Sterilising mosquitoes by radiology could halt spread of dengue fever

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As dengue fever remains a deadly threat to lives with increasing number of patients, the Thai Institute of Nuclear Technology has proposed radiology process to sterilise Aedes mosquito, the main carrier of the dengue virus, in the effort to reduce the spread of the carriers.

According to health officials, this year saw a dramatic increase of the number of Thai people being afflicted with dengue fever.

They said this was the result of the exponential increase of the number of Aedes mosquito population in the country.

The rising concern forced health officials to consider ways to reduce their number.

The Thai National Institute of Nuclear Technology has proposed employing radiology as a means of sterilizing mosquitoes which they say will result in a dramatic reduction in their numbers.

The experiment was conducted in Nakhon Nayok office of the Institute.

Nuclear technology scientists here said the first step in the process is to bring in Aedes mosquitoes that are free of dengue virus and breed them in sealed containers. These will be kept until they reach larvae stage and finally growing to pupa or worm stage.

At this stage, scientists will then separate the males from the females which will then be irradiated.

Upon reaching pupa stage, scientists are now able to differentiate between the sexes as the males have a significantly smaller head than the females.

The males will then be separated and put into containers which will be irradiated with 70 Gy (Gray) of Gamma rays for a little over a minute from Cobalt 60 radiology machines which will render them sterile.

The process poses no danger to human or pet animals as the intensity is comparable to radio-waves and micro-waves that we encounter on a daily basis

One of the scientists Wanich Limh-Ophasommanee said they have discovered that the amount of radiation that these mosquitoes are exposed to will render them 100% sterile.

Other than that, they are not in any way physically harmed. They are still healthy males that are able to compete in the wild with other males to breed.

The scientist said  that the irradiated mosquitoes will be kept until they reach maturity before being released. Tests have shown that females that have been fertilized by these male mosquitoes produce eggs that do not hatch.

“When these sterilized males are released into the wild and breed with females, the eggs will not have been fertilized and will fail to hatch. This in turn will directly result in a dramatic reduction of the next generation of Aedes mosquitoes,” he said.

As we continue to release more of them, each subsequent generation will see their numbers reduced even further. We may even see a complete eradication of the species in some certain areas.

He said first trials to release the sterilized mosquitoes will be carried out soon to see if these males can compete with normal male Aedes mosquitoes to breed in the wild.

The success ratio can then be determined so that the correct numbers to be released in a particular area can be specified. The scientists say that the trials should be completed within 2 – 3 months.

These sterilized mosquitoes will be released into critical areas in the country to help curb the spread of dengue fever and other mosquito related diseases, he added.