Laboklin GmbH & Co. KG, Bad Kissingen, Germany
Adenoviruses are well known pathogens in squamate reptiles, but reports in chelonians are rarer and have included genetically more diverse viruses. Samples from 949 chelonians were tested for adenoviral DNA by PCR.3 PCR products were then sequenced in order to partially characterize the detected viruses. Adenoviruses were detected in 22 (2.3%) of the animals tested, including 13 terrestrial tortoises, 8 aquatic turtles, and one chelonian of unknown species. Detection rates were higher in aquatic species than in tortoises. Sequencing showed that 6 of the detected adenoviruses clustered in the genus Atadenovirus, while the remaining 16 detected viruses clustered in the proposed genus “Testadenovirus.” The atadenoviruses were all detected in tortoises, while testadenoviruses were detected in terrestrial and aquatic species. The testadenoviruses detected clustered according to their chelonian host species, with distinct groups for terrestrial and for aquatic hosts, while the atadenoviruses were genetically diverse. Atadenoviruses are commonly detected in squamate reptiles, but have only been previously described in chelonians in a single case report.2 Testadenoviruses, on the other hand, are hypothesized to have co-evolved with chelonians.1 The results of this study support previous findings that testadenoviruses may be host species specific, while atadenoviruses appear able to broadly switch hosts. Their detection in several species of tortoises significantly expands the numbers of these viruses detected in chelonians. The clinical impact of these genetically diverse viruses on their hosts is not known and requires further study.
1. Doszpoly A, Wellehan JF, Jr, Childress AL, Tarján ZL, Kovács ER, Harrach B, Benkő M. Partial characterization of a new adenovirus lineage discovered in testudinoid turtles. Infect Genet Evol. 2013;17:106–112.
2. Garcia-Morante B, Pénzes JJ, Costa T, Martorell J, Martínez J. Hyperplastic stomatitis and esophagitis in a tortoise (Testudo graeca) associated with an adenovirus infection. J Vet Diagn Invest. 2016;28(5):579–583.
3. Wellehan JFX, Johnson AJ, Harrah B, Benkő M, Pessier AP, Johnson CM, Garner MM, Childress A, Jacobson ER. Detection and analysis of six lizard adenoviruses by consensus primer PCR provides further evidence of a reptilian origin for the atadenoviruses. J Virol. 2004;78:13366–13369.