Phylogenetic and pathogenic characterization of novel adenoviruses isolated from long-tailed ducks (Clangula hyemalis)

Propagation and Molecular Characterization of Fowl Adenovirus Serotype 8b Isolates in Chicken Embryo Liver Cells Adapted on Cytodex™ 1 Microcarrier Using Stirred Tank Bioreactor

Large volume production of vaccine virus is essential for prevention and control of viral diseases. The objectives of this study were to propagate Fowl adenovirus (FAdV) isolate (UPM08136) in chicken embryo liver (CEL) cells adapted to Cytodex™ 1 microcarriers using stirred tank bioreactor (STB) and molecularly characterize the virus. CEL cells were prepared and seeded onto prepared Cytodex™ 1 microcarriers and incubated first in stationary phase for 3 h and in STB at 37 °C, 5% CO2, and 20 rpm for 24 h. The CEL cells were infected with FAdV isolate (UPM08136) passage 5 (UPM08136CELP5) or passage 20 (UPM08136CELP20) and monitored until cell detachment. Immunofluorescence, TCID50, sequencing, alignment of hexon and fiber genes, and phylogenetic analysis were carried out. CEL cells were adapted well to Cytodex™ 1 microcarriers and successfully propagated the FAdV isolates in STB with virus titer of 107.5 (UPM08136CELP5B1) and 106.5 (UPM08136CELP20B1) TCID50/mL. These isolates clustered with the reference FAdV serotype 8b in the same evolutionary clade. The molecular characteristics remained unchanged, except for a point substitution at position 4 of the hexon gene of UPM08136CELP20B1, suggesting that propagation of the FAdV isolate in STB is stable and suitable for large volume production and could be a breakthrough in the scale-up process.

Necrotizing Ventriculitis in Fledgling Chimney Swifts (Chaetura Pelagica) Associated With a Novel Adenovirus, Chimney Swift Adenovirus-1 (CsAdV-1)

Five chimney swift fledglings died following a progressive loss of appetite and condition while being cared for by an experienced wildlife rehabilitator. All animals had severe necrotizing and heterophilic ventriculitis, with myriad epithelial cells characterized by karyomegaly with intranuclear inclusion bodies. Transmission electron microscopy showed distention of epithelial cell nuclei and chromatin peripheralization by nonenveloped, icosahedral, 75- to 85-nm-diameter virions. Degenerate nested PCR for a highly conserved region of the adenovirus DNA polymerase gene was positive. BLAST analysis of the amplicon sequence indicated the presence of a novel adenovirus, with 74% homology to Antarctic penguin adenoviruses and 72% homology to a bat adenovirus, at low query coverages of only 65% and 63%, respectively. BLAST analysis of the predicted amino acid sequence generated the highest scores for squamate adenoviruses at 100% query coverage. Based on phylogenetic analysis of the partial amino acid sequence of the DNA polymerase, the chimney swift virus was a novel adenovirus most closely related to the Atadenovirus genus. Using a probe based on the novel viral sequence, DNA in situ hybridization identified viral nucleic acid in the nucleus. While the tentatively named chimney swift adenovirus-1 (CsAdV-1) is so far classified with the Atadenoviruses, it is relatively divergent from other members of that genus and may represent the first identified member of a new genus of Adenoviruses.

Parasites of seabirds: A survey of effects and ecological implications

Parasites are ubiquitous in the environment, and can cause negative effects in their host species. Importantly, seabirds can be long-lived and cross multiple continents within a single annual cycle, thus their exposure to parasites may be greater than other taxa. With changing climatic conditions expected to influence parasite distribution and abundance, understanding current level of infection, transmission pathways and population-level impacts are integral aspects for predicting ecosystem changes, and how climate change will affect seabird species. In particular, a range of micro- and macro-parasites can affect seabird species, including ticks, mites, helminths, viruses and bacteria in gulls, terns, skimmers, skuas, auks and selected phalaropes (Charadriiformes), tropicbirds (Phaethontiformes), penguins (Sphenisciformes), tubenoses (Procellariiformes), cormorants, frigatebirds, boobies, gannets (Suliformes), and pelicans (Pelecaniformes) and marine seaducks and loons (Anseriformes and Gaviiformes). We found that the seabird orders of Charadriiformes and Procellariiformes were most represented in the parasite-seabird literature. While negative effects were reported in seabirds associated with all the parasite groups, most effects have been studied in adults with less information known about how parasites may affect chicks and fledglings. We found studies most often reported on negative effects in seabird hosts during the breeding season, although this is also the time when most seabird research occurs. Many studies report that external factors such as condition of the host, pollution, and environmental conditions can influence the effects of parasites, thus cumulative effects likely play a large role in how parasites influence seabirds at both the individual and population level. With an increased understanding of parasite-host dynamics it is clear that major environmental changes, often those associated with human activities, can directly or indirectly affect the distribution, abundance, or virulence of parasites and pathogens.