Quality assessment of commercially available Newcastle disease vaccine in Lagos State, Nigeria

Abstract

Newcastle disease (ND) outbreaks occur among vaccinated and non-vaccinated poultry flocks causing varying degrees of economic losses despite vigorous vaccination for the control of the disease. In this study, the qualities of vaccines available for the control of ND in poultry in Lagos State were evaluated. A total of 264 blood samples were collected from poultry flocks of the enrolled farmers and 80vials of ND vaccines were obtained from nine poultry vaccine retailers patronized by the enrolled farmers. Twenty-five vials of ND vaccines were also collected from five importers that were patronized by the poultry vaccine retailers. Five vials each of the different ND vaccines were purchased from each retailers or importers and were used as representative samples of the different ND vaccines available for sale at the time of sampling. These were subjected to both physical and serological testing using Haemagglutination test (HA), Haemagglutination–inhibition test (HI) and Enzyme?linked immunosorbent assay (ELISA). Coefficient of variance of solubility among all the vaccines ranged from 7.06% to 378.89%. Vaccines obtained from retailers had meanHA titres of between 0.2 log and 11 log , while for the imported vaccines the mean HA titre 2 2 was between 6 log₂and 10.8log₂. Two hundred and sixty-four sera were tested for ND antibody, out of which 240 (90.91%) and 262 (99.24%) were positive for the presence of protective HI and ELISA ND antibodies respectively. From this study, lower coefficient of variance of solubility was observed in vaccines from importers than those from retailerswhich could indicate that vaccines are probably better stored by importers than the retailers. There should be proactive government monitoring agency at all levels of vaccine protocols.