Old-Time Mosquito Remedy May Work Against Ticks,
Too By Luis
Pons January 26, 2007
A granddad's wisdom, already helpful in the fight against mosquitoes,
may also prove useful in battling disease-spreading ticks.
Last year, Agricultural Research Service (ARS) scientists in Oxford, Miss., isolated
compounds from a plant called American beautyberry that enable its crushed
leaves to repel mosquitoes.
This work, led by chemist
Cantrell at the ARS
Products Utilization Research Unit in Oxford, was inspired by a tip another
Bryson in Stoneville, Miss.got long ago from his grandfather: that
beautyberry was used in northeastern Mississippi to protect people and
farm-work animals from biting bugs.
Now ARS scientists in Beltsville, Md., have shown that two beautyberry
compoundscallicarpenal and intermedeolmay effectively repel
blacklegged ticks as well.
Blacklegged ticks are the principal carrier of bacteria that in humans
cause Lyme disease, an affliction known for its fevers, headaches and
bull's-eye rash. Left untreated, this disease can cause severe and chronic
Blacklegged ticks, Ixodes
scapularis, are the principal carrier of bacteria that cause Lyme disease
in humans. Preliminary studies by ARS scientists in Maryland have shown that
compounds from American beautyberry plants may have use as repellents against
them. Click the images for more information about them.
Carroll, in the
Parasitic Diseases Laboratory, Beltsville, and
Klun, in the
Affecting Insect Behavior Laboratory, also in Beltsville, tested the
compounds by administering them to cloth strips wrapped around a person's
finger in dosages at which the commercial repellent DEET repels ticks.
The treated strips repelled more than 95 percent of blacklegged tick
Callicarpenal did especially well in a separate duration test,
repelling all the blacklegged ticks tested for three hours after application,
and 53 percent after four hours.
The researchers also tested the natural compounds against nymphs of
lone star ticks, which transmit potentially serious human diseases known as
The two compounds, as well as DEET, were considerably more potent
against blacklegged ticks than against lone star ticks. An experimental
repellent developed by ARS and known as SS220 was most effective against the
lone star variety.
While the findings are preliminary, the beautyberry compounds' usage
history leads Carroll to believe that callicarpenal and intermedeol have
potential for human use.
ARS is the U.S. Department of
Agriculture's chief scientific research agency.