The rodent or rabbit botfly, known as the opportunistic, parasitic Cuterebra or warble, also infects cats, dogs and ferrets. Bee-like in appearance, the adult Cuterebra fly lays its eggs at the entrances to animal burrows or along well used animal trails. The eggs respond to the heat of a passing animal and easily attach to its fur.
Once on the fur the eggs hatch into larvae, the parasite gains entrance into the host's body during grooming practices. Or if the animal suffers from an open wound the Cuterebra will utilise the opening to enter the animal's system. Within the system, the larvae migrate to locations around the head, body or neck of the animals. The larvae have also been known to infect the brain, eyes and throat of the animal.
Once in their area of choice they begin to grow just under the skin. In their subcutaneous location they breath utilising a breathing pore. Over the course of 30 days the larvae mature.The larvae grow to approximately 1/2 inch in length and a few have been known to attain a length of 1 inch. The skin forms a nodule over the larvae and often secretes body fluid from the breathing pore.
Upon maturity, the larvae break out of the skin's surface to pupate in the soil and emerge as mature Caterebra botflies ready to breed. The stage of pupation is dependent upon temperature. The period can be quick and last only 28 days or it may take as long as 11 months, according to the Michigan Department of Natural Resources and Environment.
Mating and Egg Production
Within a few days of the pupate emerging into a mature Cuterebra botfly, mating will occur. The male Cuterebra awaits the arrival of a female by taking up residence on plants or shrubs. When a female locates a male she decides if mating occurs or not. If she is receptive to the male then mating will occur in flight. The female will deposit eggs in various locations. Most egg catches consist of 5 to 15 eggs. The female will lay around 2,000 eggs during her lifespan, according to the Merck Veterinary Manual.
After mating the Cuterebra will die within 14 days. Their adult lifespan and mating occurs either in the spring or the summer months. When a pet is infected with a Cuterebra larvae home removal should never be undertaken. Always take the pet to the veterinarian. If complete removal of the larvae is not achieved an infection or abscess will persist in the location.