To investigate this perception that the NDV live virus vaccine could be the source of Avian Influenza A virus (H9) contamination. Sixteen samples of ND live virus vaccines were purchased from the local market. Prior to use in birds, the samples were tested for Avian Influenza A virus contamination through RT-PCR and used in live birds for any gross pathology and histopathology changes. All the samples were negative against Avian Influenza A virus. Furthermore, these vaccines were also used in broiler and desi chicks at day 5 and day 21 through eye drop and drinking water route respectively. Then, these birds were slaughtered at day 10, 20, 30 and 40 for any gross pathological and histo-pathological changes against Avian Influenza (H9). There were no macroscopic and microscopic lesions observed in visceral organs like trachea, lungs, liver and spleen for Avian Influenza. The results of the study using RT-PCR indicated that the ND live virus vaccine both (local and imported) was free of Avian Influenza A virus (H9). There was a perception among some technical persons that some Avian Influenza outbreaks in the field might be through the source of Newcastle Disease live virus vaccine. This theory regarding contamination of Avian Influenza A virus in Newcastle Disease live virus vaccines found to be wrong on the basis of this study and these commercial vaccines placed in the market are safe to use against Newcastle Disease and are not source of Avian Influenza outbreaks in the field.
Use of temperature-sensitive mutants of influenza A virus as live virus vaccine strains. Evaluation in laboratory animals, adults and children
