An occurrence of Newcastle disease in pigeons: virological and serological studies on the isolates.

The antigenic and pathogenetic relationship between pigeon Newcastle disease virus (NDV) isolates during outbreaks of 1982 in Italy and reference pathogen and non-pathogen NDV-strains were investigated. The pigeon-isolates were slow-eluters and showed a thermostability at 56 degrees C of over 30 min. They proved to be lentogenic as measured by the mean-death-time in chicken-embryos, and between lentogenic and mesogenic as measured by the Hanson test. They failed to produce plaques in chicken-embryo-fibroblasts and showed high pathogenicity for experimentally infected pigeons, low-pathogenicity for quails and were not pathogenic for chickens. They were antigenically different from the LaSota strain as measured by the cross-HI-test and induced considerable seroconversion in inoculated animals. The existence of a lentogenic neurotropic pigeon-pathogenic strain was considered.