Aphanomyces infection in juvenile soft-shelled turtle, Pelodiscus sinensis, imported from Singapore

Abstract

Aphanomyces sp. was isolated from the carapaces of two juvenile soft-shelled turtles with fungal infections imported from Singapore. Their sizes were 2.9–3.5 cm in carapace length. Lesions with integumental necrosis and ulceration looked like white cotton. The fungus exhibited slow growth, hyphae were 7.5–15 μm in diam, coarse, and abundantly branched. Zoosporangia observed in the isolate were complex, its entire thallus being converted into zoosporangial units, with short or long lateral evacuation tubes, and isodiametric, 100–500 μm in length. Clusters of zoospores were also produced at the terminals of hyphae. The production of the primary zoospores was achlyoid. The primary encysted zoospores were spherical, 10–15 μm in diam. No sexual stages were observed on a hemp seed incubated in sterile tap water. The optimal temperature for the fungus was 30° C.