Identification of a Novel Adélie Penguin Circovirus at Cape Crozier (Ross Island, Antarctica)

Abstract

Understanding the causes of disease in Antarctic wildlife is crucial, as many of these species are already threatened by environmental changes brought about by climate change. In recent years, Antarctic penguins have been showing signs of an unknown pathology: a feather disorder characterised by missing feathers, resulting in exposed skin. During the 2018–2019 austral summer breeding season at Cape Crozier colony on Ross Island, Antarctica, we observed for the first time an Adélie penguin chick missing down over most of its body. A guano sample was collected from the nest of the featherless chick, and using high-throughput sequencing, we identified a novel circovirus. Using abutting primers, we amplified the full genome, which we cloned and Sanger-sequenced to determine the complete genome of the circovirus. The Adélie penguin guano-associated circovirus genome shares <67% genome-wide nucleotide identity with other circoviruses, representing a new species of circovirus; therefore, we named it penguin circovirus (PenCV). Using the same primer pair, we screened 25 previously collected cloacal swabs taken at Cape Crozier from known-age adult Adélie penguins during the 2014–2015 season, displaying no clinical signs of feather-loss disorder. Three of the 25 samples (12%) were positive for a PenCV, whose genome shared >99% pairwise identity with the one identified in 2018–2019. This is the first report of a circovirus associated with a penguin species. This circovirus could be an etiological agent of the feather-loss disorder in Antarctic penguins.

Identification of Circovirus Genome in a Chinstrap Penguin (Pygoscelis antarcticus) and Adélie Penguin (Pygoscelis adeliae) on the Antarctic Peninsula

“…However, our knowledge of pathogen presence and prevalence in even the continent’s most iconic group of animals, penguins (order: Sphenisciformes), remains limited. To date, most studies of Antarctic penguin viral pathogens have focused on colonies located near fixed scientific research stations, which can monitor sites seasonally or, in some cases, year-round over several years [ 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 ].…”

“…A recent study of one of the world’s largest penguin colonies, the Cape Crozier Adélie Penguin ( Pygoscelis adeliae ) colony on Ross Island in East Antarctica, identified a novel circovirus associated with Adélie Penguins [ 3 ]. Circoviruses (family: Circoviridae ; genus: Circovirus ) are circular single-stranded DNA viruses that infect a variety of avian, fish, mammalian, and reptilian species.…”

“…Their genome encodes two genes in an ambisense orientation: the replication-associated protein ( rep ) in the virion sense and the capsid protein ( cp ) in the complementary sense [ 23 ]. The penguin circovirus (PenCV) was first noted in the guano of a chick exhibiting feather disorder in the 2018–2019 breeding season [ 3 ]. Subsequent analysis of cloacal swabs from the 2014–2015 breeding season also identified three other individuals with this virus sharing > 99% shared genome-wide identity [ 3 ].…”

“…The penguin circovirus (PenCV) was first noted in the guano of a chick exhibiting feather disorder in the 2018–2019 breeding season [ 3 ]. Subsequent analysis of cloacal swabs from the 2014–2015 breeding season also identified three other individuals with this virus sharing > 99% shared genome-wide identity [ 3 ]. Feather disorder in penguins was first observed in an Emperor Penguin ( Aptenodytes forsteri ) chick at Cape Washington, near the Ross Sea in 1996 [ 3 ] with subsequent observations in African Penguin ( Spheniscus demersus ) and Magellanic Penguin ( Spheniscus magellanicus ) chicks (Kane et al, 2010).…”

Special Issue “Emerging Viruses: Surveillance, Prevention, Evolution, and Control”

“…Chen et al [27] evaluate the genetic diversity of porcine circovirus 3 in China. Morandini et al [28] report a novel adélie penguin circovirus from Antarctica. Chen et al [29] present insights on the phylogeny and virulence of porcine reproductive and respiratory syndrome virus variants.…”