This is a scientific American 60 second science.

I'm Cynthia Graber.

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Leishmaniasis is a sometimes fatal disease marked by skin ulcers, fever, and

spleen and liver problems.

It currently affects about 12 million people, mostly in the developing world,

with about 2 million new infections annually.

It's caused by a parasite which is spread by sandflies.

There's not yet a good vaccine against

leishmaniasis, but researchers have shown that it may be worthwhile to target not

the parasite but its fly host. They report good results in non-human primates in the journal Science Translational Medicine.

Vaccines usually trigger our immune systems to rally against a pathogenic agent.

If that agent should actually show up, the immune system can disarm it.

But in this case, scientists aimed at the carrier, the sandfly.

When an infected fly bites a victim, it injects parasites

and its own saliva.

So the researchers subjected monkeys to repeated bites from

uninfected sandflies, then to bites from infected sandflies, and the monkeys

bitten first by the uninfected flies were partially protected when

confronted with the Lishmaniasis parasite.

Seems that exposure to fly saliva alone could elicit an immune response.

The researchers then determined that one particular protein in the sandfly

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