Detection and Characterization of Invertebrate Iridoviruses Found in Reptiles and Prey Insects in Europe over the Past Two Decades

Abstract

Invertebrate iridoviruses (IIVs), while mostly described in a wide range of invertebrate hosts, have also been repeatedly detected in diagnostic samples from poikilothermic vertebrates including reptiles and amphibians. Since iridoviruses from invertebrate and vertebrate hosts differ strongly from one another based not only on host range but also on molecular characteristics, a series of molecular studies and bioassays were performed to characterize and compare IIVs from various hosts and evaluate their ability to infect a vertebrate host. Eight IIV isolates from reptilian and orthopteran hosts collected over a period of six years were partially sequenced. Comparison of eight genome portions (total over 14 kbp) showed that these were all very similar to one another and to an earlier described cricket IIV isolate, thus they were given the collective name lizard–cricket IV (Liz–CrIV). One isolate from a chameleon was also subjected to Illumina sequencing and almost the entire genomic sequence was obtained. Comparison of this longer genome sequence showed several differences to the most closely related IIV, Invertebrate iridovirus 6 (IIV6), the type species of the genus Iridovirus, including several deletions and possible recombination sites, as well as insertions of genes of non-iridoviral origin. Three isolates from vertebrate and invertebrate hosts were also used for comparative studies on pathogenicity in crickets (Gryllus bimaculatus) at 20 and 30 °C. Finally, the chameleon isolate used for the genome sequencing studies was also used in a transmission study with bearded dragons. The transmission studies showed large variability in virus replication and pathogenicity of the three tested viruses in crickets at the two temperatures. In the infection study with bearded dragons, lizards inoculated with a Liz–CrIV did not become ill, but the virus was detected in numerous tissues by qPCR and was also isolated in cell culture from several tissues. Highest viral loads were measured in the gastro-intestinal organs and in the skin. These studies demonstrate that Liz–CrIV circulates in the pet trade in Europe. This virus is capable of infecting both invertebrates and poikilothermic vertebrates, although its involvement in disease in the latter has not been proven.

Virus Diversity and Loads in Crickets Reared for Feed: Implications for Husbandry

“…The fully identified insect-infecting viruses included IIV-6 (in the DNA fraction) and SBPV (in the RNA fraction). The IIV-6 reads matched the lizard strain of IIV-6, which infects both Orthopteran and reptilian hosts ( 28 ), and thus represents a direct potential health hazard for reptilian pets. The SBPV reads were closely related, though not identical, to the SBPV type strain ( 36 ).…”

“…For this we used two complementary approaches: a target-free exploration of cricket frass nucleic acid, for discovering new potential virus hazards, and a targeted screening of a limited set of insect and frass samples from several local Swedish cricket retailers and producers, for detecting and quantifying known viral pathogens of crickets. This targeted screening focused on nine different viruses, of which seven (Acheta domesticus densovirus -AdDV, invertebrate iridovirus 6 -IIV-6, Gryllus bimaculatus nudivirus -GbNV, Acheta domesticus volvovirus -AdVVV, Acheta domesticus mini ambidensovirus -AdMADV, Acheta domesticus virus -AdV and cricket paralysis dicistrovirus -CrPV) have been previously associated with the rearing of crickets (27)(28)(29)(30)(31)(32)(33)(34)(35). The remaining two viruses are slow bee paralysis virus [SBPV, (36)], which was present at high levels in the target-free nucleic acid exploration of the current study, and a novel Iflavirus recently characterized from wild A. domesticus (37).…”

Meta-Transcriptomic Discovery of a Divergent Circovirus and a Chaphamaparvovirus in Captive Reptiles with Proliferative Respiratory Syndrome

“…Despite their significance, our knowledge of reptile pathogens, particularly viruses, remains limited. Indeed, to date, the only viruses known to infect bearded dragons are double-strand DNA viruses from the families Iridoviridae [ 5 , 6 , 7 , 8 ] and Adenoviridae [ 9 , 10 ], single-stranded DNA viruses from the Parvoviridae [ 11 , 12 , 13 ] and RNA viruses from the Paramyxoviridae [ 14 , 15 ].…”

Identifikasi Interaksi Molekuler Peptida Antimikrobial dari Lendir Kulit Ikan Lele Kuning (Pelteobagrus fulvidraco) terhadap Penicillin-Binding Protein 3 (PBP3) pada Escherichia coli secara In silico

“…Selain itu, peptida tertentu juga berperan sebagai imunomodulator untuk meningkatkan imunitas tubuh (Gokhale & Satyanarayanajois, 2014). Hingga saat ini, sekitar 1200 PAM telah dikarakterisasi dan sebagian besar di antaranya diisolasi dari mamalia, amfibi, serangga, atau invertebrata lainnya (Papp & Marschang, 2019;Stöhr et al, 2016).…”