Heterologous live infectious bronchitis virus vaccination in day-old commercial broiler chicks: clinical signs, ciliary health, immune responses and protection against variant infectious bronchitis viruses

Abstract

Groups of one-day-old broiler chicks were vaccinated via the oculo-nasal route with different live infectious bronchitis virus (IBV) vaccines: Massachusetts (Mass), 793B, D274 or Arkansas (Ark). Clinical signs and gross lesions were evaluated. Five chicks from each group were humanely killed at intervals and their tracheas collected for ciliary activity assessment and for the detection of CD4+, CD8+ and IgA-bearing B cells by immunohistochemistry (IHC). Blood samples were collected at intervals for the detection of anti-IBV antibodies. At 21 days post-vaccination (dpv), protection conferred by different vaccination regimes against virulent M41, QX and 793B was assessed. All vaccination programmes were able to induce high levels of CD4+, CD8+ and IgA-bearing B cells in the trachea. Significantly higher levels of CD4+ and CD8+ expression were observed in the Mass2 + 793B2-vaccinated group compared to the other groups (subscripts indicate different manufacturers). Protection studies showed that the group of chicks vaccinated with Mass2 + 793B2 produced 92% ciliary protection against QX challenge; compared to 53%, 68% and 73% ciliary protection against the same challenge virus by Mass1 + D274, Mass1 + 793B1 and Mass3 + Ark, respectively. All vaccination programmes produced more than 85% ciliary protection against M41 and 793B challenges. It appears that the variable levels of protection provided by different heterologous live IBV vaccinations are dependent on the levels of local tracheal immunity induced by the respective vaccine combination. The Mass2 + 793B2 group showed the worst clinical signs, higher mortality and severe lesions following vaccination, but had the highest tracheal immune responses and demonstrated the best protection against all three challenge viruses.

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

“…Ciliostasis results in the current study highlighted excellent IBV protection against M41 and QX challenges in groups receiving H120 + 793B, or the same IBV vaccines given along with aMPV or NDV vaccines. Previous work has shown that the combination of Mass + 793B conferred excellent ciliary protection against Asian (QX and Q1) and Middle East (IS/1494/06 and IS/885/00) IBV strains [25,[48][49][50][51]. When IBV H120 and CR88 Table 5 Experiment 2: IBV or aMPV detections from trachea and kidney samples at 5 days post M41 or virulent aMPV challenge.…”

Genetic diversity of avian infectious bronchitis virus in China in recent years

“…In some cases, the IBV vaccine can induce mild signs (such as nasal discharge) of IB shortly after administration (Matthijs et al, 2003(Matthijs et al, , 2005(Matthijs et al, , 2008, and increases the susceptibility of 4-week-old broilers to colibacillosis to a similar extent as the virulent IBV strain (Matthijs et al, 2005). In addition, the variable virulence of the vaccine viruses when they are coadministered and the ability of some of the combinations to cause severe tracheal damage have been reported (Awad et al, 2016). Most of the diseased broilers in which IBV vaccine-like viruses were isolated in this study showed mild to severe colibacillosis when they were approximately 4 weeks old.…”

Genotyping of avian infectious bronchitis virus in Iran: Detection of D274 and changing in the genotypes rate

“…IS/1494/06 challenge [33]. Awad et al showed that one-day-old chicks vaccinated with two different mixtures of Mass + 793/B produced 92% and 68% ciliary protection against QX challenge [11]. Mohammadi et al showed a protective ability of the used vaccination program.…”

“…Among a large number of serotypes or variants emerged after the first documentation of IBV in 1931, Massachusetts 41 (M41) and 793/B serotypes have been expanded through the world and commercial vaccines are available against both serotypes providing a broad crossprotection against many different IBV types when used together [7][8][9]. Despite vaccination efforts, novel field IBVs continue to emerge; some antigenic variants may subsequently become dominant which makes prevention of IBV infections very challenging [10,11]. Similar to what has been happening in Iranian poultry farms leading to unceasing IB outbreaks despite extensive vaccination.…”