Fly spit may yet make its way into the medical mainstream. A new study on mice demonstrates that a vaccine based on a component of sand fly saliva can protect against leishmaniasis, an illness that infects hundreds of thousands of people each year.
Widespread in the tropics, the sometimes fatal illness produces disfiguring lesions. It's caused by a group of single-celled parasites that dwell inside tiny blood-sucking sand flies. When they pierce a person's skin, the flies inject the parasites into the bloodstream.