Monday, May 13, 2013

Making Mosquitoes Malaria Free

Advances in Medicine

Stopping the Transmission“The mosquito Anopheles stephensi is a conduit for
malaria infection 
in humans in the Middle East and South Asia,” says Nature News. Malaria
begins when an infected female Anopheles mosquito bites a human, which then introduces the
protists—a type of microorganism of the genus Plasmodium—into the circulatory system. The
protists then travels to the liver where it matures and reproduces
Photo Credit: CDC 
Source: Nature News

An article, by Beth Mole, in Nature News says that scientists have come up with a novel approach to combat malaria infected mosquitoes: introduce a bacterium that makes mosquitoes resistance to getting malaria in the first place, so they cannot transmit it to humans. It sounds so simple, and yet initial lab trials show much promise.

Mole writes:

A team led by Zhiyong Xi, a medical entomologist at Michigan State University in East Lansing, infected Anopheles stephensi mosquitoes with Wolbachia bacteria to produce insects that could pass the infection on to their offspring. Female mosquitoes that carried Wolbachia also bred with uninfected mates, the researchers report today in Science, swiftly spreading the malaria-blocking bacterium to entire insect populations within eight generations1.
“This is the first paper reporting that it is indeed possible to use Wolbachia to control malaria,” says geneticist Steven Sinkins of the University of Oxford, UK. But he cautions that field trials will be the real test of this advance.
Wolbachia has already been used to block mosquitoes’ ability to transmit other human pathogens. For instance, scientists have created heritable infections in Aedes aegypti mosquitoes that stop the insects from transmitting dengue virus2. But manipulating those mosquitoes that carry the malaria parasite exclusively—from the genus Anopheles—has proved trickier.

Researchers are not sure how Wolbachia manages to boot out other pathogens, but they suspect that the bacteria create toxic environments within the mosquito, possibly by activating the insect’s immune response. Indeed, Xi and his team found that the tissues of their infected mosquitoes contained more reactive oxygen species—which inhibit pathogens such as P. falciparum—than insects that were uninfected with Wolbachia.
Such are initial lab results; now the researchers will have to test their findings in a real-life environment. Malaria is a disease that affects hundreds of millions of individuals. Wikipedia says: “The World Health Organization has estimated that in 2010, there were 219 million documented cases of malaria. That year, between 660,000 and 1.2 million people died from the disease,[1] many of whom were children in Africa.” 
Any medical and scientific breakthrough is a good thing; let's hope that this initial finding by Zhiyong Xi, at Michigan State, proves successful in field trials.
You can read the rest of the article in [NatureNews]