Phaeohyphomycotic dermatitis in a giant panda (Ailuropoda melanoleuca) caused by Cladosporium cladosporioides
The giant panda was an 18-year-old male, who lived in a semi-captive and semi-stocking environment at the Giant Panda Protection Research Center. The center is located in Ya'an, a humid, mountainous area in southwest China. A small amount of hair loss was observed at the dorsum nasi of the giant panda and the skin of the dorsum nasi was scratched by its front paws. The dermatic lesion on its dorsum nasi was measured as 12 cm×8 cm (). The skin lesion, which was initially hard, erythematous and displayed edema, later became pruritic. Skin scrapings were examined using a microscope and fungal spores were identified. The identification of these symptoms was defined as day 0.\nFive days after the symptoms were identified, the giant panda was first treated with antimycotic ketoconazole (600 mg/day orally), and the treatment regimen continued for 2 months. The skin redness disappeared and hair loss was recovered.\nHowever, the same symptoms recurred 3 months after the ketoconazole treatment stopped. The same treatment was reinitiated but the giant panda was not responsive to the second treatment with ketoconazole. Samples of the secretion, furfurescence, thrix and hair follicles of the dorsum nasi were collected. The samples were cultured on Sabouraud's dextrose agar (SDA) at 25 °C for 2 weeks. Black colonies were observed on the agar and the colony discs were subsequently cultured on potato dextrose agar (PDA) at 25 °C. After 48 h, yellowish-green colonies had formed and were approximately 1.0 cm in diameter. After 5 days, the colonies gradually turned black and were about 5 cm in diameter. The fungus grew well on SDA at 25–28 °C, grew poorly at 30 °C, and did not grow at 35 °C. Microscopic observation revealed that the fungus had long conidiophores with ellipsoidal conidia. The conidiophores were non-nodose and had both terminal and lateral ramifications ().\nPCR was performed to further identify the fungus. Genomic DNA was extracted and amplified using primers targeting internal transcribed spacer 1 (ITS1) and internal transcribed spacer 4 (ITS4). The resulting sequence of 509 nucleotides was subjected to a homology search using the BLAST alignment program of the GenBank database. The sequence was 99% identical to the C. cladosporioides gene, with a highest maximum score of 922 (GenBank accession number: JQ727688.1). The expected E value for the identity was 0.0, indicating that this result was non-random and statistically significant. The fungus was thus identified as C. cladosporioides. Oral itraconazole (700 mg daily) was administered. After 3 months of treatment, the edema disappeared and the infection was completely healed (). No reoccurrence was found one year after the recovery.