ketam field trials prove successful, the next step would be to introduce the killer mosquitoes in bigger towns which have a high incidence of dengue.
The Telegraph had also reported that the sterile insect technique (SIT), which involves releasing millions of sterile male insects over a wide area to mate with the native female ones, had been around for decades.
It said the conventional sterilisation programmes using radiation or chemical treatment to foster sterility, which were tried on mosquitoes as well, did not work.
Irradiation rendered these mosquitoes so sickly and unattractive that their female counterparts shunned them for the wild ones.
On the other hand, mosquitoes subjected to Oxitec's proprietary technique, called RIDL-SIT, remained healthy and attractive enough to woo the native female insects.
This was proved in independent case studies in Oxford and France and in contained semi-field trials in Malaysia.
Vasan was quoted as saying that the latest study in Malaysia showed that "up to 50 per cent of the wild type female mosquitoes chose to mate with Oxitec's RIDL male mosquitoes".
The paper added that Oxitec had received regulatory and import permits for confined evaluation in the US, France and Malaysia
Maps predict places at greatest risk of dengue
WHAT THE SATELLITES SEE IN SUBANG JAYA (pdf) |
IMAGINE opening a map and immediately being able to identify the area where a dengue outbreak is going to occur.
| Darus Ahmad is working to increase the accuracy of the risk maps |
Now imagine doing this monthly and preventing an outbreak.
This would be the reality next year if Malaysian Remote Sensing Agency director-general Darus Ahmad has his w ay.
Preferring to focus on prevention rather than the cure, Darus came up with the idea of using remote sensing technology to come up with a dengue risk map.
“The idea came about when we realised that current approaches are only used to address the issue after it had already happened.
“So we thought of preventing it before it happened by narrowing down the likely areas to be affected before the dengue outbreak even occur red,” Darus said.
The map, which is expected to be ready by the end of the year, would identify dengue “hot-spots” on a monthly bas i s.
The map will also be able to identify areas which are not dengue-prone in the past but may be in the future.
It will also show the exact locations and the severity of dengue outbreaks.
In addition, the map will also be able to identify activities which contribute to the presence of Aedes mosquitoes.
“For example, we found that the number of dengue cases was lower in areas with bungalow houses than those with terrace houses,” Darus said.
The dengue risk map pilot project started in 2005 and covered the area of Subang Jaya .
It was jointly conducted by the Malaysian Remote Sensing Agency, Institute for Medical Research and the Subang Jaya Municipal Council.
Subang Jaya was chosen for the pilot project because it was among the areas with the highest number of dengue c a s e s.
The pilot project involved drawing up dengue risk maps for the years 2002 and 2005.
To test the veracity of the maps, they were compared with the incidence of dengue outbreaks in those two years.
As the maps proved to be accurate, it was decided a risk map for 2009 would be drawn up.
The 2009 dengue risk map identified Seri Kembangan and USJ11 as areas with the most severe probable incidence of dengue.
It also found that 20 per cent of the 437,121 square kilometres area studied was in the “very high risk” category for dengue outbreaks.
“Some of the areas in this category have no dengue cases at the moment but have a high probability of having dengue outbreaks in the future.
“We use satellites to monitor physical parameters or factors that affect the population of Aedes mosquitoes.
“This is then related to weather factors and ground data provided by the Health Ministry.We then map out the potential dengue risk areas.” The satellites are used to measure land use changes and its patterns, types of housing, land surface temperatures, land surface elevation and population density.
Weather patterns would also be included as one of the measurements in the future, said Darus.
“I hope the dengue risk map will help lead to better prevention methods.” Once the pilot project map is ready, he plans to roll it out nationwide and make the map available to the public.
“If the public are aware of the high-risk areas, they will most likely be more co-operative and more responsive to government advice.” Darus said the process of coming up with the risk map had also resulted in some interesting findings.
“We found that most dengue cases happened near construction sites and industrial areas. Interestingly, the areas with the highest number of dengue cases have mostly terrace houses.
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