A novel adenovirus in Chinstrap penguins (Pygoscelis antarctica) in Antarctica

Abstract

Adenoviruses (family Adenoviridae) infect various organ systems and cause diseases in a wide range of host species. In this study, we examined multiple tissues from Chinstrap penguins (Pygoscelis antarctica), collected in Antarctica during 2009 and 2010, for the presence of novel adenoviruses by PCR. Analysis of a 855-bp region of the hexon gene of a newly identified adenovirus, designated Chinstrap penguin adenovirus 1 (CSPAdV-1), showed nucleotide (amino acid) sequence identity of 71.8% (65.5%) with South Polar skua 1 (SPSAdV-1), 71% (70%) with raptor adenovirus 1 (RAdV-1), 71.4% (67.6%) with turkey adenovirus 3 (TAdV-3) and 61% (61.6%) with frog adenovirus 1 (FrAdV-1). Based on the genetic and phylogenetic analyses, CSPAdV-1 was classified as a member of the genus, Siadenovirus. Virus isolation attempts from kidney homogenates in the MDTC-RP19 (ATCC® CRL-8135™) cell line were unsuccessful. In conclusion, this study provides the first evidence of new adenovirus species in Antarctic penguins.

Figure 1

Differences of the amino acid sequence in the partial hexon gene of novel Chinstrap penguin adenoviruses. Within the 285-amino acid region, six amino acid changes were found between CSPAdVno1 and no2, no4 and no8 (residues 134, 154, 159, 169, 215 and 226), and 12-amino acid differences were found between CSPAdVno1 and no3, no5, no6 and no7 (residues 134, 152, 157, 159, 166, 169, 194, 203, 215, 226, 241 and 242). A deletion of an amino acid at position 242 was found in the hexon gene of CSPAdVno1, no2, no4 and no8 (gray rectangle, deletion of amino acid residue G; CAG, nucleotide sequences in 722–724 nt).

Figure 2

Phylogenetic relationship between Chinstrap penguin adenovirus (CSPAdV-1) and other adenoviruses. The phylogenetic tree, based on nucleotide (a) and amino acid sequences (b) of the hexon protein contained loop regions, was generated by the neighbor-joining method. CSPAdVno1 to no8 (KC593379 to KC593386) were compared with adenoviruses of five genera: bat adenovirus 3 (BtAdV-3, GU226970), canine adenovirus 2 (CAdV-2, U77082), bat adenovirus 2 (BtAdV-2. NC015932), porcine adenovirus 5 (PAdV-5, AF289262), porcine adenovirus 3 (PAdV-3, AB126117), bovine adenovirus 10 (BAdV-10, AAF82136), murine adenovirus 1 (MAdV-1, NC000942), human adenovirus 11 (HAdV-11, AY163756)), simian adenovirus 25 (SAdV-25, AF394196), human adenovirus 2 (HAdV-2, J01917), human adenovirus 12 (HAdV-12, X73487), human adenovirus 40 (HAdV-40, L19443), bovine adenovirus 3 (BAdV-3, AF030154), tree shrew adenovirus 1 (TSAdV-1, AF258784), duck adenovirus 1 (DAdV-1, Y09598), ovine adenovirus 7 (OAdV-7, U40839), fowl adenovirus 9 (FAdV-9, AF083975), fowl adenovirus 1 (FAdV-1, U46933), fowl adenovirus 4 (FAdV-4, NC015323), frog adenovirus 1 (FrAdV-1, AF224336), great tit adenovirus 1 (GTAdV-1, FJ849795), turkey adenovirus 3 (TAdV-3, AC000016), raptor adenovirus 1 (RAdV-1, EU715130) and South Polar skua adenovirus 1 (SPSAdV-1, HM585353). Scale bars indicate the number of nucleotide and amino acid substitutions per site. Bootstrap values are given at the respective nodes, as determined for 1000 iterations using the MEGA5.1 software [26].

Figure 3

Collection site of Chinstrap penguin carcasses. Dead Chinstrap penguins were collected at Narębski Point (Antarctic Specially Protected Area; ASPA No. 171, red circle) on King George Island, Antarctica.