Development of Inactivated Newcastle Disease Vaccine in Sudan

Using I-2 and La-Sota strains two inactivated Newcastle Disease (ND) vaccines were produced. The vaccine viruses were inactivated by treatment with 0.05% laboratory grade formaldehyde,then each inactivated vaccine prepared as a water in oil (W/O) emulsion. For each emulsion, the aqueous phase ratio was (2.4 : 1) (allantoic fluid : tween 80 ) respectively. While the oil phase contains (9: 1) (paraffin oil : manidmonoleate (span 80)) as an oil emulsifier. The prepared vaccines were subjected to physical tests including stability, viscosity and quality of emulsification completeness . The two vaccines were confirmed to be sterile, stable for 30 days at 37⁰ C and for 6 months at 4c^o. the viscosity was 4ml/ 8 second. Tests for safety,immunogenicity, and efficacy (challenge test) as well as cross protection evidence for the two vaccines were performed in -one day- old broiler chicks. For phase I trial the vaccines were found to be safe, immunogenic ,and effective with 80% and 40% protection level for oil emulsion vaccines derived from ND I-2 and ND La-Sota strains respectively. Because of relatively higher efficacy( 80%) obtained From I-2 strain in phase I trial, this result validate further investigation for I-2 strain in phase II clinical trial.

In phase II trial , the protection reached 93% in a group vaccinated only with inactivated ND I-2 vaccine, compared with 100% protection against very virulent ND for the group vaccinated simultaneously with live and inactivated ND I-2 vaccines. Independent sample t.test was used to compare the GMT Abs titer for the post vaccination sera with statistically insignificant outcome (P>.05). The results obtained in this study confirmed that, the killed ND I-2 vaccine produced locally was safe and efficient, and could be used with high efficiency against the very virulent ND strains , and has the potential to replace the imported ND oil vaccines.

Author(s): Manan A AA1, Kheir M.A.S1, Ballal A1 ,Nour TAM1, Fatima AT1

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