LONDON, Sept. 18 (UPI) -- Building on a longstanding theory
that multiple sclerosis is triggered by an as-yet-undiscovered virus, a
British researcher has assembled evidence from dozens of different studies
he claims support his hypothesis MS might be transmitted primarily by sexual
contact.
A number of experts contacted by United Press International questioned
the validity of the data used to support the theory, however.
"This is a new way of looking at multiple sclerosis -- it provides a
testable hypothesis," Christopher Hawkes, a neurologist at London's Institute
for Neurology and the expounder of the idea, told UPI.
"It's a sensitive subject, because if you had MS and you had a perfectly
respectable upbringing, respectable life, with just one or two partners
before you married, you wouldn't like to think it had the same stigma as
something like syphilis," Hawkes said.
Sufferers of multiple sclerosis progressively develop scarring of the
myelin, the protective sheath that covers the nerves. The condition leads
to muscle weakness, blurred vision, slurred speech, tremors and other symptoms.
MS affects as many as 500,000 people in the United States. There is no
known cure.
Hawkes' research turned up four small MS epidemics that occurred on
the Faroe, Orkney and Shetland islands and in Iceland following large influxes
of Allied troops during World War II. This suggests sexual activity between
women on the islands -- who previously had lower rates of infection --
and troops from geographic regions with higher rates of infection led to
the outbreaks. There are questions about the accuracy of some of the relevant
statistics, however.
Hawkes suggested -- as have other researchers -- that because the human
T-Cell lymphotrophic virus-1, or HTLV-1, has been shown to cause a disease
with symptoms quite similar to MS, a viral agent might be at work and might
be transmitted sexually.
Among the studies cited by Hawkes are one done in Kashmir, India and
another in Thugbah, Saudi Arabia, where extramarital sexual relations are
thought to be relatively rare. Both showed extremely low rates of MS.
In contrast, research shows increased MS rates in western countries
following the introduction of birth control pills and less use of barrier
methods, beginning in the 1970s, he said.
"There is absolutely no data to support (this) hypothesis," Lauren Krupp,
a neurologist and co-director of the MS center at the State University
of New York at Stony Brook, told UPI. "For every point that the author
raises to support his argument there is a very strong counter-argument,"
she said. "The specific kinds of things you would look for to support his
argument aren't found in the existing data in the literature."
Krupp, who also is a spokeswoman for the National Multiple Sclerosis
Society, cited a study -- also used by Hawkes -- of 13,000 married couples
with one spouse contracting MS but showing no evidence of a higher rate
of transmission to the other spouse.
Hawkes responded he thinks susceptibility to the disease is higher at
younger ages and some studies of couples do show five times the rate expected
in the general population. In addition, he said, in tropical spastic paraplegia,
the disease caused by HTLV-1 -- which is known to be sexually transmitted
-- transmission among married couples is relatively low. The same may be
true for MS.
He acknowledged, however, that a virus, if it exists, also might need
to act along with genetic susceptibility -- generally thought to be a key
ingredient to developing the disease. "I say let's have a look at it rather
than talking it into the ground. ... You've got to keep an open mind because
nobody has the answer on MS," Hawkes said.
Although there may very well be a viral agent, or multiple viral agents,
Krupp said, increased rates following higher levels of troops in isolated
communities could be explained by viral transmission that was not necessarily
sexual -- something Hawkes agrees is possible.
Graeme Stewart, an immunologist at Westmead Hospital in Sydney, Australia,
told UPI, "The sexually transmitted infection hypothesis in multiple sclerosis
is of low credibility."
Hawkes theory will be published in the October issue of the Journal
of Neurology, Neurosurgery and Psychiatry.
Reported by Joe Grossman, UPI Science News, in Santa Cruz,
Calif.)
Copyright © 2002 United Press International