Comparative Study of Serologic Results Obtained by HI Test of Avian Influenza and Newcastle Disease Performed in Four Mexican Laboratories

Abstract

Abstract:In the poultry industry, it is common to evaluate the humoral immune response associated to the vaccination calendar used for the different zootechnical purposes. When the vaccine against avian influenza and Newcastle disease currently used in a farm is going to be changed, an important parameter observed to choose a product over the others is based on the antibody titers reached by the application of the new vaccine. This study aimed to compare the serologic results obtained by hemagglutination inhibition (HI) test of avian influenza and Newcastle disease reported in four different national laboratories. One-day-old Ross broiler chickens were kept in Horsfall-Bauer isolation units and were vaccinated subcutaneously for the prevention of avian influenza and Newcastle disease. Then, serum of all the birds was extracted at three, six and seven weeks old and sent to four different national diagnostic laboratories, where HI test was performed for avian influenza and Newcastle disease. The treatments were designed in 4 × 3 factorial. Data showed significant statistical differences between laboratory results (up to six logarithms for influenza at six and seven weeks). This study confirms that the results of the HI test can vary from one laboratory to another, thus it is important to consider this, when the vaccines against avian influenza and Newcastle disease are evaluated at field.