Deer nasal bot flies
Nasal bots are the larvae of the bot fly (Cephenemyia sp.) and are common parasites that are found in the nasal passages of deer.
Adult female flies deposit eggs in the nostrils of the deer. The eggs hatch into larvae and then pass through several stages of development and growth while living in the deer.
Although quite large -- up to 1 1/2 inches -- and unpleasant looking in the final stages of development, nasal bots cause little harm to individual deer. Some deer may be observed snorting or shaking their heads as the larvae may be irritating to the nasal passages.
Nasal bots are not a significant health issue for deer and individual affected deer recover after the larvae finish development into adult flies and leave the body.
Nasal bots do not infect humans. Botflies do not affect meat quality and it is safe to eat meat from an animal infected with bots.