Phylogenetic analyses of novel squamate adenovirus sequences in wild-caught Anolis lizards.

Jill M Ascher,Julienne Ng,Jeffrey D Wyatt,Richard E Glor,Anthony J Geneva,Justin David Brown

doi:10.1371/journal.pone.0060977

Jill M Ascher, Julienne Ng + Show 4 more

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https://doi.org/10.1371/journal.pone.0060977

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Abstract

Adenovirus infection has emerged as a serious threat to the health of captive snakes and lizards (i.e., squamates), but we know relatively little about this virus' range of possible hosts, pathogenicity, modes of transmission, and sources from nature. We report the first case of adenovirus infection in the Iguanidae, a diverse family of lizards that is widely-studied and popular in captivity. We report adenovirus infections from two closely-related species of Anolis lizards (anoles) that were recently imported from wild populations in the Dominican Republic to a laboratory colony in the United States. We investigate the evolution of adenoviruses in anoles and other squamates using phylogenetic analyses of adenovirus polymerase gene sequences sampled from Anolis and a range of other vertebrate taxa. These phylogenetic analyses reveal that (1) the sequences detected from each species of Anolis are novel, and (2) adenoviruses are not necessarily host-specific and do not always follow a co-speciation model under which host and virus phylogenies are perfectly concordant. Together with the fact that the Anolis adenovirus sequences reported in our study were detected in animals that became ill and subsequently died shortly after importation while exhibiting clinical signs consistent with acute adenovirus infection, our discoveries suggest the need for renewed attention to biosecurity measures intended to prevent the spread of adenovirus both within and among species of snakes and lizards housed in captivity.

Highlights

Recent studies identify a growing number of viruses that infect reptiles [1,2]
Adenoviruses appear enzootic to captive populations of bearded dragons and other popular captive reptiles, we know relatively little about the extent of their phylogenetic distribution across the host clade, pathogenicity, modes of transmission, and sources in nature
AT content was 51.9% and 47.6% for A. d. ignigularis and A. d. ravitergum adenovirus sequences, respectively, similar to AT richness observed in other squamate Atadenovirus sequences (AT 41.1–56.3%), and in contrast to the more extreme AT bias observed in Atadenovirus sequences reported from mammals and birds [36]

Summary

Introduction

Recent studies identify a growing number of viruses that infect reptiles [1,2]. The adenoviruses-a group of non-enveloped, double-stranded DNA viruses characterized by intermediate genome size (26–45 KB) and a distinctive icosahedral structurehave emerged as a potentially serious threat to the health of captive reptiles [3,4,5,6,7]. Adenoviruses occur as pathogens across vertebrates, including humans, and are widespread among squamate reptiles (i.e., snakes and lizards) (Table 1). Case reports of reptiles infected with adenovirus have been on the rise in recent years and include 28 species sampled from across the squamate phylogenetic tree (Fig. 1, Table 1). Most of these infections are reported from captive animals and the list of afflicted species reads like a who’s who of the species most popular among reptile hobbyists. Adenoviruses appear enzootic to captive populations of bearded dragons and other popular captive reptiles, we know relatively little about the extent of their phylogenetic distribution across the host clade, pathogenicity, modes of transmission, and sources in nature

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