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.

Automated summary

This study evaluated the occurrence of PPMV-1 in confinement-reared pigeons in California, characterized PPMV-1 isolates from diagnostic cases, assessed the disease presentation, and identified epidemiological trends based on pigeon cases submitted to the CAHFS laboratory system. PPMV-1 was diagnosed in 23% of the accessions, with the highest percentage of cases occurring in 2014. Trichomoniasis and colibacillosis were the most common comorbidities in squab and racing/show pigeons, respectively. Phylogenetic analysis revealed sequence similarities and unique clades among the PPMV-1 isolates.