Transient paralysis is a form of Marek’s disease. It is rarely observed and usually not fatal. It appears 6–12 days after infection and lasts for a few days. Often misdiagnosed as Newcastle disease. Ataxia and paralysis of the wings and, particularly, of the neck and legs can be observed. Predominantly, 6-18-week-old replacement breeders are affected; they usually recover. More information on this rare condition in the chapter Marek's disease.