Contagious Footrot

Also known as:

Scald

Description

It is an economically important disease causing lameness in sheep. The disease is associated with under-running of the hoof and a typical 'odour'. Footrot is caused by Dichelobacter nodosus together with Fusobacterium necrophorum. Moisture and trauma allowF. necrophorum to enter which aids bacterial penetration of the epidermis by D. nodosus resulting in necrosis and inflammation. Carrier animals are a major source of infection and are difficult to find as they are often sub clinical cases.

Signalment

Affects sheep, particularly those kept in wet warm conditions.

Diagnosis

Can be made on a history of lameness and rapid spread amongst the flock in combination with clinical signs.

Clinical Signs

Lameness is often the first clinical sign to be noted and can vary in severity. Under-running of the horn is present and there is often a necrotic discharge which causes the characteristic foul 'odour'.

Pathology

Grossly: Early lesions are red, moist, swollen and interdigital skin is eroded. This spreads to epidermal matrix of the hoof leading to separation of the horn and malodorous exudate. Regeneration is attempted as germinal epithelium is not destroyed. Chronic infections can result in a long misshapen hoof. Benign footrot (scald)- only interdigital skin affected, slight separation of heel horn Mostly the type occuring in cattle

Treatment

A single dose of antibiotics ideally penicillin or oxytetracycline.