This is scientific American 60 second science. I'm Christopher Intagiyata.

When Europeans arrived in the new world, they carried with them microscopic deadly organisms,

like smallpox, measles and flu, which caused devastating

outbreaks among the indigenous people.

One of those outbreaks was what became called the Cocholitzley epidemic of 1545, among the people known as the

Mischtex in what is today southern Mexico. The victims suffered rashes and

fevers, blood streamed from their eyes, noses, and mouths.

Millions died.

But we're still not sure what caused it.

So scientists looked to ten victims,

buried in communal graves in one of the afflicted towns for clues. They sequence DNA from within their pulpy tooth cavities.

Most studies of ancient bones ditch all the associated microbial DNA,

so that only the host DNA is analyzed.

But in this case, the bacterial and viral DNA

were the stars of the show,

which also meant a lot more genetic data to sift through.

The difference is the needle in the haystack.

Norenturos, a biochemist at Harvard University. The difference is the needle in the haystack.

Noreen to Ross, a biochemist at Harvard University.

This is a much bigger haystack.

Using a new algorithm to help him dive into that huge haystack, they found a needle.

Genetic evidence of the deadly salmonella enterica

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