PARROT BORNAVIRUSES IN PSITTACINES KEPT IN CAPTIVITY IN THE STATE OF SANTA CATARINA, BRAZIL.

Parrot bornaviruses are responsible for proventricular dilatation disease (PDD) in psittacines. This study aimed to determine the occurrence and factors associated with Parrot bornaviruses infection in psittacines kept in captivity in a state in the southern region of Brazil. A cross-sectional study was carried out with 192 birds from two facilities (A and B) in 2019, using choanal, esophageal, and cloacal swabs and feathers, totaling 768 samples subjected to reverse-transcription polymerase chain reaction (RT-PCR), for the matrix (M) protein gene with a final product of 350 base pairs (bp). Genetic sequencing of three positive samples was performed by the Sanger method. In the study, the overall virus occurrence was 35.9% (69/192), with 40.4% (42/104) in Facility A and 30.7% (27/88) in Facility B. Sequencing analysis of the samples revealed the presence of Parrot bornavirus 2 (PaBV-2) in both facilities. Swab samples from the choanal (40/69), esophageal (30/69), cloacal (35/69), and feather (15/69) tested positive, facilitating the molecular diagnosis of Parrot bornaviruses. The results indicated that there is no single ideal sample type for antemortem molecular diagnosis of this virus. Simultaneously testing all four samples at the same time point yielded more diagnoses than testing any single sample among the four. Most of the 29 sampled psittacine species were native, and 46.9% of the birds (90/192) consisted of endangered species. Among the psittacines that tested positive, 88.4% (61/69) were clinically healthy, and 8.7% (6/69) exhibited clinical or behavioral signs, including behavioral changes, alterations in feathering, and changes in body score at the time of collection. This study showcases the application of minimally invasive sampling for diagnosing Parrot bornaviruses, enabling sample collection when the birds are restrained for clinical evaluation. This approach facilitates a prompt and effective antemortem diagnosis, thereby serving as an efficient screening method for parrots kept in captivity.

Surveillance of Parrot Bornavirus in Taiwan Captive Psittaciformes.

Parrot bornavirus (PaBV) is an infectious disease linked with proventricular dilatation disease (PDD) with severe digestive and neurological symptoms affecting psittacine birds. Despite its detection in 2008, PaBV prevalence in Taiwan remains unexplored. Taiwan is one of the leading psittacine bird breeders; hence, understanding the distribution of PaBV aids preventive measures in controlling spread, early disease recognition, epidemiology, and transmission dynamics. Here, we aimed to detect the prevalence rate of PaBV and assess its genetic variation in Taiwan. Among 124 psittacine birds tested, fifty-seven were PaBV-positive, a prevalence rate of 45.97%. Most of the PaBV infections were adult psittacine birds, with five birds surviving the infection, resulting in a low survival rate (8.77%). A year of parrot bornavirus surveillance presented a seasonal pattern, with peak PaBV infection rates occurring in the spring season (68%) and the least in the summer season (25%), indicating the occurrence of PaBV infections linked to seasonal factors. Histopathology reveals severe meningoencephalitis in the cerebellum and dilated cardiomyopathy of the heart in psittacine birds who suffered from PDD. Three brain samples underwent X/P gene sequencing, revealing PaBV-2 and PaBV-4 viral genotypes through phylogenetic analyses. This underscores the necessity for ongoing PaBV surveillance and further investigation into its pathophysiology and transmission routes.

Genetic trends in parrot Bornavirus: a clinical analysis.

Parrot Bornavirus (PaBV) has been reported to cause indigestion and other wasting symptoms such as weight loss and lethargy. The pathogenesis of PaBV has yet to be fully elucidated. This study reports PaBV infections in South Korea and suggests a trend in the genetic information gathered from clinical cases. A total of 487 birds with or without clinical symptoms were tested for bornavirus. Twelve of 361 asymptomatic birds tested positive for bornavirus, while 15 of 126 birds with various symptoms tested positive. A segment of approximately 1,540 bps including the N, X, P and M proteins were obtained from 23 of the positive strains and analyzed with other strains found on GenBank that had clinical information. PaBV was type 2 and 4 in South Korea, and certain amino acid sequences showed a difference between symptom presenting animals and asymptomatic animals in the X protein and P protein. When considering that some asymptomatic cases may have been latent infections at the time of examination, it is plausible these trends may grow stronger with time. Majority of PaBV was type 4 in South Korea. If these trends are confirmed, diagnosis of potentially pathogenic PaBVs in a clinical manner will be possible during the early stages of infection.

Experimental infection of aquatic bird bornavirus 1 (ABBV-1) in Canada geese (Branta canadensis).

Aquatic bird bornavirus 1 (ABBV-1) has a high prevalence of infection in certain North American populations of Canada geese (Branta canadensis), suggesting a possible role of these birds as an ABBV-1 reservoir. The goal of this study was to evaluate the ability of Canada geese to become experimentally infected with ABBV-1, develop lesions, and transmit the virus to conspecifics. One-week-old Canada geese (n, 65) were inoculated with ABBV-1 through the intramuscular (IM) or cloacal (CL) routes, with the control group receiving carrier only. An additional 6 geese were added to each group to test horizontal transmission (sentinel birds). Geese were monitored daily, and selected birds were euthanized at 1, 8, and 15-weeks post infection (wpi) to assess virus replication in tissues and lesion development. At 15 wpi, over 70% of IM birds were infected, while the CL route yielded only 1 infected goose. Of the infected IM geese, 26% developed encephalitis and/or myelitis after 8 wpi. No clinical signs were observed, and no sentinel birds became infected in any group. Only 1 oropharyngeal swab (IM group) tested positive for ABBV-1 RNA, while the water from the enclosures was consistently negative for virus RNA. This study documents successful experimental infection of Canada geese with ABBV-1, with findings comparable to what is described in infection trials with other waterfowl species. However, minimal shedding and lack of environmental dispersal indicate that Canada geese have little potential to disseminate the virus among wild waterfowl, and that other species could be better suited to act as chronic ABBV-1 shedders in the wild.

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

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.