Preparation of Turkey Pox Vaccine in SPF Eggs
2018
Olfat E. Nakhla | Manal Awad | Soad M. Soliman | A. Michael
An identified local virulent Egyptian strain of turkey pox virus (TPV) was attenuated on specific pathogen free (SPF) embryonated chicken eggs (ECE) for production of specific turkey pox vaccine. Forty serial passages of the virus were applied on the chorioallantoic membrane (CAM) of SPF ECE, so titration of the serial passages were undergone in which the highest titres (107.0, 107.1 and 107.1 EID50/ml) were recorded for the passages 30, 35 and 40, respectively. The pathogenicity of the 10th, 20th, 30th and 40th passages were tested by inoculation in susceptible turkeys. The passage of 30th and 40th passages produced the most acceptable post vaccinal reaction (pvr) beside giving the highest virus titre of the attenuated passages. The selected field dose which gave only takes (swelling of the skin) at the site of injection in susceptible turkeys and withstood challenge with the virulent turkey pox virus one month later was 104.0 EID50/ml. The prepared vaccine tested for sterility, safety and potency tests and proved to be potent for the vaccinated turkeys which resisted the challenge for 9 months post vaccination. Antibody levels in the serum of vaccinated turkeys were estimated by serum neutralization test, where neutralizing antibodies expressed as neutralizing index were appeared from the 1st week (1.0 NI) and reached its peak on the 3rd week (2.2 NI) post vaccination
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