Abstract:

【Objective】 To understand the dynamics of viremia, virus shedding and antibody responses in chickens inoculated with avian leukosis vrius subgroup J (ALV-J) and provide essential epidemiological data for prevention and eradicationo of ALV-J infection. 【Method】 Viremia, virus shedding and antibody response were successively measured after inoculation with ALV-J strain HN0001 intraperitoneally ,orally or in contact in SPF chickens at 1 day and 49 days. 【Result】 The dynamics of viremia and antiboty responses were very different in chickens inoculated with ALV-J at different ages. Viremia and p27 in cloaca swabs started to be detected from the 2nd week after inoculation with ALV-J at 1-day-old . In the group inoculated intraperitoneally with ALV-J, 71% (5/7) continuously demonstrated viremia and p27-shedding. Viremia and virus shedding lasted for at least 45 weeks in 3 chickens. Among them, only 1 chicken showed transient antibody reaction at 16-week-old, another 2 were in tolerant viremia without any antibody reactions. In the group inoculated orally with ALV-J, 11% (1/9) demonstrated persistant viremia and p27-shedding but no antibody response, 44% (4/9) showed transient viremia or p27-shedding, and then antibody responses from 8-week-old. No control bird kept in contact with inoculated birds in the same isolators demonstrated viremia or p27-shedding, and also no antibody responses. It indicated there was no horizontal infection. In chickens intraperitoneally inoculated with ALV-J at 49-day-old , neither viremia nor p27-shedding were detected in 5 separate testing during the 19th week after inoculation, but antibody reaction started to be detected 1 week after inoculation. In the orally inoculated chickens or the contacted control chicken, all samples were negative in vriremia, p27-shedding and antibody reactions. 【Conclusion】 Inoculation with ALV-J at 1-day-old easily induced immune tolerence, chickens inoculated demonstrated persistant viremia or p27-shedding, but no antibody reactions. Chickens inoculated with ALV-J at 49-day-old, antibody could detected 1 week after inoculation, but no viremia and p27-shedding were detected. Inoculation routes significantly influenced the dynamic variety of ALV-J inoculation, intraperitoneally injection induced higher viremia levels and increased percentages with tolerant viremia when compared to oral inoculation.

Key words: avian leukosis virus of subgroup J (ALV-J), antigen p27, viremia, antibody