Pilot survey reveals ophidiomycosis in dice snakes Natrix tessellata from Lake Garda, Italy

Abstract

Ophidiomycosis is an emerging infectious disease caused by the fungus Ophidiomyces ophidiicola (Oo). To date, Oo presence or associated disease condition has been recorded in wild and/or captive snakes from North America, Europe, Asia and Australia, but the data is still scarce outside the Nearctic. Although Italy is a country with a high snake biodiversity in the European panorama, and animals with clinical signs compatible with Oo infection have been documented, to date no investigations have reported the disease in the wild. Therefore, a pilot survey for the Italian territory was performed in conjunction with setting up a complete diagnostic workflow including SYBR Green-based real-time PCR assay for the detection of Oo genomic and mitochondrial DNA combined with histopathology of scale clips. Oo presence was investigated in 17 wild snake specimens from four different species. Four snakes were sampled in a targeted location where the mycosis was suspected via citizen science communications (i.e. North of the Lake Garda), whereas other ophidians were collected following opportunistic sampling. Oo genomic and mitochondrial DNA were detected and sequenced from all four Lake Garda Natrix tessellata, including three juveniles with macroscopic signs such as discolouration and skin crusts. From histopathological examination of scale clips, the three young positive individuals exhibited ulceration, inflammation and intralesional hyphae consistent with Oo infection, and two of them also showed the presence of arthroconidial tufts and solitary cylindrical arthrospores, allowing “Ophidiomycosis and Oo shedder” categorisation. For the remaining snake samples, the real-time PCR tested negative for Oo. This pilot survey permitted to localise for the first time Oo infection in free-ranging ophidians from Italy. Ophidiomycosis from Lake Garda highlights the need to increase sampling efforts in this area as well as in other northern Italian lakes to assess the occurrence of the pathogen, possible risk factors of the infection, its impact on host population fitness and the disease ecology of Oo in European snakes.

The Endangered Sardinian Grass Snake: Distribution Update, Bioclimatic Niche Modelling, Dorsal Pattern Characterisation, and Literature Review

“…Recently, the European Food Safety Authority’s funder project “AMPHIDEB” aims to develop biologically-based models for environmental risk assessment and to assess the impact of chemicals and pathogenic fungi on amphibian and reptile populations (see [ 125 ]). In this context, individuals of N. h. cetti are being monitored for ophidiomycosis, an emerging infectious disease caused by an ascomycete fungus (see [ 126 ]) whose presence has recently been ascertained in Italy, involving the genus Natrix [ 127 ].…”

Parasites and microorganisms associated with the snakes collected for the “festa Dei serpari” in Cocullo, Italy

“…In the same context, the introduction of exotic parasites (e.g., Renifer aniarum ) in grass snakes ( Natrix natrix ) and of snake fungal disease (SFD) caused by O . ophidiicola in dice snakes ( Natrix tessellata ) stresses the importance of monitoring the health status of wild populations of animals by accurate risk assessment [ 26 – 28 ]. In addition, aside from salmonellosis [ 29 , 30 ], zoonotic parasites of reptiles [ 16 , 31 ], including Reptile Vector-Borne diseases (RVBDs; [ 32 ]) have gained interest of the scientific community.…”

Characterisation, prevalence and severity of skin lesions caused by ophidiomycosis in a population of wild snakes

“…Increased interest in wild reptile health led to the detection of ophidiomycosis in wild snakes in Europe 13 , and subsequently in Asia 14 , 15 . The disease has been diagnosed in three species of the genus Natrix : the barred grass snake ( Natrix helvetica ) in southern and central England 13 ; the dice snake ( N. tessellata ) in the Czech Republic, Germany and Italy 13 , 16 , 17 ; and the European grass snake ( N. natrix ) in Switzerland 18 . Clinical signs of the disease have also been observed in a European grass snake ( N. natrix ) from Italy 18 .…”