A Filterable Virus, Distinct from that of Laryngotracheitis, the Cause of a Respiratory Disease of Chicks

A RESPIRATORY disease of chicks clinically similar to infectious laryngotracheitis was reported upon by Schalk and Hawn (1931) under the title “An apparently new respiratory disease of chicks.” They stated that the disease was confined to chicks from 2 days to 3 weeks of age, the first cases appearing, in most instances, on the fifth to ninth day after removal from the incubator. The symptoms described were gasping, listlessness, and depression. Constant post-mortem findings were said to be acute congestion of all or a portion of one or both lungs and seromucoid liquid exudate in the bronchi and bronchioles. Mucous exudate was found in the nasal passages of a considerable number of the affected chicks. An outbreak ran a rapid course of 3 to 6 days’ duration, from 25 to 75 percent of the chicks became diseased, and from 40 to 90 percent of infected chicks succumbed. The disease was . . .