Oestrus

a genus of widely distributed nonbloodsucking flies, occurring wherever sheep and goats are raised. The parasitic larvae of O. ovis, the sheep nostril fly, may occasionally and accidentally infect humans. By means of large mouth hooks, it attaches itself to the conjunctiva of the eye, causing a painful MYIASIS that may result in loss of sight. This is an occupational disease of shepherds. Larvae can be removed with forceps following anaesthesia.