Malaria-carrying mosquitoes rendered harmless after scientists use GM bacteria to kill off parasite in stomach

Malaria could be stopped by infecting mosquitoes with genetically engineered bacteria.

The modified bug destroys the parasite that causes the disease - meaning their bites will only be itchy, not deadly.

Known as Pantoea agglomerans, it was altered to secrete proteins poisonous to the malaria organism - but not harmful to mosquitoes or humans.

A study published in Proceedings of the National Academy of Sciences showed the new bacteria virtually wiped out the malaria parasite in the insects.

Professor Marcelo Jacobs-Lorena, of Johns Hopkins Bloomberg School of Public Health in Baltimore, Maryland, said: 'In the past we worked to genetically modify the mosquito to resist malaria, but genetic modification of bacteria is a simpler approach.

'The ultimate goal is to completely prevent the mosquito from spreading the malaria parasite to people.'

P agglomerans is found in the midguts of Anopheles gambiae, the most important malaria carrying mosquito species in Africa.

The engineered strain inhibited development of the deadliest human malaria parasite Plasmodium falciparum by up to 98 percent within the mosquito.

After the insects were infected with the bacteria by feeding them with cotton pads soaked in sugar the proportion carrying parasites decreased by up to 84 percent.

Prof Jacobs-Lorena said: 'We demonstrate the use of an engineered symbiotic bacterium to interfere with the development of P. falciparum in the mosquito.

'These findings provide the foundation for the use of genetically modified symbiotic bacteria as a powerful tool to combat malaria.'

Malaria is one of the most widespread and dangerous insect-transmitted human disease in the world.

It infects more than 500 million people - about one in twelve humans - and causes between one and two million deaths each year.

It is found in large areas of Central and South America, Africa and the Indian subcontinent. Singer Cheryl Cole fell seriously ill with the disease in 2010 after picking it up on holiday in Tanzania.

The incidence of malaria is increasing and new measures to combat it are desperately needed.