author(s)
M Prabhu, PC Sakthivel, N Prema, R Anilkumar and M Iyue

abstract
The sheep nasal bot, Oestrus ovis, is commonly found in sheep and occasionally in goats that rarely migrate into the brain and cause false gid. In the present study, based on the clinical illness, pathology and parasitological findings, the natural incidence of oestrosis in an organized flock is described. A total of 268 sheep showed the clinical signs during 2013 and 2014 with the corresponding prevalence of 12.31 and 7.39%, respectively. Affected animals showed sneezing, rhinitis, seromucous nasal discharge, epistaxis, restlessness and rarely nervous incoordination. The bots were recovered from 13 animals from nasal cavity, cranial cavity and trachea during necropsy. Lung abscess and suppurative pneumonia was observed by histopathology. One animal died of false gid. The incidence was more common during rainy season particularly south west monsoon period (n=232) followed by summer (n=22) and lowest during the winter season (n=2). The clinical illness was more pronounced in adult animals compared to young ones. The affected animals were treated with Ivermectin @ 200 µg per kg body weight with uneventful recovery.