Acutely lame sheep in western Queensland
Unusual presentation:
Acute lameness in recently introduced sheep.
Above: Interdigital dermatitis and some cases with under-running of coronary band.
Time and location: March 2020, western Queensland.
Case definition: Acute lameness of sheep.
Disease mapping: 250 sheep trucked from the coast to central Queensland. No signs at the time of unloading. About 10% acutely lame by the end of the week.
Gross findings: Hoof and foot lesions visible in several sheep from a mild interdigital dermatitis to significant under-running of the coronary band. One ewe also had respiratory signs, nasal discharge and pyrexia. Swabs collected. Bloods submitted from the sick ewe and a sheep with more severe foot lesions on advice from the laboratory.
Laboratory findings: Foot swabs grew Fusobacterium necrophorum (Dichelobacter nodosus not isolated). Both sheep PCR negative for Bluetongue virus, one was seropositive (regarded by the laboratory as not unusual for sheep from that region).
Animal / management / environment risk factors: Pathogens isolated are common in wet muddy conditions. Transport conditions could exacerbate spread.
Recommendations to the producer: Isolate sheep and monitor every 2 days. Give antibiotics (Alamycin LA) to affected animals. (Note lesions healed rapidly after treatment.) In future (if introducing animals from wet coastal regions), consider using footbath or close monitoring post arrival.