Sorry to hassle you again after sending the glowing scorpion
from the Grand Canyon, but I thought you might want some cuterebra
photos too. I am a veterinarian in Colorado Springs,
CO, and I commonly see cuterebra larvae (my personal favorite
clinical entity) in dogs, cats, ferrets, and rabbits from
late July to early September. The pet usually has a
mound on the skin with a perfectly round hole on top through
which you can see the larva moving. Sometimes there
is a little discharge, but in general it does not seem to
be too irritating. Imagine the surprise when the owner
squeezes at the mound and out pops this little larva!
It sure is dramatic, but they don’t really cause any
serious health problems. When I see them I use a little
local anesthesia around the opening and then enlarge it with
a scalpel blade before gently squeezing the larva out because
the hole is often smaller than the larva and if you are too
forcefull you can squeeze the larva inside out, leaving the
cuticle to fester under the skin. It is unusual for me to
see more than one on a pet at one time, since most pets
are not the preferred hosts, but this little Yorkie had
10 of them. The owners squeezed most of them out themselves
(thus taking away all my fun) and fortunately all the larvae
came out intact for them. Cattle also have a cuterebra
species that affects them and the common name for the
condition is ‘Warbles’. The quick and dirty way to get
rid of the larvae in cattle is to place a soda bottle upside
down with the mouth over the opening and then quickly hit
the bottom of the bottle so that the larva shoots up into

Hi Anne,
Getting such an informative letter would never be a hassle.
Thanks for your expert account of a Bot Fly Larvae infestation
and treatment recommendation. The typical hosts for North
American Bot Flies are rodents like rabbits and squirrels.
There is a Human Bot Fly found in Central America.

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