Modified mosquitoes may halt spread of malaria

Mosquitoes infected with a strain of bacteria may be used to halt the spread of malaria as they show signs of resistance to the parasite, a new study has found.
The study conducted at Michigan State University shows that the transmission of malaria via mosquitoes to humans can be interrupted by using a strain of the bacteria Wolbachia in the insects.
Wolbachia would act as a vaccine of sorts for mosquitoes that would protect them from malaria parasites, researchers said.
Treating mosquitoes would prevent them from transmitting malaria to humans.
"Wolbachia-based malaria control strategy has been discussed for the last two decades," said Zhiyong Xi, MSU assistant professor of microbiology and molecular genetics.

"Our work is the first to demonstrate Wolbachia can be stably established in a key malaria vector, the mosquito species Anopheles stephensi, which opens the door to use Wolbachia for malaria control," said Xi.

Xi's team successfully demonstrated how Wolbachia can be carried by this malaria mosquito vector and how the insects can spread the bacteria throughout the entire mosquito population.
Researchers showed that the bacteria can prevent those mosquitoes from transmitting malaria parasites to humans.
"We developed the mosquito line carrying a stable Wolbachia infection. We then seeded them into uninfected populations and repeatedly produced a population of predominantly Wolbachia-infected mosquitoes," Xi said.

The key to the malaria research was identifying the correct species of Wolbachia - wAlbB - and then injecting it into mosquito embryos. Out of the thousands of embryos injected by research associate Guowu Bian, one developed into a female that carried Wolbachia.
The mosquito line derived from this female has maintained Wolbachia wAlbB infection with a 100 per cent infection frequency through 34 generations. The number could grow higher as this is simply the last generation the researchers have bred thus far, Xi said.
The team then introduced various ratios of Wolbachia-infected females into a noninfected mosquito population. In each case, the entire population carried the bacteria in eight generations or less.

The study was published in the journal Science.