Dr Pattamaporn and her British post-doctoral trainee.

With a tiny glass syringe in his hand, British academic Robert Butcher gradually injects the Wolbachia bacteria into a female Asian tiger mosquito as it lies anaesthetised on the microscope after being fumigated with carbon dioxide.

Pattamaporn supervises beside him.

"About half of the mosquitoes die during handling," Butcher says.

If successful, after returning to consciousness, the mosquito will produce offspring carrying the Wolbachia bacteria in the cytoplasm of their egg cell.

This bacteria should kill its host when it is just seven-days old.

The bacteria is natural and many benign strains are found in insects, however, the so-called "pop corn strain" can halve the host's life.

The micro injecting of the Wolbachia bacteria is a crucial part of an international project funded by Bill and Melinda Gates Foundation's Grand Challenges in Global Health (GCGH) initiative. The other parts of the project are being conducted in Australia, to sequence the genome of the bacteria, and Japan, to search for further uses for the bacteria.

The project is one of 43 health research projects, selected out of 1,600, which won GCGH funding last year.

Pattamaporn's team is the only Thai team joining the US$400 million (Bt15.3 billion) GCGH project. Her project will receive US$7 million over five years. Besides Butcher, a Guatemalan academic has joined the project.

Normally, mosquitoes live about a month. When they are around 14-days old they are ready to inject the dengue virus after biting an infected human, incubating the disease in their gut and allowing it to reach the salivary glands.

"The Wolbachia bacteria would make the mosquito die before it can transmit dengue virus," she says.

Pattamaporn, who has studied the Wolbachia bacteria since 1994 after returning from her World Health Organisation-funded training at Yale University, says to allow the bacteria to become infected into generations of mosquitoes, it must be injected into eggs.

That way, all female offspring will carry the bacteria in their cytoplasm and pass it to their offspring.

As female mosquitoes will still live long enough to feed on human blood and lay a set of eggs before they die, there will be little evolutionary pressure on them to resist the bacteria, Pattamaporn said.

"As part of an ecosystem, the mosquito has its role in food chain. If we eradicated them it might have adverse impacts," she added.

The scientist believes that to shorten the life of the dengue mosquito is the best way to control the disease, listed by the WHO as endangering two-fifth of the world's population. Mosquito sprays are never fully effective and vaccinations must vary to tackle different types of the virus, she added.

There are now four types of dengue virus and the severity varies with each case.

Pattamaporn insists her project is not genetic engineering.

"We just let the female mosquito carry the bacteria in its cytoplasm and have nothing to do with its cells or genetics."

The team has now succeeded in producing a third generation of mosquitoes with the bacteria in its cytoplasm. All of the mosquitoes are cared for in her Mahidol University lab.

She says more mosquitoes with the bacteria must be produced and a DNA copy has to be made to make sure that the bacteria is stable in the mosquitoes in every generation before success can be claimed.

"It's still early," she says.

According to Pattamaporn, scientists in UK and US are now trying to use the same technique to shorten the lives of malarial mosquitoes but without success.

If the team is successful, millions of mosquitoes will be bred and released and although they will probably still enjoy a meal on human flesh, they should be incapable of spreading the dreaded dengue.

Pennapa Hongthong

The Nation