Incidence of Avian Nephrosis in Japan With Special Reference to Isolation and Transmission Test of Infective Agents

The incidence of infectious nephrosis in young cJticks was first observed in Japan.The first clinical sign of this disease was a whitish or watery diarrhea, with vent featherssoiled by urinary unaterial. This was followed by anorexia, depression, trembling, pros-tration, and deatlt. Few or no respiratory signs were noted. Macroscopic lesions revealedmarked nephrotic changes in the kidney with the ureter swollen by heavy deposits ofuric acid.Infective agents were isolated from kidney lesions caused by inoculatior? with theallanotic fluid of infected embryonating eggs. Of them, one designated GN-2, wheninoculated intraocularly into susceptible one-day-old chicks, produced such typical kidneyIesions as found in field cases of nephrosis. When exposed to the infection by contactwith chickens inoculated with Late GN-2 isolate, one-day-old chicks presented similarclinical signs and Iesions. Fatality was higher in one-day-old chicks than 4- to 10-week-oldchicks. That agent was recovered from the kidney lesions of chicks which died.The allantoic flvuid harvested from second-passage eggs passed through rmilliporefilter GS (220 mp). The resulting filtrate caused similar lesions in one-day-old chicks.The Iesions evoked by agent GN-2 in embryor?ating eggs were dwarfing and curlingof the embryo and increased in severity with the advance in passage. Identification andcharacteristics in tissue culture of this agent will be mentioned in a paper to be publishedin the next number of this jotzrnal.