University of Khartoum

Development of an Inactivated Vaccine against Infectious Bursal Disease Virus

Development of an Inactivated Vaccine against Infectious Bursal Disease Virus

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Title: Development of an Inactivated Vaccine against Infectious Bursal Disease Virus
Author: Mohamed, Luai
Abstract: In the present study an inactivated IBD vaccine were developed from a local field isolate of the virus.It is anticipated that the field virus would induce better immune response in vaccinated birds due to its close antigenic relation ship. A field outbreak of the disease that occurred in 2006 in Khartoum state (Shambat) was investigated that caused 70% mortality evenin vaccinated bird. IBDV was detected by AGID test, isolation in cell culture (CEF) and reproduction of the disease in experimental chicks. The virus was isolated in CEF cell culture and identified serologically by AGDT. The virus was designed Shambat/06 and further propagated for two passages in cell culture and the TCID50was determined. Then the CEF cell culture harvest was inactivated using formalin and the viruse inactivation was tested used experimental chicks. A total of 140 layer chicks were used to determine the efficancy and safety of the developed vaccine and to compare it with commercial IBDV vaccines D78, Bur706. The results showedthat when the bursa suspension was inoculated onto chick embryo fibroblast cell culture it induce clear cytopathic effects after 5 days of inoculation. Clinical signs observed after experimental infection of susceptible chicks were similar to the classical IBD clinical signs and were characterized by sudden onset of depression, dullness, ruffled featherand death. Tissues collected from experimental chickens wereexamined histopathologically. Bursal of fabricius showed hemorrhage in the connective tissues and xi the dissociated follicular cells beside edema in the follicle and degeneration of follicles. A volume of100 ml of the inactivated virus was mixed with Aluminum hydroxideas adjuvant. Experimental chicks were vaccinated by the inactivated vaccine and for comparison additional chicks were vaccinated with D78and Bur706 commercial IBD vaccines. No signs or lesions of IBD were seen and vaccinated chicks remained healthy throughout the experiment, which means that the IBDV in the vaccine was completely inactivated by the formalin. Two preparations were made for the vaccine, with and without Aluminum hydroxide adjuvant and two routes of vaccination; intramuscular (I/M) and subcutaneous (S/C) were tried. The best result in terms of immune response and withstanding challenge was obtained when the adjuvanted inactivated vaccine was given by the intramuscular route. Results showedalso that the developed vaccine without adjuvant when given by I/M gave a relatively lower protective immune response of 73.3%comparing with 93.3% for the adjuvanted vaccine which mean that the absent of the adjuvant make loss of 20% at immune response. The results also revealed comparable protective immune response between D78, Bur706 vaccines and the developed adjuvanted vaccine when the latter was given by I/M route. On the other hand, the developed vaccinewithout adjuvant showed 20% lower protective immune response compared with the commercial vaccines. The results also showed similler withstanding challenge for both shambat/06/adj and D78 while Bur706 was slightly better than both above vaccines. The higher uniformed higher titer from 8,000 xii upto 12,000 was induced in vaccinated chicks by the developed vaccine with adjuvant when given by I/M. The efficacy of the developed vaccine observed in the present study is promising and indicate that the developed vaccine may became a good alternative method to control IBD in Sudan
URI: http://khartoumspace.uofk.edu/handle/123456789/8995
Date: 2015-04-15


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