Avian Bornaviruses in Wild Aquatic Birds of the Anseriformes Order in Poland

Abstract

Bornaviruses are a diverse family of viruses infecting various hosts, including birds. Aquatic bird bornavirus 1 (ABBV-1) and aquatic bird bornavirus 2 (ABBV-2) have been found in wild waterfowl but data on their prevalence are scarce. To gain knowledge on the occurrence of ABBVs in Poland, samples originating from dead birds of the Anseriformes order collected in 2016–2021 were tested with a real time RT-PCR method targeting the ABBVs genome. A total of 514 birds were examined, including 401 swans, 96 ducks and 17 geese. The presence of ABBV-1 RNA was detected in 52 swans (10.1% of all tested birds) from 40 different locations. No positive results were obtained for ducks and geese. Sequences of about 2300 bases were generated for 18 viruses and phylogenetic analysis was performed. A relatively low genetic diversity of the examined ABBV-1 strains was observed as all were gathered in a single cluster in the phylogenetic tree and the minimum nucleotide identity was 99.14%. The Polish strains were closely related to ABBV-1 identified previously in Denmark and Germany, but a limited number of sequences from Europe hinders the drawing of conclusions about interconnections between Polish and other European ABBVs. The results of the present study provide new insights into the distribution and genetic characteristics of ABBVs in wild birds in Europe.

Experimental infection of aquatic bird bornavirus in Muscovy ducks

“…Since its original description, ABBV-1 has been detected or isolated from multiple species of waterfowl 11 , 12 , both in asymptomatic and neurologically affected birds, and sporadically in birds outside the Anseriformes order, including gulls 13 , bald eagles 6 , and an emu 14 . In fact, epidemiological studies have shown that wild waterfowl species appear to be the largest reservoir of ABBV-1 in North America and Europe, with an estimated prevalence of up to 50%, in some populations depending on species, flock, and location 15 – 20 . Aquatic bird bornaviruses, therefore, could be considered as primarily waterfowl viruses that may sporadically infect or become established in new avian populations 6 , as also supported by phylogenetic analysis, which suggests that horizontal spread is a driving force of interspecies transmission of bornaviruses in avian species 19 .…”

Transcriptome Analysis of Duck and Chicken Brains Infected with Aquatic Bird Bornavirus-1 (ABBV-1)

“…In mammalian species, Borna disease virus 1 (BoDV-1, the type-species of the Orthobornavirus genus, causes Borna disease, a neurological affliction of sheep and horses in central Europe [ 4 ]. Aquatic bird bornavirus-1 (ABBV-1), in the Orthobornavirus avisaquaticae species, has been identified in wild waterfowl in North America and Europe, and it has been associated with both asymptomatic infections and symptomatic infections (neurological signs, proventricular dilation, and wasting) [ 5 , 6 , 7 , 8 , 9 , 10 ]. ABBV-1 has a broad host range, and natural infection with this virus has been identified in ratites, raptors, and gulls, which are taxonomically distant from waterfowl species [ 11 , 12 , 13 ].…”