Detection of a new avian bornavirus in barn owl (Tyto alba) by pan-viral microarray

Highlights

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  New virus discovered in a barn Owl from Spain showing clinical signs of neurological disease.

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  The virus is named Barn owl bornavirus 1 (BoBV-1) and belongs to the Orthobornavirus serini species.

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  Pan-viral microarray is advantageous when conventional diagnostic techniques fail.

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  The pan-viral microarray used showed capacity to detect new viruses and viral variants.

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  This technology can be valuable in emergencies requiring high-sensitive wide-range detection tools.

Abstract

A barn owl (Tyto alba) died with neurological signs compatible with a viral infection. After discarding other possible infections caused by circulating viruses in the area, analysis of the central nervous system using a pan-viral microarray revealed hybridization to canary bornavirus 2 (CnBV-2). Subsequent sequence analysis confirmed the presence of a virus sharing more than 83% identity with CnBV-2. Surprisingly, the new sequence corresponds to a new virus, here named Barn owl Bornavirus 1 (BoBV-1), within the Orthobornavirus serini species. Moreover, it is the first member of this species that has been detected in a non-passerine bird, indicating that Orthobornavirus serini species comprises viruses with a wider range of hosts than previously presumed. The use of this microarray has proven to be an excellent tool for viral detection in clinical samples, with capacity to detect new viral variants. This allows the diagnosis of a great range of viruses, which can cause similar disease symptoms and which identification by PCR methods might be tedious, probably unsuccessful and, in the long run, expensive. This platform is highly useful for a fast and precise viral detection, contributing to the improvement of diagnostic methods.

Bornaviruses are negative sense single-stranded RNA viruses belonging to the family Bornaviridae that include relevant pathogens of animals, some of them zoonotic, severely affecting humans. They were first identified in 2008, in avian psittacine) hosts suffering from proventricular dilatation disease (PDD) (Honkavuori et al., 2008, Kistler et al., 2008). Since then, many bornaviruses have been identified around the world, affecting avian (Guo et al., 2012, Guo et al., 2013, Guo et al., 2014, Heffels-Redmann et al., 2011, Komorizono et al., 2016, Payne et al., 2011, Rubbenstroth et al., 2014, Sa-ardta et al., 2019; Sassa et al. 2015; Weissenböck et al., 2009a, 2009b), mammal (Hoffmann et al., 2015) and reptile species (Hyndman et al., 2018).

Recently, the taxonomy of bornaviruses has been reorganized. According to the new classification, the family Bornaviridae now includes three genera, genus Carbovirus, genus Cultervirus and genus Orthobornavirus (previously named Bornavirus), which comprise at least nine species, according to ICTV: Orthobornavirus alphapsittaciforme, Orthobornavirus avisaquaticae, Orthobornavirus betapsittaciforme, Orthobornavirus bornaense, Orthobornavirus caenophidiae, Orthobornavirus elapsoideae, Orthobornavirus estrildidae, Orthobornavirus sciuri and Orthobornavirus serini. Indeed, there are some unassigned bornaviruses, such as Gabon viper virus 1, which still remain unclassified (Rubbenstroth, 2022). In contrast to classical mammalian orthobornaviruses, which are assigned to two species, avian species appear to have a much higher genetic heterogeneity. After the first identification of a bornavirus as the causative agent for PDD, a disease of avian hosts, (Honkavuori et al., 2008, Kistler et al., 2008), further bornavirus infections in psittacines originating from Germany, Israel, USA, Austria, Switzerland, Hungary, Australia, Italy, Spain, UK and Denmark (Weissenböck et al., 2009a, Heffels-Redmann et al., 2011) were detected. Moreover, a report on the detection of a bornavirus genome in a canary (Serinus canaria) in Austria (Weissenböck et al., 2009b) with enteric ganglioneuritis and encephalitis indicated that Psittacidae are not the only family of birds susceptible for bornaviruses. Later, a new bornavirus was found in captive estrildid finches (Estrildidae) in Germany (Rubbenstroth et al., 2014), showing that passerines other than canaries can also host bornavirus infections.

The Orthobornavirus serini species (genus Orthobornavirus), currently comprises four separate viruses, three of them identified in canaries, named CnBV (for “Canary bornavirus”)-1, CnBV-2 and CnBV-3 and a fourth one named munia bornavirus 1 (MuBV-1) identified in a Bengalese finch (Lonchura striata) (Rubbenstroth, 2022). Classical detection methods for CnBV and other orthobornavirus diagnosis mainly include viral isolation, indirect immunofluorescence, immunohistochemistry, ELISA, RT-PCR and qRT-PCR (Rubbenstroth et al., 2013, Rubbenstroth et al., 2014, Sa-ardta et al., 2019).

Microarray technologies are excellent diagnostic tools to be applied as last resource on cases where conventional tests fail to establish the etiological agent causing a disease. They also provide rapid and sensitive methods for convenient detection of viral infections, surveillance of newly emerging viruses as well as disease control (Sultankulova et al., 2017). Thus, the pan-viral microarray assay performed in this study (Rosenstierne et al., 2014) offers a useful way to reveal the presence of both pathogenic and non-pathogenic viral species in samples where the attention is focused on the identification of a particular agent for a specific disease condition.

In this study, we report the discovery and genetic characterization of a new bornavirus within the Orthobornavirus serini species, detected in a barn owl (Tyto alba) by applying a pan-viral microarray method.

Detection of a new avian bornavirus in barn owl (Tyto alba) by pan-viral microarray - ScienceDirect