Genetic and Antigenic Characterization of Avian Avulavirus Type 6 (AAvV-6) Circulating in Canadian Wild Birds (2005–2017)

Abstract

We describe for the first time the genetic and antigenic characterization of 18 avian avulavirus type-6 viruses (AAvV-6) that were isolated from wild waterfowl in the Americas over the span of 12 years. Only one of the AAvV-6 viruses isolated failed to hemagglutinate chicken red blood cells. We were able to obtain full genome sequences of 16 and 2 fusion gene sequences from the remaining 2 isolates. This is more than double the number of full genome sequences available at the NCBI database. These AAvV-6 viruses phylogenetically grouped into the 2 existing AAvV-6 genotype subgroups indicating the existence of an intercontinental epidemiological link with other AAvV-6 viruses isolated from migratory waterfowl from different Eurasian countries. Antigenic maps made using HI assay data for these isolates showed that the two genetic groups were also antigenically distinct. An isolate representing each genotype was inoculated in specific pathogen free (SPF) chickens, however, no clinical symptoms were observed. A duplex fusion gene based real-time assay for the detection and genotyping of AAvV-6 to genotype 1 and 2 was developed. Using the developed assay, the viral shedding pattern in the infected chickens was examined. The chickens infected with both genotypes were able to shed the virus orally for about a week, however, no significant cloacal shedding was detected in chickens of both groups. Chickens in both groups developed detectable levels of anti-hemagglutinin antibodies 7 days after infection.

Putative novel avian paramyxoviruses identified from wild bird surveillance (United States, 2016‒2018) and retrospective analysis of APMV-2s and APMV-6s in GenBank

“…The classification of APMVs within a sample has historically relied on serological methods, primarily HI assays, by using anti-sera of known APMV isolates (13,25,37). Although this method has differentiated species that are distantly related, cross-reactivity between some APMV serotypes have been identified and accurate species classification may be problematic due to the rapidly increasing identification of novel paramyxovirus species and the difficulty that creates in terms of laboratories having access to anti-sera for the ever increasing number of APMV species (25).…”

“…Due to an increase in surveillance studies in the early 2000's, APMV-10 to -22 have been detected across the globe in various wild bird species, including penguins and migratory shorebirds and waterfowl (2,(9)(10)(11). Furthermore, the accessibility of next-generation and third-generation sequencing have contributed to a better understanding of the molecular characterization and genetic diversity of APMVs in wild birds (2,12,13).…”

“…While recent advances in sequencing technology have enhanced the characterization of APMVs, there is still a paucity of public sequence data available for APMV-2 to -22 due to historical studies relying on serotyping methods for identifying species (3,5,13). For example, GenBank currently contains less than 160 complete genomes for APMV-2 to -22, whereas there are over 1,200 complete genomes for APMV-1 alone (accessed on 13 Aug 2021).…”

“…Additionally, the P gene contains an mRNA editing site in which one or two G residues are inserted to produce a V and W protein, respectively (14). By sequencing the HN gene or the F gene, the genetic diversity has been studied in a several non-APMV-1 species: APMV-2 (15,16), APMV-3 (17), APMV-4 (18)(19)(20)(21)(22), and APMV-6 (13,23,24), and can be used for predicting antigenicity (13,25). With the exception of sequencing complete genomes of newly described species, even fewer studies have sequenced the L gene from APMVs, which is currently the gene used by ICTV-recommended methods to speciate paramyxoviruses.…”

“…With the exception of sequencing complete genomes of newly described species, even fewer studies have sequenced the L gene from APMVs, which is currently the gene used by ICTV-recommended methods to speciate paramyxoviruses. Additionally, while the genetic diversity of some APMV species from wild birds in Europe and Asia has been explored (18,23,24), there is limited genetic information on APMVs originating in North America (5,13,(26)(27)(28). Thus, the goal of this study was to use MinION sequencing to detect and genetically characterize APMVs isolated from swabs collected from wild birds during 2016-2018 in the United States.…”