Seroprevalence of Antibodies Against Paracoccidioides Spp. in Captive Dolphins from Three Aquaria in Japan.

The skin disease paracoccidioidomycosis ceti occurs in several dolphin species globally. Infection by the unculturable fungi Paracoccidioides brasilensis or other Paracoccidioides spp. results in chronic cutaneous and granulomatous lesions. In this study we used immunohistochemistry to investigate the seroprevalence of antibodies to Paracoccidioides spp. in captive dolphins from three aquaria in Japan. We had previously reported that there were serological cross-reactions for Paracoccidioides spp. with related species in the order Onygenales. We hypothesized that the degree of serological cross-reactions for Paracoccidioides spp. might be lower in areas, such as Japan, where the fungal diseases coccidiodomycosis and paracoccidiodomycosis are not endemic. Sera from 41 apparently healthy dolphins, including 20 Atlantic bottlenose dolphins (BD: Tursiops truncatus), 6 Indo-Pacific bottlenose dolphins (IPBD: Tursiops aduncus), 2 F1 generation of a cross between BD and IPBD (F1), 3 Pacific white-sided dolphins (PWD: Lagenorhynchus obliquidens), 2 pantropical spotted dolphins (PSD: Stenella attenuata), 6 false killer whales (FKW: Pseudorca crassidens), and 2 rough-toothed dolphins (RTD: Steno bredanensis) were investigated. Sera from three dolphins with paracoccidioidomycosis ceti were used as a positive control. The yeast-form cells of Paracoccidioides spp. in the cutaneous tissue sample derived from the first Japanese paracoccidioidomycosis ceti case were used as the antigen for the immunohistochemistry. Of the 41 dolphins tested, 61.0% had antibodies against Paracoccidioides spp. This indicates that dolphins of several species in Japanese aquaria have likely been exposed to the pathogen Paracoccidioides spp.

Growth-related changes in histology and immunolocalization of steroid hormone receptors in gonads of the immature male green turtle (Chelonia mydas).

Studies on the population dynamics of sea turtles require histological evaluation of the ontogenetic development and the activity of the gonads for reproduction. To investigate the growth-related changes of gonads in the immature male green turtle (Chelonia mydas), the histological changes of testes and epididymides and the localization of the androgen receptor, estrogen receptor alpha, estrogen receptor beta, and progesterone receptor were examined. The testes were categorized histologically into six developmental stages, and a scarce relationship between straight carapace length and gonadal development was confirmed based on the histological analysis. Several kinds of steroid hormone receptors were examined to show distributions in both testes and epididymides, for which their immunoreactivities were enhanced according to the developmental stage of the testes. These results suggest that straight carapace length is not an adequate indicator of maturity determination, whereas histological and immunohistochemical evaluations are useful in identifying the growth stages of green turtles, owing to the higher sensitivity to steroid hormones that appear during growth.