Reference Work Entry

Encyclopedia of Parasitology

pp 1241-1243

Respiratory System Diseases, Ruminants

The common clinical signs and pathology of parasitic infections of the respiratory system of ruminants are summarized in Table 1.

Nasal Cavity and Sinuses

The larvae of a number of flies of the family Oestridae are parasites of nasal cavities and sinuses of ruminants. The most ubiquitous is the nasal botfly of sheep and goats, Oestrus ovis. The flies cause great stress when they attack the sheep to deposit larvae near the nostrils of the host, a process which significantly interferes with grazing and rumination. The larvae which develop in the nasal cavities may get up to 3 cm in length and cause severe discomfort, partly because of the damage caused by the oral hooks and cuticular spines of the larvae, but also because of hypersensitivity​ phenomena. Nasal discharge and sneezing are common features in affected sheep, with caked dust obstructing the nostrils. Head shaking and nose rubbing may sometimes be seen. Extension to the cranial cavity via the ethmoid c ...

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