Inclusion body hepatitis in a tawny frogmouth (Podargus strigoides: Caprimulgiformes)

Characterisation of a novel aviadenovirus associated with disease in tawny frogmouths (Podargus strigoides)

Aviadenoviruses are widespread in wild birds but rarely cause disease in nature. However, when naïve species are exposed to poultry or aviaries, aviadenoviruses can lead to disease outbreaks. This study characterised a novel aviadenovirus infection in a native Australian bird, the tawny frogmouth (Podargus strigoides) during an outbreak investigation. The identified complete genome of aviadenovirus, named tawny frogmouth aviadenovirus A (TwAviAdV-A) was 41,175 bp in length containing 52 putative genes. TwAviAdV-A exhibits the common aviadenovirus genomic organisation but with a notable monophyletic subclade in the phylogeny. The TwAviAdV-A virus was hepatotrophic and the six frogmouths presented to the wildlife hospitals in South Eastern Queensland most commonly exhibited regurgitation (in four frogmouths). Three were died or euthanized, two recovered, and one showed no signs. The detection of TwAviAdV-A in frogmouths coming into care re-emphasizes the need for strict biosecurity protocols in wildlife hospitals and care facilities.

Current epidemiological situation in the context of inclusion body hepatitis in poultry flocks in Poland

The research has been undertaken to understand the spreading of adenovirus strains in Poland's poultry flocks in the last six years. One hundred and forty-nine herds suspected of infection with adenoviruses were tested and the presence of poultry adenoviruses was found in 86 studied herds which were about 57,71% of examined flocks. Thirty-eight (44.18%) strains were connected with the infection of inclusion body hepatitis, 11 (12.79%) strains were isolated from digestive system dysfunction, 33 (38.37%) strains had been obtained from the flocks with no symptomatic changes/behaviour, and four (4.65%) strains were obtained from flocks with the manifestation of depression. Sequencing analysis was based on Loop L1 region of the HVR1-4 fragment of the hexon gene. The adenovirus strains were classified into five species FAdV-A-E, belonging to the following eight serotypes: FAdV-1/A, FAdV-5/B, FAdV-3/10/C, FAdV-9/11/D, and FAdV-7/8a/E. The most common serotype in poultry turned out to be type/species FAdV-11/D, FAdV-5/B, and FAdV-7/8b/E while the least frequent was type/species FAdV-3/10/C (only four and two strains respectively of this types were isolated with the following range: FAdV-1/A 6 (6.97%), FAdV-5/B 24 (27,90%), FAdV-3/C 4 (4,65%), FAdV-10/C 2 (2,32%), FAdV-11/D 36 (41,86%), and FAdV-E 14 (16.27%). The understanding of genetic diversity, geographic distribution, and antigenic properties of fowl adenovirus strains (FAdVs) isolated in Poland have been evaluated.

Isolation and molecular characterization of Fowl adenovirus strains in Black grouse: First reported case in Poland

This article describes the isolation, molecular characterization, and genotyping of two fowl adenovirus (FAdVs) strains with GenBank Accession numbers (MT478054, JSN-G033-18-L and MT478055, JSN-G033-18-B) obtained from the internal organs of black grouse (Lyrurus tetrix). This study also reveals the first confirmation of fowl adenovirus in Poland, supporting one of the hypotheses about the probability of fowl adenovirus interspecies transmission. The adenovirus strain sequences were investigated via phylogenetic analysis and were found to have an overall mean pairwise distance of 2.189. The heterogeneity, Relative Synonymous Codon Usage (RSCU), codon composition, and nucleotide frequencies were examined. Statistical analyses and Tajima’s test for the examined sequences were carried out. The Maximum Likelihood for the examined sequences substitutions was performed. The results of the sequence analysis identified MT478054, JSN-G033-18-L and MT478055, JSN-G033-18-B as strains of fowl adenovirus 2/11/D, with the Fowl adenovirus D complete sequence showing a 93% match. Wild birds may act as a natural reservoir for FAdVs and likely play an important role in the spreading of these viruses in the environment. The findings reported here suggest horizontal transmission within and between avian species.

Detection of fowl adenovirus D strains in wild birds in Poland by Loop-Mediated Isothermal Amplification (LAMP)

BACKGROUND

The present study on the role of strains of adenovirus in wildlife reservoirs, and their prevalence is under exploration. In several previous studies, the presence of adenovirus strains in wild birds has been investigated. Worldwide distribution and outbreaks of adenovirus infections have been reported by many authors. The present study investigated the prevalence of FAdVs in 317 samples of different bird species from the northwestern region of Poland. An applied specific, sensitive, and efficient, without cross-reactivity loop-mediated isothermal amplification (LAMP) method to gauge the prevalence of fowl adenovirus strains in wild birds was developed and used.

RESULTS

The method was based on the sequence of the loop L1 HVR1-4 region of the hexon gene of the FAdV genome reference strains FAdV-2 KT862805 (ANJ02325), FAdV-3 KT862807 (ANJ02399) and FAdV-11 KC750784 (AGK29904). The results obtained by LAMP were confirmed by real-time PCR. Among 317 samples obtained from wild birds, eight FAdV isolates (2.52%) were identified and produced a cytopathic effect (CPE) in chicken embryo kidney cells (CEK). Three FAdV types belonging to species Fowl adenovirus D were detected, which were isolated from three adenovirus types 2/3/11, and have been confirmed in three mute swans (Cygnus olor), three wild ducks (Anas platyrhynchos), one owl (Strigiformes), and one common wood pigeon (Columba palumbus).

CONCLUSIONS

This study provides the first accurate quantitative data for the replication of fowl adenovirus strains in wild birds in Poland, indicating adenovirus interspecies transmission, and demonstrating the circulation of FAdVs in wild birds.

Disease surveillance in wild Victorian cacatuids reveals co-infection with multiple agents and detection of novel avian viruses

Wild birds are known reservoirs of bacterial and viral pathogens, some of which have zoonotic potential. This poses a risk to both avian and human health, since spillover into domestic bird populations may occur. In Victoria, wild-caught cockatoos trapped under licence routinely enter commercial trade. The circovirus Beak and Feather Disease Virus (BFDV), herpesviruses, adenoviruses and Chlamydia psittaci have been identified as significant pathogens of parrots globally, with impacts on both aviculture and the conservation efforts of endangered species. In this study, we describe the results of surveillance for psittacid herpesviruses (PsHVs), psittacine adenovirus (PsAdV), BFDV and C. psittaci in wild cacatuids in Victoria, Australia. Samples were collected from 55 birds of four species, and tested using genus or family-wide polymerase chain reaction methods coupled with sequencing and phylogenetic analyses for detection and identification of known and novel pathogens. There were no clinically observed signs of illness in most of the live birds in this study (96.3%; n = 53). Beak and Feather Disease Virus was detected with a prevalence of 69.6% (95% CI 55.2-80.9). Low prevalences of PsHV (1.81%; 95% CI 0.3-9.6), PsAdV (1.81%; 95% CI 0.3-9.6), and C. psittaci (1.81%; 95% CI 0.3-9.6) was detected. Importantly, a novel avian alphaherpesvirus and a novel avian adenovirus were detected in a little corella (Cacatua sanguinea) co-infected with BFDV and C. psittaci. The presence of multiple potential pathogens detected in a single bird presents an example of the ease with which such infectious agents may enter the pet trade and how novel viruses circulating in wild populations have the potential for transmission into captive birds. Genomic identification of previously undescribed avian viruses is important to further our understanding of their epidemiology, facilitating management of biosecurity aspects of the domestic and international bird trade, and conservation efforts of vulnerable species.