"Magic potion"

Scientists have found proteins in the black fly’s saliva that help spread parasites that cause a devastating eye disease.

Researchers are reporting the first identification of a "magic potion" of proteins in the saliva of the black fly that help this blood-sucking pest spread parasites that cause "river blindness," a devastating eye-disease.

A better understanding of these proteins may lead to better drugs and a vaccine for river blindness and other diseases spread by biting insects. Also known as onchocerciasis, river blindness affects more than 17 million people worldwide, particularly in rural Africa. 

In the new study, José M.C. Ribeiro and colleagues explain that the saliva of adult female black flies contains substances that mute the human body's natural defenses. This chemical cocktail makes the body more vulnerable to disease when infected flies bite into the skin. Until now, however, nobody had identified the specific chemicals involved in this devious action.

The scientists collected salivary glands from hundreds of adult female black flies and isolated the proteins using high-tech analytical gear. They identified 72 different proteins, including several new to science. These proteins could serve as the basis for developing drugs or vaccines against diseases transmitted by the black fly and other blood-sucking insects, including mosquitoes, midges, and sand flies, the researchers say.