Spore counts soar when evergreens are brought indoors, researchers
find
FRIDAY, Nov. 16 (HealthDay
News) -- While bringing home a live Christmas tree marks the beginning of the
holiday season for many, the mold that thrives on its branches can trigger
weeks of suffering for some, a new study shows.
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Connecticut researchers
have found that the mold count from a live Christmas tree rose to five times
the normal level two weeks after the tree was brought indoors, and that can
prove problematic for people with mold allergies. Their research was presented
this week at the American College of Allergy, Asthma & Immunology annual
meeting, in Dallas.
"Christmas trees are
another possible source of mold exposure during the holiday season," said
study co-author Philip Hemmers, an allergist and immunologist with St.
Vincent's Medical Center in Bridgeport, Conn. "Mold allergies peak in the
fall, and we see a second peak with a lot of our mold-sensitive patients during
the holiday season. Our finding correlates with this second peak of mold
sensitivity."
The researchers studied
the mold growth of a live Christmas tree in a house in Connecticut. Mold
reproduce by releasing spores into the air, so after the live Christmas tree
was brought inside the house and decorated, the researchers measured mold spore
counts. These counts were taken 12 times over a two-week period between Dec. 24
and Jan. 6. The researchers did not assess the types of mold or whether these
molds triggered allergic symptoms in people living in the house.
The study found that the
mold spore count was 800 spores per square meter (m3) for the first three days.
Normal spore counts are less than 1,000 spores/m3, said Hemmers. However, the
spore count rose after day four, reaching a maximum of 5,000 spores/m3 by day
14.
"This mold spore
count is five times above normal. These high levels have been correlated with
allergic rhinitis and an increased rate of asthma symptoms and asthma-related
hospitalization in other studies," said Hemmers. "So if you don't
feel well during the holidays, consider the Christmas tree as a possible source
of allergies."
Hemmers recommended that
people with mold sensitivity keep a live Christmas tree in the house for only
four to seven days. An artificial tree may be a better option for people with
mold allergies, he added, but they carry their own set of problems, especially
if they've been stored in the attic or basement where they can collect dust and
mold.
Although Christmas trees
are not a problem for most people with allergies, said Dr. David Khan, an
associate professor of internal medicine at the University of Texas
Southwestern Medical Center in Dallas, there are things you can do to minimize
their impact.
"If one is
mold-allergic, running an air cleaner in the same room as the tree could
theoretically reduce the mold exposure, but this has not been studied," he
said. "For some people who are sensitive to odors, the aroma from the
tree, which most people like, could irritate their nose and cause symptoms. For
these people, avoiding live trees may be best."
Before people start
avoiding live Christmas trees because of their mold growth, more research needs
to be done, said Dr. Dennis Ownby, a professor of pediatrics and medicine at
the Medical College of Georgia, in Augusta. Since this study only looked at a
single tree in one home, more homes with trees should be investigated, as well
as the types of mold found and whether those molds trigger allergies. He added
that the researchers should also measure mold counts outside the home and
correlate those to indoor mold counts.
Hemmers said that the outdoor
mold count was likely low, since the study was done during the winter. The
research team does plan to do further work this Christmas season by looking at
more homes and the types of mold found.
In addition to Christmas
trees, there are other potential holiday allergens, said Dr. James Sublett,
section chief of Pediatric Allergy at the University of Louisville School of
Medicine in Kentucky. These can include foods consumed at holiday parties, such
as nuts and shellfish, and Christmas ornaments and lights that have been
contaminated with dust or mold.
"Store Christmas
decorations in plastic containers that you can wipe off, since cardboard can
potentially have mold," he advised. "Also wear a N95 dust mask when
bringing stuff out of storage."
