NADIS disease bulletins are written specifically for farmers, to increase awareness of prevalent conditions and promote disease prevention and control, in order to benefit animal health and welfare.

Farmers are advised to discuss their individual farm circumstances with their veterinary surgeon.

Ringworm in sheep

Over the past few months there have been several reports of ringworm in sheep flocks due to skin infection by the fungus Trichophyton verrucosum. Most reports have been from pedigree flocks of ram lambs, and in some cases up to 70% of the lambs in a flock have been affected.

Ringworm in sheep is characterised by clearly demarcated, 1 – 10 cm² areas of hair loss, covered by dry wart-like crusts on the ears, face and wool-less parts of the neck. Affected animals do not excessively rub or scrape at the lesions. Where the disease has been seen in shearling animals, it has been characterised by raised 4 – 6 cm diameter scabs over the wool-covered parts of the body. When the matted wool covering the lesions is removed, the underlying skin appears inflamed and bleeds readily. Lesions in shearling rams have appeared about 6 weeks after shearing and in some cases the disease has persisted for 6 months.

Ringworm can cause unpleasant skin disease in man, so care should be taken when handling affected animals.

The treatment of ringworm outbreaks in sheep is problematic. An oral ringworm therapy used to be effective for the treatment of the disease in calves, but its use is no longer permitted in food producing animals within the European Community. Topical ringworm treatments may reduce the duration of lesions on the face, but appear to be ineffective for the treatment of body lesions, possibly because the exudate-matted fleece prevents contact between the drug and fungus.

Management of outbreaks of ringworm, therefore, depends on prompt recognition of the clinical signs, isolation of affected animals and treatment of troughs and barriers with a suitable disinfectant. Precautions are required at shearing to avoid spread of infection from lesions on the face to the body of sheep. Your vet can provide further advice about the diagnosis and management of ringworm in your sheep flock.

Neil Sargison BA VetMB DSHP FRCVS