Location: Exotic & Emerging Avian Viral Diseases Research
Project Number: 6040-32000-082-010-I
Project Type: Interagency Reimbursable Agreement
Start Date: Mar 1, 2026
End Date: Feb 28, 2030
Objective:
To develop Avian metapneumovirus (AMPV) vaccines and vaccination strategy that are readily applicable to U.S. poultry.
Approach:
Avian metapneumovirus (AMPV) subtypes A and B have recently been detected for the first time in the U.S. and continue to spread and impact all the poultry sectors (broilers, layers, layer and broiler breeders, and turkeys). Vaccination is one of the most effective control measures and has been used in other countries, but no AMPV vaccine is available in the U.S.
Cell-mediated immunity, as well as antibody response, is critical in controlling AMPV infection and transmission. For this reason, live attenuated vaccines, which can induce both cellular and humoral immune responses, have been developed through serial passaging of AMPV field isolates in cell culture. However, the current procedure of attenuating field isolate is tedious and time-consuming with no prior knowledge which passage level will generate attenuated virus that is still immunogenic and safe to use. The safety and stability of live vaccines continue to be a concern and several AMPV outbreaks were found to be due to the reversion of the vaccine virus to a pathogenic form.
ARS researchers will develop live virus-vectored vaccines expressing two major AMPV antigens, fusion (F) and glycoprotein (G), and immunostimulatory genes utilizing safe and stable avian paramyxovirus type 1 (APMV-1) virus vector and herpesvirus vector developed at the Southeast Poultry Research Laboratory. AMPV and immunostimulatory genes will be de novo synthesized commercially and incorporated into the APMV-1 and herpesvirus vectors. The expression of the AMPV F and G protein in infected cells will be examined using an immunofluorescence assay. In addition, replication dynamics and pathogenicity of the recombinant virus will be determined using standard methods. Once the adequate growth and safety profile of the candidate vaccine viruses are confirmed, immunization and challenge experiments will be done with selected vaccine candidates in chickens and turkeys to evaluate the cross protective immunity (both humoral and cellular immune responses) and efficacy (ability to reduce clinical signs and virus shedding).