Amber discovery indicates Lyme disease
is older than human race
 |
| Trapped in amber, tick carrying spirochetes [Oregon State University] |
Lyme
disease is a stealthy, often misdiagnosed disease that was only recognized
about 40 years ago, but new discoveries of ticks fossilized in amber show that
the bacteria which cause it may have been lurking around for 15 million years
-- long before any humans walked on Earth.
The
findings were made by researchers from Oregon State University, who studied
15-20 million-year-old amber from the Dominican Republic that offer the oldest
fossil evidence ever found of Borrelia, a type of spirochete-like
bacteria that to this day causes Lyme disease. They were published in the
journal Historical Biology.
In
a related study, published in Cretaceous Research, OSU scientists
announced the first fossil record of Rickettsial-like cells, a bacteria
that can cause various types of spotted fever. Those fossils from Myanmar were
found in ticks about 100 million years old.
As
summer arrives and millions of people head for the outdoors, it's worth
considering that these tick-borne diseases may be far more common than has been
historically appreciated, and they've been around for a long, long time.
"In
the United States, Europe and Asia, ticks are a more important insect vector of
disease than mosquitos," Poinar said. "They can carry bacteria that
cause a wide range of diseases, affect many different animal species, and often
are not even understood or recognized by doctors.
"It's
likely that many ailments in human history for which doctors had no explanation
have been caused by tick-borne disease."
Lyme
disease is a perfect example. It can cause problems with joints, the heart and
central nervous system, but researchers didn't even know it existed until 1975.
If recognized early and treated with antibiotics, it can be cured. But it's
often mistaken for other health conditions. And surging deer populations in
many areas are causing a rapid increase in Lyme disease -- the confirmed and
probable cases of Lyme disease in Nova Scotia nearly tripled in 2013 over the
previous year.
The
new research shows these problems with tick-borne disease have been around for
millions of years.
Bacteria
are an ancient group that date back about 3.6 billion years, almost as old as
the planet itself. As soft-bodied organisms they are rarely preserved in the
fossil record, but an exception is amber, which begins as a free-flowing tree
sap that traps and preserves material in exquisite detail as it slowly turns
into a semi-precious mineral.
A
series of four ticks from Dominican amber were analyzed in this study,
revealing a large population of spirochete-like cells that most closely
resemble those of the present-day Borrelia species. In a
separate report, Poinar found cells that resemble Rickettsiabacteria,
the cause of Rocky Mountain spotted fever and related illnesses. This is the
oldest fossil evidence of ticks associated with such bacteria.
In
30 years of studying diseases revealed in the fossil record, Poinar has
documented the ancient presence of such diseases as malaria, leishmania, and
others. Evidence suggests that dinosaurs could have been infected with Rickettsial pathogens.
Humans
have probably been getting diseases, including Lyme disease, from tick-borne
bacteria as long as there have been humans, Poinar said. The oldest documented
case is the Tyrolean iceman, a 5,300-year-old mummy found in a glacier in the
Italian Alps.
"Before
he was frozen in the glacier, the iceman was probably already in misery from
Lyme disease," Poinar said. "He had a lot of health problems and was
really a mess."
Story Source:
The
above story is based on materials provided by Oregon State University. Note: Materials may be
edited for content and length.
Journal References:
1.
George Poinar. Spirochete-like
cells in a Dominican amberAmbylommatick (Arachnida: Ixodidae). Historical
Biology, 2014; 1 DOI:10.1080/08912963.2014.897699
2.
George Poinar. Rickettsial-like
cells in the Cretaceous tick, Cornupalpatum burmanicum (Ixodida: Ixodidae). Cretaceous
Research, 2014; DOI:10.1016/j.cretres.2014.02.007
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Chicago
Oregon State University. "Amber discovery indicates Lyme
disease is older than human race." Science
Daily, 29 May 2014.
<www.sciencedaily.com/releases/2014/05/140529142538.htm>.
