R.S. Ovchinnikov; M.G. Manoyan; A.N. Panin
The All-Russia State Center for Quality and Standardization of Animal Medicines and Feeds (VGNKI)
Etiologic agents of cutaneous infections in reptiles are attributed to a wide variety of non-dermatophytic fungi (J. Pare et al., 1997). It is often difficult to evaluate whether the isolated fungus is present as contaminant, or is involved in pathologic process. Thus, its clinical significance must be interpreted on the base of suitable diagnostic criteria. The aim of the study was to definite the occurrence and etiology of cutaneous mycoses in reptiles maintaining in captivity.
Twelve reptiles belonging to 8 species and presenting skin lesions were involved in this study. Clinical lesions consisted of scales, nodules, plaques, discoloration of the skin. Laboratory assay included direct microscopic examination, cultural assay and identification of isolated fungi. Clinical significance of cultured isolates was estimated according to Walsh-English criteria (A. Gupta et al., 2001). Susceptibility to antifungal agents was carried out using disc-diffusion method.
Fungal etiology of cutaneous lesions was established in 9 of 12 cases, in which fungal elements had been observed by direct examination. Darkly pigmented species were yielded in 4 of 9 positive samples: Alternaria alternata in turtle Agrionemys horsfieldii and iguana Iguana iguana, Phoma glomerata in chameleon Chameleo chameleon, Humicola spp. in gecko Hemitheconix caudicinctus. Fusarium moniliforme was isolated from 3 reptiles: python Phyton regius, iguana Iguana iguana and agama (Chlamidosaurus kingi). Iguana and agama were owned by the same collector. Both of them died suddenly in a few days after clinical evaluation. Cultures obtained from skin lesions and postmortem lung samples yielded the same fungus--Fusarium moniliforme. Thus, superficial lesions can reflect a course of a deep mycosis. In other 2 cases Penicillium chrysogenum fromturtle Trachemys scripta elagans and Mucor circinneloides from giant lizard Varanus brevicauda were isolated. Study of in vitro sensitivity to antifungal agents has showed that all tested fungi were resistant to azoles (clotrimazole, fluconazole, ketoconazole), but were partially inhibited by nystatin and terbinafine.
These results demonstrate high occurrence of mycotic lesions in exotic reptiles. All of them were caused by non-dermatophytic fungi, which can provoke lethal infections in some cases.
1. Pare J. et al., 1997. J. Zoo and wildlife med., 28(4), 443-453
2. Gupta A. et al., 2001. J. Clin. Microbiol., 39(6), 2115-2121