Comparative study on the pathogenicity and immunogenicity of wild bird isolates of avian paramyxovirus 2, 4, and 6 in chickens.

Based on the haemagglutination inhibition assay, nine antigenically distinct serotypes of avian paramyxoviruses (APMV) are described. Isolates from APMV 2, 3, 6 and 7 can cause respiratory symptoms and/or problems of the reproductive tract that may produce complications if secondary infections occur, while isolates from APMV 4, 5, 8 and 9 rarely produce clinical signs in species from which they are isolated. Isolates belonging to the APMV 1 subtype induce a wide range of disease symptoms varying from mild symptoms to a disease with devastating consequences as caused by velogenic Newcastle disease virus. In this report, one isolate each of APMV 2, 4, and 6 were isolated from wild birds and subsequently characterized in specific pathogen free chickens. All three isolates caused no clinical symptoms but showed microscopic lesions in the trachea, lungs, gut, and pancreas characteristic for a viral infection. Interestingly, only APMV 2 induced haemagglutination inhibition antibodies, while haemagglutination inhibition antibodies of chickens infected with APMV 4 and 6 were not detected. The replication of the virus in the birds was confirmed by isolation of the virus in embryonated eggs.

Prevalence of antibodies to different avian paramyxoviruses in commercial poultry in the United States.

Avian paramyxoviruses (APMVs) other than Newcastle disease virus have been isolated from feral avian species and have the potential to cause clinical disease. The objective of this study was to investigate the APMV antibody prevalence in commercial poultry settings. Sera from 100 commercial, layer-type and broiler-type (broiler-breeder and broiler) chicken flocks were analyzed on a random basis. Pooled serum samples from each flock were tested for the presence of antibodies to APMV-1, -2, -3, -4, -6, -7, -8, and -9 by hemagluttination inhibition (HI) test. Reactions with HI titers > or = 1:64 were shown by APMV-1 (71%), APMV-2 (15%), APMV-3 (35%), APMV-4 (26%), APMV-6 (45%), APMV-7 (27%), APMV-8 (31%), and APMV-9 (48%). In the presence of a high HI titer for APMV-1 (1024), we obtained positive HI titers for most of the other APMV subtypes, thus implicating that sensitive techniques need to be developed to detect the prevalence of these subtypes in commercial poultry.