Molecular and retrospective analysis of pigeon paramyxovirus type 1 infections in confinement- reared pigeons (Columbia livia); 2010-2020

Pigeon paramyxovirus type 1 (PPMV-1; species Avian orthoavulavirus-1) causes a highly infectious, acute disease of Columbiformes. The objectives of this study were to estimate the occurrence of PPMV-1 in confinement-reared pigeons in California, conduct molecular char-acterization of PPMV-1 isolates from diagnostic cases, assess the presentation of the disease and identify epidemiological trends based on evaluation of pigeons cases submitted to the Cal-ifornia Animal Health and Food Safety (CAHFS) laboratory system, January 1st 2010 to December 31st 2020. From 2010 to 2020, there were 230 pigeon necropsy diagnostic acces-sions that included a total of 679 pigeons submitted to the lab. PPMV-1 was diagnosed in 23% (53/230) of accessions involving 206/679 PPMV-1 positive pigeons submitted for necropsy. PPMV-1 was diagnosed at least once per year, with the highest percentage of diagnosed cases occurring in 2014 (41.7%, 5/12). Trichomoniasis (32.1%) was the most common comorbidity in squab cases while colibacillosis (20.0%) was most commonly detected in PPMV-1 positive racing and show pigeons. The severity of lesions in PPMV-1 cases was also highly variable and pathology was most often described in the kidneys, pancreas, brain, and spleen. Phyloge-netic analysis was conducted on the matrix gene and portions of the phosphoprotein and fusion genes of 35 PPMV-1 isolates. The sequence similarities between strains ranged from 93 to 100% identity and all but one of the strains were segregated into 1 of 4 unique clades. While no temporal pattern was evident in the phylogenetic tree, there were some differences with regard to production class and geography.