Evaluation of inactivated vaccine of the variant 2 (IS-1494 /GI-23) genotype of avian infectious bronchitis

Abstract

The infectious bronchitis virus (IBV) is the cause of avian infectious bronchitis (IB). IB is one of the most highly contagious diseases, which results in many economic losses in the poultry industry worldwide. The nature of this virus is such that it generates new genotypes continuously. Proper vaccination is the most suitable way of combatting IB. One of the novel genotypes of IBV, which has been circulating in the Middle Eastern countries, is the variant 2 (IS-1494/GI-23) genotype. This study aims to design and produce an autogenous variant 2 vaccines. After isolation and characterization of the Iranian variant 2, the inactivated vaccine was formulated according to the OIE guidelines, and its different aspects (Purity, titration, inactivation, immunization) were evaluated. The designed vaccine passed all of OIE quality control standards. In the assessment process, the protection rate in the groups receiving the variant 2 and commercial vaccines was 67 % and 60 %, respectively. Although the differences were not significant, they indicated better protection, and the viral load in the feces and the kidney of the group receiving the variant 2 vaccine was lower than that in the commercial vaccine. It is suggested that the variant2 strain should be added as one of the local strains to the commercial inactivated vaccines in areas affected by this genotype. The use of this vaccine in layer and breeder flocks can help to protect them against variant 2 during the production phase. Also, the transfer of maternal antibodies to offspring can provide strain-specific immunity for one-day-old chickens.

The emergence, evolution and spread of infectious bronchitis virus genotype GI-23

“…NT, not tested; NI, not indicated in the study 4 suggest that the best protection against an IBV challenge can be achieved using a homologous vaccine strain. This has been confirmed with Chinese QX-like IBV strains [104,105], several Korean nephropathogenic IBV strains [106], and more recently, with GI-23 strains as either live or inactivated vaccines [107][108][109][110]. Few studies have followed the international regulations, and there is a lack of standardized methodology (e.g., virus isolation versus virus molecular detection and/or quantification).…”

Molecular characterization of isolated infectious bronchitis viruses from affected vaccinated broiler flocks in Syria

“…Although, there is no commercially available vaccine against Variant-2 strains. Local trial vaccines were recently developed and evaluated in Egypt and Iran with promising results [31,32].…”

Protection of laying chickens against the Canadian DMV/1639 infectious bronchitis virus infection through priming with heterologous live vaccine and boosting with heterologous or homologous inactivated vaccine

“…Moreover, quality control measures were assessed as recommended by the oil-emulsion manufacturer. Each dose of the vaccine (0.5 ml) was adjusted to 1 × 10 6 EID 50 ( Erfanmanesh et al., 2020 ; Al-Ebshahy et al., 2019 ).…”