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Add syphilis to Columbus' discoveries, study says
He and his crew likely brought the bacterium out of the New World, leading
to its global spread, a genetic analysis finds. That conclusion is hotly
debated, however.

By Jia-Rui Chong
Los Angeles Times Staff Writer

January 15, 2008

The spread of syphilis across the globe was probably sparked by Christopher
Columbus and his crew, who ferried the bacterium, or a version of it, from
the New World to the Old World, according to a new genetic analysis
published Monday.

A comparison of 23 strains of Treponema pallidum bacteriumfound that the
modern variety that causes the sexually transmitted disease was most
closely related to bacteria collected from a remote tribe in Guyana.

Because the tribe has had little contact with the outside world,
researchers think the strain is very close to what was circulating in the
Americas at the time of Columbus' voyage in 1492.

The study, published in the journal Public Library of Science Neglected
Tropical Diseases, adds more fuel to the long debate over the origin of
syphilis.

"There are loose ends, but . . . it looks as if it's very interesting
evidence pointing to New World treponematosis being the ancestor of
venereal syphilis," said Della Collins Cook, a physical anthropologist at
Indiana University in Bloomington who was not involved in the study.

But other experts argued that the study's findings were still not strong
enough to overturn a theory that venereal syphilis in Europe evolved from
local strains.

A commentary by molecular anthropologist Connie J. Mulligan of the
University of Florida and others, published in the same journal, also
criticized the study, saying the genetic analysis was too murky to create a
clear lineage of the disease.

"I think the jury is still out," she said.

The venereal form of syphilis is caused by a subspecies of Treponema
pallidum.

Other subspecies cause yaws, a tropical disease, and bejel, an illness
found in hot, dry climates. Neither of the diseases is usually sexually
transmitted.

In the new study, researchers sequenced yaws, bejel and syphilis strains
from around the world.

Kristin Harper, an evolutionary biology graduate student at Emory
University in Atlanta and lead author of the study, said the team compared
the sequences to rabbit syphilis, from which the human variety originally
branched off.

The genetic analysis showed that bacteria collected from yaws patients in
Guyana were closest to the rabbit strains, although the samples from Guyana
were incomplete because they degraded from the tropical heat on the trip
back.

Still, the incomplete results agreed with historical documents, which show
the first recorded outbreak of venereal syphilis occurred about 1495 when
the armies of King Charles VIII of France invaded Naples.

The later disbanding of the army helped spread the disease across Europe.

But Simon Mays, a human skeletal biologist at English Heritage, an advisory
body to the British government on historical preservation, noted that other
evidence argued that syphilis existed in the Old World long before
Columbus.

For example, scientists found evidence of venereal syphilis in the teeth of
a skeleton from 13th century Turkey.

The new study "dismisses this evidence much too easily," Mays said.

Harper acknowledged that the genetic analysis was limited because they
didn't have more of the Guyana strains.

She added the analysis also could not tell if the bacterium Columbus took
back was actually venereal syphilis or an organism that developed the
ability to transmit sexually as it circulated in Europe.

"We decided to present this evidence because it is very suggestive," she
said.

"The controversy is not going to stop here."

jia-rui.chong@...