The occurrence of Pseudomonas aeruginosa in fleece washings from sheep affected and unaffected with fleece rot

Fleece rot is an exudative bacterial dermatitis in sheep associated with and initiated by prolonged wetting of the skin. It is the major predisposing disease for flystrike (cutaneous myasis). Based on limited data in the literature, P. aeruginosa is considered to be the main causative organism of fleece rot. This study investigated the occurrence of P. aeruginosa in fleece washings from sheep affected and unaffected with fleece rot under field conditions. Three field surveys of a total of 1568 sheep showed that 646 (41%) were affected with fleece rot and of these 646 sheep, P. aeruginosa could not be detected in 554 (86%). This suggests that other fleece bacteria play a significant role in fleece rot. However, the surveys consistently showed that the presence of P. aeruginosa was associated with increased severity of fleece rot and subsequent flystrike. Although it might only contribute in part to the disease complex, the importance of P. aeruginosa can not be underestimated and warrants consideration for inclusion in future fleece rot vaccines.