A Psittacus Erithacus naturally infected with parrot Bornavirus 4

Exotics Medicine

A Psittacus Erithacus naturally infected with parrot Bornavirus: clinical condition, necropsy findings and strain characterization – Dr. Hélder Craveiro, Hospital Veterinário Baixo Vouga, Portugal.

 

Parrot bornavirus 1 to 8 (PaBV-1 to 8) are non-segmented negative-stranded RNA viruses that cause a chronic and fatal condition in psittacines characterized by neurological and/or gastrointestinal signs (Tizard et al. 2016). The aim of this case report was to identify the etiologic agent responsible for a severe condition developed by a female parrot from a captive flock, as well as to characterize the clinical features and to report the necropsy findings.

A female Psittacus erithacus with a two month history of clinical signs compatible with avian bornaviruses died, and a necropsy was made. Tissue samples from brain, lung, trachea, heart, liver, spleen, kidney, crop, proventriculus, ventricle, intestine (including duodenum, jejunum, ileum and colon) and pancreas were collected. All tissue samples were tested by real-time PCR SYBR® Green-based assay, using a set of primers that targeted a region of the phosphoprotein gene (Pinto et al.2018). The positive samples by real-time PCR SYBR® Green-based assay were analysed by conventional PCR, aiming to recover one-sixth of the viral genome for sequencing purposes, according with previously reported (Pinto et al., 2018). The BLAST® was used to find regions of similarity with the nucleotide sequence database of the GenBank®. Bioinformatic analyses were conducted based on genes (N, X, P and M).

In GenBank® database we search for nucleotide sequences from bornaviruses belonging to the same taxonomic group (strain) of the etiologic agent identified in the present study. From the nucleotide sequences that fulfilled the criteria to be included in the analysis, we collected information on the country origin of parrots and number of strains reported. We used BLAST® (https://blast.ncbi.nlm.nih.gov/Blast.cgi) to find regions of similarity between sequences obtained and the GenBank® as to estimate the percent identity (id%) between them.

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Fig.1.

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Figure 2. The severe dilatation (asterisk) produced a small rupture in the proventriculus wall (arrow).

The pet parrot had necropsy findings/lesions compatible with avian bornavírus infection, including cachexia, dilation and undigested food in the proventriculus and splenomegaly. All tissues samples were positive by real-timePCR SYBR® Green-based assay. From all tissues, one-sixth of the viral genome was recovered (including the gene N, X, P and M) and nucleotide sequences analysis revealed infection by parrot bornavirus 4 (PaBV-4) (Ident=99%; E-value=0.0).

From GenBank® data base, we found 167 nucleotide sequences of PaBV-4 that fulfilled the criteria to be included in the analysis (Figure 3). The nucleotide sequences of PaBV-4 (n=167) were from 13 countries, distributed around the world (Figure 3), and Germany presented the highest number of cases reported (n=74) (Figure 3). The PaBV-4 strain identified in the present study was more genetically identical with some of the strains reported from Austria, Switzerland and Thailand (Figure 3). Additionally, the most divergent PaBV-4 strains found, compared with our strain, were reported from Brazil, Italy and Spain (Figure 3).

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Figure 3. Worldwide distribution of the 167 parrot bornavirus 4 (PaBV-4) strains identified in samples of captive psittacines, sampled in 13 countries and reported in GenBank® database.

 

Bibliography

Tizard I, Shivaprasad HL, Guo J, Hameed S, Ball J, Payne S. The pathogenesis of proventricular dilatation disease. Animal Health Research Reviews 2017,110 – 126.

Marlene Cavaleiro Pinto, Veronica Rondahl, Mikael Berg, Erik Ågren, Júlio Carvalheira, Gertrude Thompson & Jonas Johansson Wensman(2019)Detection and phylogenetic analysis of parrot bornavirus 4 identified from a Swedish Blue-winged macaw (Primolius maracana) with unusual nonsuppurative myositis,Infection Ecology & Epidemiology,9:1,DOI: 10.1080/20008686.2018.1547097.