Flystrike

Flystrike, also known as fly strike or myiasis, is a potentially fatal disease that is common in the warmer months of the year. It is caused by several types of insects that will lay eggs in the wounded skin of mammals, and the maggots hatching from the eggs then digest living tissue.

Species that cause flystrike in rabbits include the blowflies Lucilia sericata, Calliphora sp., the grey flesh fly Wohlfahrtia sp., the common screwworm fly Callitroga sp., and from the botfly Cuterebra sp (Western hemisphere only). While not usual, the common house fly (Musca domestica) can also cause flystrike when it lays eggs in matted fur coated in feces, and the hatched maggots rapidly move to an infected wound.

Treatment and prevention
Initial treatment for flystrike involves clipping the fur and cleaning any affected areas. Then, the maggots are manually removed, and the wounds are flushed with a dilute chlorhexidine or povidone-iodine cleanser. Cuterebra larvae should be removed via their breathing hole either surgically or by using ivermectin.

Supportive treatment should be aggressive with therapy for toxic shock and ivermectin or imidacloprid to kill any additional maggots or larvae that cannot be removed.

The underlying cause of poopy butt should be addressed as well, and regular inspection of the rabbit's bottom and protection from exposure to flies is important to preventing flystrike.

Topical cyromazine (Rearguard, Novartis) applied as a 6% solution topically every 6 to 10 weeks can be used as a preventative for myiasis.