If you've ever seen a hole in your dog's fur and wondered what it was, you may be concerned about Cuterebra, also known as warbles. Cuterebra is a type of botfly in dogs that lays eggs on the skin and fur of dogs. The eggs hatch and larvae burrow into the skin, feeding off tissue fluids before rupturing from the host animal. Initially, you will notice an inflamed lump underneath your dog's skin. The botfly in dogs then creates a large gaping hole in your dog's skin, which can be alarming for dog owners. If you're concerned about this happening to your pup or want to learn more about how Cuterebra affects dogs, read our article here!
What is a botfly in dogs (Cuterebra)?
Cuterebriasis (Warbles) is an infestation of mammals by botfly Cuterebra larvae and these larvae are normal parasites of rodents and rabbits. Cuterebra is a species of botfly that lives throughout North America.
How do dogs become infected with Cuterebra?
Adult botflies lay eggs at the entrance of rodent and rabbit burrows during the summer months. Eggs are stimulated to hatch from the warmth of the animal’s body as it enters the burrow. Larvae attach themselves to the animal’s coat and enter through any opening. The larvae migrate through the host and usually terminate in the tissue beneath the skin. After approximately 3-4 weeks, the larva forms a visible nodule (a warble) with an external breathing hole. After completing development, the larva exits the host and pupates on the ground.
Dogs may become infected by coming into contact with botfly larvae that is present in rabbit or rodent burrows. Curious dogs sniff and stick their heads in burrows resulting in transmission and subsequent infection. The larva can enter through the oral cavity, nose, wounds, or any other opening.
Symptoms to look out for if you think your dog has Cuterebra
The path of larval migration determines whether abnormalities are found in dogs suffering from Cuterebriasis. Migration beneath the skin is quite typical, resulting in a warble and perhaps a secondary bacterial infection. A small lump underneath the skin with an opening (breathing hole) may be noted. Botfly warbles are most commonly found on the head and necks of dogs. Larvae may also be visible through the breathing hole. If the botfly larva invades the nose and respiratory system, an infected dog will sneeze, have nasal discharge, and cough, typical symptoms.
In some cases, you may actually see a small worm coming out of your dog's skin, particularly from a bump on your dog's skin with a tiny hole in the center.
What treatments are available for dogs with Cuterebra?
If the larvae are in an accessible location, the main treatment is to remove them. The breathing pore is carefully surgically enlarged to allow for the removal of the larva in one intact piece. Foreign body reaction, secondary infection, and abscess formation can all result from incomplete removal of the larva during surgery.
In dogs where the location of the Cuterebra larva is not surgically accessible, such as in the central nervous system (CNS), your veterinarian will prescribe anti-parasitic medications such as ivermectin.
An antihistamine such as diphenhydramine should be administered prior to and during the anti-parasitic treatments to prevent an allergic reaction to the dying larva.
Prevention tips to keep your dog safe from botfly larval infections
Keeping your dogs away from rabbit and rodent burrows is the best prevention. If you live in an area where botflies are common, inspect your dog’s coat regularly for any lumps or swelling. If you find a lump, have your veterinarian take a look to determine if it is a warble caused by Cuterebra.
Dogs can become infected by a botfly larva that is present in rabbit or rodent burrows. A small lump underneath the skin with an opening (breathing hole) may be noted. If your dog has a botfly, they will have sneezing, nasal discharge, and coughing as typical symptoms. The best prevention for botfly infections is to keep your dogs away from rabbit and rodent burrows!