Detection and characterisation of adeno-, irido- and paramyxoviruses in reptiles

Abstract

Among reptiles, adenoviruses (AdVs) have most often been identified in squamates (lizards and snakes) associated with gastroenteritis and hepatitis or central nervous signs. These viruses have been isolated and/or genetically characterised only in a very few cases. We detected and characterised 5 types (9 sequence variants) of squamatid atadenoviruses (AtAdVs). From bearded dragons (Pogona vitticeps), an emerald monitor (Varanus prasinus) and an asp viper (Vipera aspis) only PCR detection was successful. However, from samples of two Gila monsters (Heloderma suspectum) and a Mexican beaded lizard (H. horridum), AdVs could be propagated on cell culture, yielding the first report of lizard AdV isolates (type 1 and 2; LAdV-1 & -2). Partial genome analysis of LAdV-1 & -2, from these two closely related hosts, along with the phylogenetic analysis of the other detected types, contributed to the hypothesis of coevolution and reptilian origin of genus Atadenovirus members. The partial genomes (17 kb, 13 kb) of the two LAdVs were most alike each other, and revealed highest similarity to the snake AdV-1 sequence from GenBank. Some genes found at the right end of these genomes, however, differed significantly from those in SnAdV-1. Most interesting of these differences was the presence of a second fiber gene in both LAdV types. Apparently both fibers are functional, and thus LAdVs are the first AtAdVs reported with more than one fiber.