SEROLOGICAL SURVEY OF SALMONELLA INFECTION IN NON-VACCINATED COMMERCIAL LAYER BIRDS IN KHULNA DISTRICT OF BANGLADESH
Keywords:Seroprevalence, Salmonella infection, serum plate agglutination (SPA), layer birds
A cross sectional study was conducted on 164120 non-vaccinated layer birds of 96 farms in six upazilas (Sadar, Batiaghata, Dumuria, Dighulia, Rupsha and Fultala) of Khulna district to determine the seroprevalence of Salmonella infection (S. pullorum and S. gallinarum) during the period from August 2009 to July 2010. Sera samples were collected from 1268 layer birds of different ages and the birds were selected through a disproportionate stratified random sampling technique based on the flock size of each farm. Sera samples were tested by Serum plate agglutination (SPA) test applying commercial Salmonella antigen (Nobilis® SA, Intervet International B.V. Boxmeer- Holland) to detect the presence of antibodies against Salmonella. The overall seroprevalence of Salmonella infection was recorded as 65.9%. The significantly higher seroprevalence (76.6%) of Salmonella infection was recorded in layer birds of >56 weeks of age than those of other age groups. Seasons had significant influence on the seroprevalence of Salmonella infection. The seroprevalence was significantly higher in summer (82%) than that in rainy (66.8%) and winter (50%) seasons. The location of farms, i.e. upazilas also had significant association with the occurrence of Salmonella infection. The seroprevalence significantly differed between the different categories of flock size. The flock size of 5001 and above had the highest seroprevalence (81.4%) among other categories. It may be concluded that above 60% layer birds in 92 out of 96 farms are infected with Salmonella organism, which requires keeping of vigilant eye of the poultry farmers and the hatchery owners in the control of Salmonella infection in poultry farms.
Bangl. J. Vet. Med. (2011). 9(1): 27-31