Rhinosporidiosis in African reed frogs Hyperolius spp. caused by a new species of Rhinosporidium

Abstract

We report the identification of a new Rhinosporidium species (Dermocystida, Mesomy ce tozoea) infecting amphibian hosts, while showing a species specificity for African reed frogs of the genus Hyperolius. Large dermal cysts (sporangia) of R. rwandae sp. nov. were observed in 18% of H. lateralis and similar cysts in 0.7% of H. viridiflavus surveyed. Fully developed R. rwandae cysts are about 500 to 600 µm in diameter and sealed from the frog tissue by a thick chitinous wall. Some cysts were filled with numerous round-oval basophilic microspores of 8 to 12 µm diameter. With the exception of legs, nodules were visible over the complete torso surface including the vocal sac of males, but the most affected skin region was the area around the cloaca. Behavior, condition, and lifespan of infected frogs do not seem to be distinct from that of healthy individuals. The mode of infection remains unknown, but we hypothesize that the infectious life stage reaches the dermis via the intraepidermal ducts of the skin glands. Molecular evidence places the new frog pathogen as a sister species of the human pathogen R. seeberi.

Characterization ofDermothecasp. Infection in a midwestern state-endangered salamander (Ambystoma platineum) and a co-occurring common species (Ambystoma texanum)

“…Dermocystidium penneri lesions are large (4–6 m m ) and range in shape from round to oval to serpiginous tracts of divided chambers (Jay and Pohley, 1981; Feldman et al ., 2005). Sphaerothecum caipira, Dermosporidium hylarum and Valentines rwandae all produce variably colored, 0.5–1 m m round lesions with or without ulceration (Carini, 1940; Borteiro et al ., 2014; Scheid et al ., 2015; Borteiro et al ., 2018 a ). Elongated, curved and dumbbell-shaped lesions have not been reported for these three dermocystid species.…”

“…The dorsal trunk is most commonly affected by S. caipira. V. rwandae , and D. pusula , and the ventral trunk by A. ranae, D. viridescens and D. penneri infections (Moral, 1913; Broz and Privora, 1952; Jay and Pohley, 1981; Pascolini et al ., 2003; Feldman et al ., 2005; Pereira et al ., 2005; Raffel et al ., 2008; González-Hernández et al ., 2010; Scheid et al ., 2015; Fiegna et al ., 2017; Borteiro et al ., 2018 a ). The head is a common site for lesion development in S. caipira and V. rwandae infections, the limbs are frequently affected by A. ranae and D. pusula , and the tail often hosts nodules in D. viridescens and D. pusula infections (Moral 1913; Guyénot and Naville, 1922; Raffel et al ., 2008; González-Hernández et al ., 2010; Fiegna et al ., 2017; Borteiro et al ., 2018 a ).…”

“…infection in ambystomatid salamanders from Illinois are generally consistent with those of other dermocystid parasites. However, these characteristics alone are inadequate for species identification within this group, and more recent classifications have relied upon molecular phylogenetics instead (Pascolini et al ., 2003; Feldman et al ., 2005; Pereira et al ., 2005; Raffel et al ., 2008; González-Hernández et al ., 2010; Scheid et al ., 2015; Fiegna et al ., 2017; Borteiro et al ., 2018 a ). These analyses have resulted in multiple species reclassifications and their placement within several new genera, with the most recent report proposing a major taxonomic restructuring to ensure monophyly within each genus (Borteiro et al ., 2018 a ).…”

“…Furthermore, dermocystid prevalence can vary between sympatric species examined within a single sampling period. Scheid et al (2015) examined 16 anuran species within the same swamp and detected V. rwandae in only two species, one of which (Hyperolius lateralis) had a much higher dermocystid prevalence (18.2%) than the other (H. viridiflavus, 0.7%). Prevalence of A. ranae was significantly higher in a population of declining R. lessonae (45.5-52.4%) than a stable population of R. esculenta (14.3-17.2%) from the same wetland complex in Italy (Pascolini et al, 2003).…”

Amphibians of Rwanda: Diversity, Community Features, and Conservation Status

“…Furthermore, some recent phylogenetic studies, which comprised species from the Albertine Rift used samples from Rwanda [64][65][66][67][68][69][70][71][72][73][74][75]. Our own contributions published so far have focused on amphibian communities in anthropogenically altered habitats [76][77][78][79], studies on the taxonomy and ecology of the genera Hyperolius [58,62,[80][81][82][83][84][85], Afrixalus [86,87], and Ptychadena [88][89][90], and amphibian parasites [91][92][93][94][95].…”