Emerging fungal pathogens of captive reptiles in the Russian Federation
Exotic reptiles have taken in a niche of popular companion animals in recent decades. However, the importance of fungal infections in reptiles is still underestimated in many cases. Mycoses in reptiles can be caused by a variety of fungal species. However, the leading role belongs to representatives of the genera Nannizziopsis, Paranannizziopsis, Ophidiomyces (Onygenales, Onygenaceae), which were previously treated as members of the anamorphic polyphyletic genus Chrysosporium. Here we present our data on the etiology of fungal infections in reptiles in Russia. Ninety-two samples from pet reptiles demonstrating skin lesions were examined mycologically, most samples (47%) from green iguanas (Iguana iguana). Totally, fungal etiology was confirmed in 79% of reptiles. The prevalent pathogen was identified by conventional methods as Chrysosporium anamorph of Nannizziopsis vriesii (37%). The ITS sequencing of typical isolates from green iguana revealed 100% homology with Nannizziopsis guarroi (GenBank accessions MN443762, MN443763). BBased on observations in the Moscow Zoo, the predisposed reptile species were green iguana (Iguana iguana) and bearded dragons (Pogona vitticeps). Moreover, mycoses caused by Chrysosporium-related fungi were diagnosed in reptile species Tiliqua scincoides, Lacerta lepida, Lacerta rudis, Sceloporus occidentalis, Homopus areolatus, Pelodiscus sinensis, and Varanus exanthematicus. Chrysosporium-related pathogens in these species had previously not been reported. In snakes, fungal infections have suddenly emerged in recent years. Ophidiomyces ophiodiicola is currently treated as the major pathogen of snake fungal disease (SFD) in wild and captive snakes. Recently we diagnosed three cases of O. ophiodiicola in file snakes Acrochordus granulatus imported into Russia from Indonesia. The identification was performed by ITS sequencing (GenBank accession MT271736). Snakes showed multiple bullous white vesicles filled with exudate. All three snakes died within a month after arrival. In conclusion, Onygenalean fungi have recently emerged as cardinal pathogens in captive reptiles. Pathogenic species N. guarroi and O. ophiodiicola were detected in Russia for the first time.