Studies On Avirulent Vaccine Of NDV Strain B₉₅ And On Detection Of NDV Strain B₉₅ By RT-PCR

Comparing to the effect of culture in Vero cell, the allantoic cavity route was selected to cultivate the NDV strain B95. Through inspecting the allantoic fluid, no evidence for non-safety and contamination was found. EID50 of the fluid was up to 107.75. The fluid could be accepted as the vaccine. In the experiment, the minimum dose of vaccination with strain B95 was detected as 105.75 EID50 by intraocular-nasal route and as 106.75 EID50 by feed-based route. The experiment on the effect of the vaccine showed that the chickens vaccinated with strain B95 through intraocular-nasal route can survive the challenge of virulent virus at fifth day after vaccination and the duration of immunity was four months. The experiment showed the chickens in contact with those vaccinated with strain B95 could be protected from the challenge and the difference on the percentage of protection was non-significant in comparison to the group vaccinated with strain B95. The result of feed-based vaccination showed the percentage of protection from challenge was 66.7%. the difference was also non-significant in comparison to the group vaccinated with strain B95 through intraocular-nasal route. The experiment on duration of storage of the vaccine result showed it could store two months under the environmental temperature and store four months under 0～4℃ without affecting the efficacy of it.In the experiment of RT-PCR detection for NDV strain B95, the result showed that it had the specific to strain B95 and the sensitivity is 0.0043ng/ul.