1.   The virus is transferred by mosquitoes.

2.   Mosquitoes then can transfer the virus to animals and humans.

3.   That lets the most resistant parasites survive, to be transferred by mosquito to the next victim.

4.   Host animals usually are birds, but mosquitoes can transfer the virus from birds to horses or other animals, including humans.

5.   If a mosquito transfers the virus to human blood, the bite can cause encephalitis, a swelling of the brain that is sometimes fatal.

6.   In their technique, a genetically engineered mosquito would transfer a protein through its saliva which would act as a vaccine to immunize a person against malaria.