Evaluation of a vaccine and a newly developed essential oil against H9N2-avian influenza

​​Samar Dankar, “Evaluation of a vaccine and a newly developed essential oil against H9N2-avian influenza”. 2006


Twenty-four poultry farms were investigated during the summer of 2004 for a first emergence of Avian Influenza (AI) outbreak in Lebanon. Commercial layers and meat breeder farms showed a significant drop in egg production greater than free-range layer farms. In addition, the HI test confirmed that most of AI-ELISA positive chicken flocks had H9 antibodies. The isolated and propagated AI virus from brains of broilers was confirmed as H9N2 subtype. Another experiment was done in October 2004; in order to evaluate an Intervet killed vaccine against H9N2 virus in poultry layers. The vaccine was administered two times in layers of a free-range farm, and three times in the commercial intensive farm. Results showed that killed H9N2 vaccine needs to be boosted 2 or 3 times in order to have a successful seroconversion.The objective of the third study is to evaluate the impact of essential oils of Eucalyptus and peppermint (Mentofin [registered trademark]) on homogeneity of immune responses to live vaccines and on performance of MG/ H9N2-infected broilers. Mentofin treatment was allowed for three days, starting at 21 days of age. The pattern of improvement of coefficient of variation (CV) value was observed for titers against Infectious Bronchitis Virus and Newcastle disease virus. Broilers of the Mentofin treatment showed better performance, less signs and lesions, better feed conversion, and lower cumulative mortality, when compared to the control untreated group. Overall, a net profit equivalent to $ 491.20 (after subtraction of Mentofin cost) was saved per 10,000 Mentofin -treated birds. Diluted Origanum ehrenberjii and syriacum essential oils were tested in vitro for their antibacterial effect and in vivo for their antiviral effect against H9N2-AI intracerebral challenge in day-old chicks. The diluted essential oils were compared in vivo to the prevalent drugs against AI-H9N2. Amantadine sulfate reduced mortality to 30 while O. syriacum reduced mortality to 60% in comparison to challenged and untreated control group (90%).

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