Most people view mosquitoes as dirty, harmful disease carriers. But these blood-sucking bugs might hold the key to keeping third-world residents safe from a deadly disease.

Scientists in Europe recently conducted an experiment using mosquitoes to help patients develop immunity to malaria, which kills nearly a million people every year. The results are especially encouraging because some studies have shown that the drugs used to treat malaria are becoming less and less effective.

For the experiment, the scientists divided participants into two groups. Ten volunteers were assigned to the immunity group, while another five were in a control group. All were given a powerful drug designed to treat malaria for about three months, and were exposed about once a month to mosquitoes. Those in the immunity group were exposed to mosquitoes infected with malaria, while those in the control group were not.

Next, all fifteen stopped taking the malaria drug and were bitten by malaria-infected mosquitoes. Scientists called the results astounding: None of the ten volunteers in the control group developed parasites in their bloodstream while all five in the control group did.

Scientists say this approach would be difficult… if not impossible… to administer to a large group of people. But it signals a shift from developing a vaccine in a laboratory to attempting to protect people by using the whole parasite. In fact, a Maryland-based company is already working to create a safe version of the parasite that could help people build immunity to malaria.

Mosquitoes as symbols of health and wellness? It just may happen someday.