Semi-quantitative appreciation of upper respiratory mucosae in sheep naturally infected by Oestrus ovis (Linne 1761)

Twenty seven gross and microscopic morphological alterations suspected to b e relative to Oestrus ovis infection have been studied in epithelium of nas al septum, turbinates and frontal sinuses. Nine non infected lambs, 77 natu rally infected ewes with a mean of 12,8 larvae and 61 non infected ewes but living in infected area have been sampled at random in slaugther house. Mi croscopic lesions observed in infected ewes were limited : a moderate epith elial desquamation was present without increasing the depth of epithelium. Subepithelial and inter-glandular layers showed slight mononuclear infiltra tions, not present in non-infected animals. A low level of oedema was also present in inter-glandular layer presumably related to mast-cells and eosin ophils infiltration. At the glandular level, there was also mononuclear inf iltrations, and the secretion was increased. Finally, for all animals, whet her infected or not, a moderate capillary dilatation was observed in all an atomic sites.