| 摘要 |
The invention relates to a process for the preparation of the lyophilized vaccine against duck hepatitis by using the attenuated hepatitis virus TN cultivated by Asplin. According to the invention the virus deposited in the Strain Collection of the Hungarian Institute of Public Healts under No. 00220 is injected into the allantoic cavity of embryonated SPF-hen's eggs, the eggs are incubated at a temperature of about 37 DEG C., the embryos died between 24 and 96 hours are collected, homogenized with a physiological saline solution, antibiotics are added to the pure suspension, and after the addition of protective and skeleton forming agents the sterile virus material is lyophilized in a manner known per se. The lyophilized vaccine can be stored at a temperature of +4 DEG C. for one year in contradiction to the known liquid vaccine storable in freezed state at a temperature of -20 DEG C. for half a year and which has to be used within 7 days from the delivery (with a storage temperature of +4 DEG C.). The titre of the vaccine prepared according to the invention is at least tenfold of that of the known vaccine, thus much less embryonated eggs are used for the process according to the invention what means cost saving. Due to the lyophilization the vaccine can be transported to far destinations, too, what was not possible at the known liquid product stored in freezed state.
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