engleski

Oil emulsion of split Newcastle disease virus as an ecologically safe vaccine

Newcastle disease is a worldwide spread poultry disease that cause great financial losses. For this reason poultry industry is greatly dependent upon vaccination to control the disease. One of the negative effects accompanying vaccination is possible uncontrolled virus replication. For this reason we prepared an ecologically safe split vaccine against Newcastle disease virus (NDV). The protective value of this vaccine in light laying chickens and chickens hatched from SPF-eggs, was determined. The split vaccine was prepared by virus inactivation with formaldehyde, followed by controlled virus solubilization with non-ionic detergent Tween 80. As a result, the subunits, free of infectivity, but of an appropriate mass to elicit efficient immune response, were obtained. The detergent was not removed from the viral preparation after accomplishing solubilization. The vaccine was prepared in the form of a water-in-oil-in-water emulsion (WOWE) with a low content of a light mineral oil and Tween 80 as aqueous-phase emulsifier. In order to determine the protective dose according to the Eu.Ph, a volume of 0.2 ml of the NDV split vaccine was intramuscularly (i.m.) administered to 21-day-old light laying (one dose, equivalent of 1/5, 1/25 and 1/50 of a dose) and chickens hatched from SPF-eggs (equivalent of 1/10, 1/25, 1/50 and 1/100 of a dose). Challenge was carried out 3 weeks after vaccination by i.m. injection of 106 ELD50 of Herts 33 strain of NDV. Using the Spaerman-Kärber method it was determined ł100 PD50 per ml of the vaccine in both experiments.

chickens; layers; Newcastle disease; water-in-oil-in-water emulsion; split vaccine

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