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Jun 12, 2001
By Gene Emery
BOSTON (Reuters) - A one-dose treatment with the antibiotic
doxycycline, given soon after the bite of a
deer tick, can prevent Lyme disease, researchers reported on Tuesday as the
season for getting the crippling ailment draws near.
Until now, doctors in the U.S. Northeast have traditionally
given antibiotics for two or three weeks
once they see a telltale rash surrounding a tick bite, hoping to prevent the
flu-like symptoms of Lyme.
The study is scheduled to appear in the July 12 issue of the
New England Journal of Medicine, but the editors decided to release the results
Tuesday because the information could be important to doctors confronted with
Lyme.
Incidents of Lyme, which is contracted through tick bites and
is characterized by muscle pain, joint aches
and fatigue, usually rise in the summer months when people tend to be outdoors
more.
More than 90 percent of all Lyme disease cases in the United
States occur in just nine states: Massachusetts, Connecticut, Rhode Island, New
York, New Jersey, Pennsylvania, Delaware, Maryland and
Wisconsin. Lyme is also found in Europe and Asia, but the method of transmitting
the disease may be different, researchers said.
In an editorial in the Journal, Dr. Eugene Shapiro of the
Yale University School of Medicine said the findings illustrate the importance
of preventing Lyme by routinely checking for the tiny ticks that carry the
disease.
The researchers discovered that Lyme only appeared if the
tick had been attached to the skin for 72 hours or longer. In addition, there
was no risk of Lyme if the tick was flat and had not become engorged with blood.
HIGH RATES IN WESTCHESTER
The test of doxycycline, led by Dr. Robert
Nadelman of the New York Medical College, was done in Westchester County, New
York, which has one of the highest rates of Lyme disease in the world. All of
the volunteers had removed deer ticks that had become attached to their bodies.
Nadelman and his colleagues found that only 1 out of 235
people who got a single 200 milligram dose of the antibiotic developed Lyme,
compared to 8 of 247 subjects -- 3.2 percent -- given a placebo.
One pill, they concluded, "can prevent the development
of Lyme disease." But the drug tended to cause nausea in 15 percent of the
recipients and vomiting in 6 percent.
If the results are confirmed, "it would be necessary to
give doxycycline to about 40 persons to prevent one case of Lyme disease,"
Shapiro said in his editorial.
But in other areas of the United States, Lyme is too rare to
routinely warrant treatment after a bite.
He also said it might be wise to test other antibiotics to
see if they have fewer side effects than doxycycline, which is manufactured by
several companies.
In a second study, also released early by the Journal, a
research team found that people suffering from the long-term effects of Lyme
disease are not helped by aggressive treatment with both oral and intravenous
antibiotics is ineffective.
Dr. Mark Klempner of New England Medical Center and his
colleagues tested 90 days of antibiotic treatment in 129 patients who had been
suffering from symptoms for at least six months after receiving
initial treatment for Lyme disease.
The test was halted early because preliminary results showed
no benefits to the treatment.
Shapiro, in his editorial, said the risk of Lyme has been
exaggerated to the point of near-hysteria, noting that only 3.2 percent of the
untreated patients in the Nadelman study developed the illness.
People should seek treatment if a telltale circular rash
appears around the site of a tick bite, he said, but
"there is substantial evidence that in the vast majority of patients with
Lyme disease, conventional treatment with antimicrobials is very effective and
the long-term outcomes are excellent."
http://www.nejm.org/earlyrelease/feature.asp?strxmlfilename=20010712/01071201
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