Healthy Indoors
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Each mouse excretes urine with a character-
istic mixture of odors. Members of a "clan" can
distinguish each other as well as enemies by the
odors in their urine trails. Females indicate when
they are ready to mate, and the dominant mouse
lets other members of the mouse community
know who he is and where he's going.
There is a scientific reason why homes that
have endured long-term mouse infestations have
a lingering animal odor, characteristic of mice.
Odors can be volatile (can evaporate at room
temperature), but the odor of mouse urine is so
MUPs work like the chemical (cyclodextrin) in
Fabreze, which is a large molecule with a cav-
ity in the middle; odor molecules are "sucked"
into the hole and reduced in strength. MUPs
are a principal source of mouse allergens.
Mouse urine trails on basement wires
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Mouse urine trails on PVC pipes
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Mouse urine trails on basement shelf: the rodents trav-
eled around boxes that used to be on the shelf
May Indoor Air Investigations LLC
Mouse droppings on top of foundation wall
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important in "mouse talk" that there is a whole set
of characteristic proteins (called major urinary pro-
teins or MUPs) that mice secrete with their urine
in order to trap the odor molecules and thus make
them persist longer than they would have if simply
excreted onto a surface.
