Abstract
This study reports on the simultaneous administration of live NDV or aMPV subtype B vaccines alongside two live IBV (Massachusetts-H120 and 793B-CR88) vaccines in day-old maternal-antibody positive commercial broiler chicks. In the first experiment, chicks were divided into four groups; one unvaccinated and three groups vaccinated with live NDV VG/GA-Avinew, live H120 + CR88, or VG/GA-Avinew + H120 + CR88. In the second experiment, live aMPV subtype B vaccine was used in place of NDV. Clinical signs were monitored daily and oropharyngeal swabs were taken at regular intervals for vaccine virus detection. Blood was collected at 21 dpv for serology. 10 chicks from each group were challenged with virulent strains of M41 or QX or aMPV subtype B. For IBV, after 5 days post challenge (dpc), tracheal ciliary protection was assessed. For aMPV, clinical scores were recorded up to 10 dpc. For NDV, haemagglutination inhibition (HI) antibody titres were assayed as an indicator of protective immunity. In both experiments, ciliary protection for IBV vaccinated groups was maintained above 90%. The protection against virulent aMPV challenge was not compromised when aMPV, H120 and CR88 were co-administered. NDV HI mean titres in single and combined NDV-vaccinated groups remained above the protective titre (>3 log2). Both experiments demonstrated that simultaneous administration of live NDV VG/GA-Avinew or aMPV subtype B alongside H120 and CR88 vaccines does not interfere with protection conferred against NDV, IBV or aMPV.
Highlights
Newcastle disease (ND), caused by an avian paramyxovirus serotype 1 [1], and infectious bronchitis (IB) caused by an avian coronavirus [2], are known to give rise to severe diseases in chickens, with disastrous economic losses and welfare concerns [3,4]
Vaccine strains: Commercially available live Infectious bronchitis virus (IBV) Mass type strain H120 (Bioral, Boehringer Ingelheim, Lyon, France) and IBV variant 793B type strain CR88 (GallivacÒ IB88, Boehringer Ingelheim, Lyon, France), Newcastle Disease virus (NDV) VG/GA-Avinew strain (AvinewÒ NeO, Boehringer Ingelheim, Lyon, France) and avian metapneumovirus (aMPV) subtype B (NemovacÒ, Boehringer Ingelheim, Lyon, France) vaccines were administered during this study
PCR and bacterial culturing confirmed an absence of NDV, aMPV, avian influenza virus (AIV), infectious laryngotracheitis virus (ILTV), infectious bursal disease virus (IBDV), fowl adenovirus (FAdV) and mycoplasmas in all inocula [30,31,32,33,34,35]
Summary
Newcastle disease (ND), caused by an avian paramyxovirus serotype 1 ( designated as orthoavulavirus 1) [1], and infectious bronchitis (IB) caused by an avian coronavirus [2], are known to give rise to severe diseases in chickens, with disastrous economic losses and welfare concerns [3,4]. With the introduction of aMPV in 19900s, the possibility of heterologous co-vaccination of NDV + aMPV and IBV + aMPV at day-old was investigated [19,20,21,22,23] These publications showed that simultaneous administration of aMPV vaccine alongside NDV or IBV vaccine were compatible, with protection against virulent IBV, NDV or aMPV remaining uncompromised. With the increased use of co-vaccination strategies in commercial broiler chicks, it is important to understand how such vaccinecombinations may impact protection against IBV, aMPV or NDV challenges. This study reports the results of two experiments where live IBV vaccines of Massachusetts and 793B were coadministered alongside a live aMPV subtype B or live Newcastle disease vaccine in commercial broiler chicks
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