Seroepidemiology of Infectious Laryngotracheitis (ILT) in the Commercial Layer Farms of Chittagong District, Bangladesh

This study was carried out to determine the seroprevalence of Infectious Laryngotracheitis virus (ILTV) in commercial layer farms of Chittagong district, Bangladesh.Antigen coated indirect ELISA was performed to determine the antibody titre against ILTV.The overall seroprevalence of ILTV was 17.33% in commercial layer farms in 5 selected Upazilas of Chittagong district.The highest seroprevalence was found in Anowara upazila (26.67%) followed by Rangunia (18.46%),Raozan (16.67%),Boalkhali (13.33%) with the lowest prevalence in Patia (10.90%).The seroprevalence of ILTV was found higher in winter (24%) season compared to rainy (16%) and summer (12%).Significantly higher seroprevalence of ILTV was observed in the birds of 10-35 weeks of age (23.24%) than the birds of 36-70 weeks of age (7.83%).Prevalence of ILT was found significantly higher (P<0.05) in the farms maintaining lower biosecurity (biosecurity category 2) (22.78%) than in the farms maintaining higher biosecurity (biosecurity category 1) (9.17%) and the ILT was more predominant in the birds rearing in deep liter (23.48%) than in the cages (13.14%) which is statistically significant (P < 0.05) with χ2-value of 4.9144.These results denoted that wide seroprevalence of ILTV in commercial layer farms of Chittagong district of Bangladesh.