Assessment of Antibody Response to Newcastle Disease Vaccination in Chickens in Some Commercial Farms in Three Local Government Areas in Lagos State, Nigeria
Despite the rigorous vaccination programs, outbreaks of Newcastle disease (ND) are often reported in vaccinated as in unvaccinated flocks. This study evaluated antibody (Ab) response following vaccination against Newcastle disease in three Local Government Areas (LGAs) of Lagos State. A total of five hundred and twenty eight sera were collected and tested for NDV antibody using Haemagglutination- inhibition test. The three Local Government Areas (LGAs) were: Epe, Etiosa and Ojo of Lagos state, Nigeria. One hundred and three samples were negative and the mean Ab titre ranged from 2.86±2.92 to 5.19±3.00. Etiosa had a total of two hundred and forty six sera tested with forty one negative samples and a mean Ab titre of 5.19±3.00 and mode of 6 log₂. It had 25.1% of Ab titre of unprotective level at ≤3 log₂ and 74.9% of protective level at ≥4log₂. Antibody titre at protective level across the age distribution was recorded at 80.0%, 60.0% and 78.9% in Chicks, Growers and Layers respectively. The risk factors identified in Etiosa were rodent infestation 1.75, lizard infestation 2.00 and carcass disposal 1.82. A total of one hundred and twenty nine sera were tested for ND Ab in Epe with fifty seven negative samples and mean Ab titre of 5.63±2.15 and mode of 5 log₂. The number of samples with antibody titre at ≤ 3 log₂ was 15.0% and 85% sera at ≥4 log2. The age distribution of Ab titre at protective level was recorded at 76.7% in growers and 74.4% in layers while about 25.6 % in layers and 23.3% in Growers were unprotected. The risk factors identified were unmanned gate 2.10, Feed Spillage 2.10, Fly infestation 3.00, Carcass disposal 2.00 and backyard poultry 2.10. A total of one hundred and twenty two sera were tested in Ikorodu and fifty samples were negative with a mean antibody titre of 2.86±2.92. It had 54.3% antibody titre at ≥3 log2 and 45.7% at ≥4 log₂. It recorded percentage age distribution of unprotected antibody titre of 65.0 % in grower and 52.3% in layers. While 35.0% in growers and 47.7% in layers had protective antibody titre. Risk factors identified were unmanned gate 2.30, rodent infestation 2.30, lack of personal protective equipment (PPE) 2.40 and risky visitors 1.80. Conclusion, birds in Epe were better immune from Newcastle disease compared to Etiosa and Ikorodu in that order. Ikorodu recorded highest number of farms with risk factors and at risk of outbreak of Newcastle disease compared to Epe and Etiosa.