The respiratory and allergic manifestations of human myiasis caused by larvae of the sheep bot fly ( Oestrus ovis ): a report of 33 pharyngeal cases from southern Iran

Myiasis--the feeding of fly larvae on living mammals--may have various presentations, depending on the tissues or organs involved. The respiratory and non-respiratory manifestations of human pharyngeal myiasis caused by Oestrus ovis larvae in 33 patients from the Fars province, in southern Iran, are described here. All but one of the 33 cases were male and all lived in rural areas, in close contact with sheep and goats. The myiasis only occurred in spring and summer (April-September). Symptoms always appeared abruptly, all of the cases sensing the presence of foreign bodies in their throats, a burning sensation and itching in the throat being followed by cough and then various other respiratory, nasal, aural, and eye manifestations. Fly larvae were observed directly in the throats of five patients, and recovered in throat washings from all 33 cases. All of the larvae were identified as those of the sheep bot fly (Oestrus ovis). Removal of the larvae, by irrigation of the throat with a large volume of normal saline, provided an effective and fast treatment. In Iran at least, myiasis caused by Oestrus ovis larvae should be considered an occupational disease among farmers who keep sheep and goats.