Download Lyme Disease Bacterium Came From Europe Before Ice Age

Lyme Disease Bacterium Came From Europe Before Ice Age
ScienceDaily (June 30, 2008) —
Researchers at the University of Bath have discovered that a bacterium that causes Lyme
disease originated in Europe, rather than in North America as previously thought.
The bacterium responsible for Lyme disease, Borrelia burgdorferi, originated in America, or
so researchers thought. Now, however, a team from the University of Bath has shown that
this bug in fact came from Europe, originating from before the Ice Age.
By understanding the origins of the bacterium and how it has evolved so far researchers
hope to be able to predict how it will continue to develop, and so find ways to prevent its
spread.
In the study, researchers from the University of Bath and colleagues from the UK and USA
studied the evolutionary history of the bacteria by looking at the sequences of eight so-called
'housekeeping genes', which evolve very slowly. They analysed 64 different samples taken
from infected humans and ticks in Europe and America.
In all, 33 different combinations of the housekeeping genes were found. The study's findings
appear to show that Borrelia burgdorferi originated in Europe but that the species has been
present in North America for a long time. The researchers suggest its re-emergence there in
the 1970s occurred after the geographic territory of the tick that carries the bacteria
expanded, for example through the restoration of woodland.
Lyme disease is a growing problem in Europe, Asia and - in particular - North America,
where it is now the most common vector-borne disease. The disease was named after Old
Lyme, Connecticut, the site of a number of cases in the 1970s. There is no vaccine for the
infection, which can cause arthritis and problems with the nervous system and heart if left
untreated.
References
Margos G et al. MLST of housekeeping genes captures geographic population structure and
suggests a European origin of Borrelia burgdorferi. Proc Natl Acad Sci U S A
2008;105(25):8730-8735
-------------------------------------------------------------------------------Adapted from materials provided by Wellcome Trust.