Protection Conferred by a Live Avian Metapneumovirus Vaccine when Co-Administered with Live La Sota Newcastle Disease Vaccine in Chicks

Abstract

This paper examines the effects on specific pathogen-free (SPF) chicks when avian metapneumovirus (aMPV) and Newcastle disease virus (NDV) La Sota strain vaccines are co-administered. Day-old SPF chicks were divided into five groups. The first group was inoculated with sterile water (SW) and the rest of the groups were inoculated with live NDV vaccine VG/GA by the oculo-oral route. At 21 days-old, the unvaccinated chicks were again inoculated with SW. The four VG/GA-vaccinated groups were further inoculated with (i) SW, (ii) live aMPV vaccine, (iii) live NDV La Sota, or (iv) combined live NDV La Sota and live aMPV, respectively. Chicks were monitored for post-vaccination reactions and oropharyngeal swabs were collected for vaccines detection. Blood samples were collected to detect aMPV ELISA and NDV haemagglutination-inhibition antibodies. Twenty-one days following the second vaccination, six chicks from each group were challenged with virulent NDV or aMPV respectively. Chicks were monitored for clinical signs and mortality and oropharyngeal swabs collected for aMPV detection. Results showed that, when challenged with a virulent aMPV, both chicks previously vaccinated with VG/GA and subsequently given aMPV vaccine singly or in combination with La Sota were equally protected against clinical signs. Chicks that were vaccinated against NDV either once with VG/GA or followed by La Sota (singly or in combination with aMPV) were fully protected when challenged with velogenic NDV. We concluded that simultaneous administration of live aMPV and NDV La Sota vaccines have no adverse effects on protection conferred by either live 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

“…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.…”

Serological and Molecular Characterization of Avian Metapneumovirus in Chickens in Northern Vietnam

“…Furthermore, to enhance the likelihood of detecting aMPV, farms were narrowed down to those with respiratory problems. Due to the relatively short viral shedding time [25,26], respiratory swabs or respiratory organs were collected from chickens showing mild to severe clinical signs from each farm. For blood collection, chickens less than three weeks old were excluded owing to the potential for maternal-derived aMPV-specific antibodies [27].…”

“…The detection rates of aMPV in northern Vietnam (17.2%) demonstrated a similar low prevalence to other countries. Three main possibilities for the low aMPV detection rates were: (i) aMPV poorly replicated in the respiratory tract of chickens compared to turkeys [45,46], (ii) relatively short viral shedding time (within one week post-infection) [25,26], and (iii) low level of viral shedding (the highest was about 10 2.7 TCID 50 /mL) [25]. Additionally, the sensitivity of the RT-PCR assay was known to affect the virus-detection results.…”

“…Additionally, the sensitivity of the RT-PCR assay was known to affect the virus-detection results. For example, nested RT-PCR enabled the finding of aMPV in chickens 28 days post-infection [47]; meanwhile, RT-PCR could generally only detect the virus within a week post-infection [10,25,26].…”

Potentiating effect of pidotimod on immune responses of chickens to live attenuated Newcastle disease vaccines

“…Newcastle disease (ND) is a widespread, highly contagious viral disease, and causes severe economic losses to poultry industry (Ahmed et al 2007;Miller et al 2010;Ganapathy et al 2014). Over the past decades, intensive vaccination programmes against ND have been practised widely (Xiao et al 2009).…”