The beagle is a breed of small hound that is similar in appearance to the much larger foxhound. The beagle is a scent hound, developed primarily for hunting hare (beagling). Possessing a great sense of smell and superior tracking instincts, the beagle is the primary breed used as detection dogs for prohibited agricultural imports and foodstuffs in quarantine around the world. The beagle is intelligent. It is a popular pet due to its size, good temper, and a lack of inherited health problems. In rare cases, beagles may develop immune mediated polygenic arthritis (where the immune system attacks the joints) even at a young age. The symptoms can sometimes be relieved by steroid treatments. Another rare disease in the breed is neonatal cerebellar cortical degeneration. Affected puppies are slow, have lower co-ordination, fall more often and don't have a normal gait. It has an estimated carrier rate of 5% and affected rate of 0.1%. A genetic test is available.