Evaluation on disease prevention ability of Navet-Fluvac 2 vaccine against A/H5N1, clade 2.3.2.1C Avian influeanza Virus in domestic mallards

Abstract

The objective of this study aimed at evaluating the safety and effectiveness of Navet-Fluvac 2 vaccine in preventing avian influeanza caused by A/H5N1, clade 2.3.2.1C virus in the domestic mallards. The studied results indicated that the vaccinated mallards with single dose (0.5 ml/head) and with double dose (1 ml/head) were healthy and eating normally. There was no manifestation of abnormality at the vaccine injection sites, and clinical signs in the vaccinated mallards. There was a difference in the level of antibody response in animals between the vaccinated mallards with one injection and two injections. For one injection, only 15.0 % of the vaccinated mallards having antibody response were detected (by using the HI test), meanwhile 93.3% (28/30) of the vaccinated mallards with two vaccinations presenting antibody response were found. 
The effectiveness of Navet-Fluvac 2 vaccine was evaluated by challenge test with H5N1 clade 2.3.2.1C avian influenza virus. The tested results showed that there were 80.0% and 93.3% of the vaccinated mallards with one and two vaccinations protected, respectively. The mortality rate of the
mallards in the control groups was ≥80.0%. This was the first report in evaluation on the effectiveness for Navet-Fluvac 2 vaccine against A/H5N1, clade 2.3.2.1C avian influenza virus in the domestic mallards in Viet Nam.