Determination of antibody level protecting against Derzsy's disease in day-old and 8-day-old SPF goslings
1998
Kelemen, M. | Nagy, J. | Erdei, J. (Phylaxia-Sanofi Oltoanyag-termelo Rt., Budapest (Hungary))
Since information in bibliography is insufficient and it is based mainly on epidemiologic observation, the aim of this study is to determine in the blood of day-old goslings as well as in Derzsy's disease antiserum the VN titers which afford full protection. Each of SPF goslings allotted into three groups was given 2 ml antiserum subcutaneously within 4 hours after hatching. Titer of the antiserum given to group 1 amounted to 1:750, those for group 2 and group 3 were 1:500 and 1:250, respectively. VN titers of blood samples were determined 24 hours post inoculationem and weekly for 4 weeks. Each of the groups were divided in two and challenge-infected with 0.5 ml of virulent virus Derzsy B (the challenge dose contained 478.6 LD50 for day old goslings and 213.8 LD50 respectively for 8-day-old goslings) by the intraperitoneal route on day 1 and day 8. Birds injected with so-called negative serum (VN titer 2) which were challenged as well as uninjected and unchallenged birds served as controls. It has been found that in the blood of goslings VN titer of 1:34 at day old or a VN titer of over 1:24 at 8 days old were safe, however a titer under 1:16 afforded partial protection against a challenge-infection with virulent virus. These protective titers were found in goslings after the treatment with 1:500 titered serum and particularly with 1:750 titered serum. The VN titer of 1:52 at day old afforded by a treatment with an antiserum of VN titer 1:750 which complies with specification proved to be safely sufficient for protecting birds from clinical signs of Derzsy's disease
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