We are starting to feel a little nip in the air as fall is starting to peak around the corner. During this time in the year, it might not be too uncommon for you to find a weird draining hole or pimple on the side of your dog. On closer inspection, it will appear as though the head of the pimple is moving! That is unfortunately no pimple, it’s actually the larvae of a bot fly that made itself a cozy, little home underneath your dog’s skin.
The more technical name of the bot fly is call Cuterebra. The adult female flies will deposit their eggs into animal nests and along common pathways in the woods that we take our pets for a walk. Animals become infested with the larvae when the eggs detect a nearby host. The eggs will then hatch into larvae and latch onto your pet. The larvae will enter the body when the host grooms itself or if there is already an open wound on the host. From there, the Cuterebra will migrate to subcutaneous spots on your pet and create a breathing pore where that spot will commonly become infected and secrete purulent material from the site. Gross!
Not only can you find these larvae on your dog, but outdoor cats and ferrets are also prone to a bot fly infestation. More rare areas a Cuterebra can migrate to include the eyelids, pharynx, nasal airways, and even the brain. Your pets will commonly seem to be over-grooming in one particular area where the skin is swollen and the hair is matted when infested with a larvae. It is very important that when you notice a Cuterebra in your animal, to not squeeze the larvae out. Manually expressing the larvae can cause it to rupture and lead to either an anaphylactic reaction or residual abscess formation if a piece of larvae is left inside the host.
Treatment for a larvae infestation requires careful extraction by your veterinarian. Commonly, a local anesthetic will be applied to the area to enlarge the breathing pore with a scalpel blade. Once the larva is removed in one whole piece, the previous home of the bot fly will be rinsed out and antibiotics will be prescribed to clear up the infected skin. Stay vigilant and keep a close eye on your pet this time of year for any moving pimples. Your vet will help you kick these little freeloaders out and keep your animal’s skin coat healthy and porous free.