Feared mosquito can be 'flying vaccinator'

Japanese researchers hope one day to turn blood-sucking mosquitoes - carriers of deadly malaria - into deliverers of a vaccine that could instead inoculate millions for free.

A new study shows real promise for turning the reviled insects into heroes by genetically modifying them to make them "flying vaccinators", according to scientists at Jichi Medical University north of Tokyo.

The researchers have already genetically modified a mosquito species so that its saliva contains a protein that acts as a vaccine against leishmaniasis, a sandfly-borne disease that triggers terrible skin sores and can be fatal.

The team confirmed that mice bitten by the transgenic mosquito developed an antibody to the disease, meaning they had built up immunity, said Shigeto Yoshida, the associate professor who has led the research.

Similarly the mosquitoes could be used to help combat malaria, perhaps a decade from now, said the malaria expert.

"What's good is that they don't charge you for vaccinations," Yoshida told AFP by telephone on Wednesday.

"You would be vaccinated without even noticing. You wouldn't need any drug and you wouldn't need to show up at a designated place for mass vaccinations."

Repeat bites would only strengthen the immunity, he said.

For now a problem is that no effective vaccine exists, because malaria's antigen, which triggers immune reactions, changes frequently.

However, Yoshida expects science will come up with a solution, and that the transgenic mosquito will ultimately help rid the developing world of a deadly scourge.

Nearly one million people die each year from malaria - most of them children - predominantly in Africa and Asia, according to the World Health Organization.

There are several anti-malarial drugs, none of them universally effective, and a treatment, called artemisinin.

"The treatment works but it is beyond the reach of people who need to worry about food for tomorrow. They just can't afford it," Yoshida said. "Malaria is a disease closely linked to poverty. A flying vaccinator matters a lot."

Yoshida conceded the new approach could raise ethical questions about carrying out vaccinations without informed consent.

"Technically speaking I believe it's a matter of 10 years or so, but it's a different issue whether society would accept it," he said.

Another problem is that the vaccinator mosquito may still pick up and spread the infected blood of a malaria-positive person.

Yoshida's team is hoping it can tackle this problem, by also developing a mosquito that kills malaria parasites inside its own body.

mis/fz/jit