Cuterebra Larvae, Cuterebriasis

These parasites in the skin are the larvae or maggot of the fly Cuterebra. The fly lays its sticky eggs on the long blades of grass around burrows in the ground. Small animals such as rabbits passing through the opening to the burrow or cats who stick their heads into the burrows looking for the rabbits, get the eggs caught on their fur around their head and face. The eggs hatch and the larvae crawls down into the fur and burrow into the skin. It creates a cyst that grows larger as the larva enlarges almost an inch in length. The parasite breathes through an opening in the skin. Eventually the skin ruptures and the larva drops out to complete its cycle.

By themselves, the larva and the cyst don't cause much of a problem to the cat except for a mild localized infection. However, most cat owners understandably object when they see a huge maggot moving around the skin and request its removal. This should be done only by a veterinarian because rupture of the maggot can cause an anaphylactic reaction.