Duration of immunity following the administration of oil-based avian influenza H_5N_1 vaccine in layers


Abstract: Avian influenza (AI) occurs worldwide and causes tremendous economic losses. The disease is characterised by respiratory signs, depression, and reduced food and water intake. In the present study, an oil-based vaccine created by using Montanide ISA 70 MVG, was prepared and the duration of immunity checked at different time intervals. For this purpose, the cumulative mean titre (CMT) was calculated after employing haemagglutination inhibition test in 50 pullets at day zero before vaccination and then inoculated 0.3 mL of emulsified vaccine subcutaneously in 40 birds while 10 birds were kept non-vaccinated as a control group throughout the experiment. On day 21, a booster dose of 0.5 mL emulsified AI vaccine was injected into the vaccinated birds that produced highest CMT at day 63 and maintained the protective antibody titre on day 84, 105, 126, 152, 182, and 228 in layers. The study showed that a booster dose at day 21 produced a high protective AI antibody titre in birds that minimises the stress of repeated shots of aqueous vaccine.

Keywords: Avian influenza, Montanide ISA 70 MVG, cumulative mean titre, haemagglutination inhibition test, layer

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