Report of Oestrus sp. larvae in the nasal cavity of sheep from the Azores archipelago.

The presence of Oestrus sp. in sheep is a parasitic condition that has been widely reported in most regions of the world. However, to date, there are no documented records of this parasitosis in the Azores archipelago, Portugal. This study describes the first occurrence of Oestrus sp. in a sheep on Terceira Island, Azores, identified during necropsy, with the animal showed signs of lethargy, anorexia and loss of body condition before death, which may have resulted from multiple factors rather than exclusively from Oestrus sp. Infestation. During the post-mortem examination, five Oestrus sp. larvae were found in the animal's nasal cavities and paranasal sinuses. This finding confirms the presence of this parasite on Terceira Island, suggesting a possible recent introduction or under-reporting of its occurrence in local sheep.