Oestrinae

Oestrinae is a subfamily of the bot fly family Oestridae. Members are obligate parasitic flies whose larvae develop in the nasal cavities and sinuses of mammals, particularly ungulates. The subfamily includes several genera, with Oestrus (sheep nasal bot), Cephenemyia, and Pharyngomyia among the best known for infesting domestic and wild ruminants.

Distribution and life cycle: Species occur wherever suitable hosts are found, with regional species varying by geography. Females typically lay eggs or first-instar larvae near the nostrils or on the lips of a host. Larvae hatch and migrate into the nasal cavities and paranasal sinuses, where they feed and grow through successive instars for months. Mature larvae exit to the environment and pupate in soil; adults emerge, mate, and the cycle repeats. Adults generally do not feed.

Host impact and diagnosis: Infections mainly affect sheep, goats, deer and other ruminants. Inflammation of nasal passages, sneezing, nasal discharge, crusting, and reduced weight gain are typical. Severe infestations can cause secondary infections or obstruction. Diagnosis is based on clinical signs and, post-mortem or larval collection, identification of characteristic larvae; adult morphology can confirm genus.

Control: Management includes strategic anthelmintic treatment effective against larval stages, fall or winter treatment plans, and minimizing exposure during peak transmission periods.

Taxonomy: Oestrinae is one of several subfamilies within Oestridae; others include Gasterophilinae (stomach bots) and Hypodermatinae (cattle bots).