Protection in specific pathogen free chickens with live avian metapneumovirus and Newcastle disease virus vaccines applied singly or in combination

Abstract

This paper describes two experiments. In each experiment, 1-day-old specific pathogen free chicks were divided into three groups. In Experiment 1*[avian metapneumo virus (aMPV) challenge]*one group served as unvaccinated controls; the second group was vaccinated with live aMPV (subtype B) vaccine only, and the third group received the aMPV vaccine in combination with live Newcastle disease virus (NDV) vaccine (VG/GA strain). Oropharyngeal swabs, tissues and blood samples were collected before and after challenge with a virulent subtype aMPV at 21 days post vaccination. Chicks were monitored for postchallenge clinical signs. Swabs and tissues were examined for the detection of challenge aMPV by virus isolation and by reverse-transcriptase polymerase-chain reaction. Sera were assayed for antibodies against aMPV and NDV. The single and combined vaccinated chicks were all protected against clinical signs and no challenge virus was isolated from either of the vaccinated-challenged groups. In Experiment 2 (NDV challenge), as in Experiment 1, chicks were divided into three groups where one group remained as unvaccinated control and the other two groups were vaccinated as above, except that the second group received live NDV vaccine only, instead of aMPV. At 21 days post vaccination, 15 chicks from each of the three groups were removed to a different site and challenged with a virulent NDV (Texas GB strain). Reisolation of the challenge virus was not attempted. All chicks in both NDV-vaccinated challenged groups were protected against clinical signs and mortality. These results show that, based on parameters monitored for the respective challenge virus, simultaneous application of live aMPV and NDV vaccines did not affect the efficacy of either vaccine.

Comparative protective immunity provided by live vaccines of Newcastle disease virus or avian metapneumovirus when co-administered alongside classical and variant strains of infectious bronchitis virus in day-old broiler chicks

“…Challenge strains: Virulent virus strains of IBV (M41, 10 5.0 Ciliostatic Dose (CD) 50 /ml; QX, 10 6.0 CD 50 /ml) and aMPV (subtype B; 10 4.51 CD 50 /ml) were used for challenge. All challenge strains have been propagated in our laboratory and used in several previous studies [19,23,29]. 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].…”

“…Gelb et al (2007) demonstrated how NDV immunity decreased when combined with an IBV Arkansas vaccine in broiler chickens [7]. With the introduction of aMPV in 1990 0 s, 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.…”

Compromised T-cell immunity in turkeys may lead to an unpredictable avian metapneumovirus vaccine response and variable protection against challenge

“…In Experiment 3 aMPV-A was barely detectable, and in Experiment 2 its replication was delayed as compared with the rapid aMPV-A vaccine detection and clearance in the absence of aMPV-B in Experiment 1. Delayed or reduced replication of aMPV vaccines was reported after co-administration with other respiratory viruses, such as Newcastle disease virus or infectious bronchitis virus (Cook et al, 2001;Ganapathy et al, 2007;Tarpey et al, 2007).…”

“…Avian metapneumovirus (aMPV) is an important pathogen of turkeys and the causative agent of an acute disease of the upper respiratory tract, which is referred to as turkey rhinotracheitis (TRT) (Gough, 2003). TRT causes considerable losses to the turkey industry, mainly due to secondary bacterial infections (Cook et al, 1991;Van de Zande et al, 2001;Marien et al, 2005;.…”

Genetic mutations in live infectious bronchitis vaccine viruses following single or dual in vitro infection of tracheal organ cultures

“…It is known that simultaneous IBV and avian metapneumovirus (aMPV) vaccination can impair the effective replication of aMPV live vaccines in chicks (Cook et al, 2001). Working with aMPV and Newcastle disease virus interaction, Ganapathy et al (2007) reported a delayed detection of aMPV by RT-PCR. We witnessed a similar situation for the two IBV vaccine serotypes in this study.…”