Experimental Exposure of Canadian Toads to Basidiobolus Ranarum

Abstract

Experimental transmission of the fungus Basidiobolus ranarum was induced in two treatment groups of Canadian toads (Bufo hemiophrys) and caused a fatal mycotic dermatitis. Seven of 10 (70%) toads that had their ventral skin mildly abraded and exposed to B. ranarum developed hyperemia, and sloughing of their ventral skin and died. Toads with abraded ventral skin or exposure to infected skin also were affected statistically at a higher rate than those with abraded skin and exposure to pure cultures of B. ranarum innoculated into their water source. Of toads showing clinical disease, B. ranarum was identified by both impression smears and histology in all cases, but not from toads that appeared clinically healthy. The organism was cultured from 5 of 7 (71%) toads with clinical disease but not from any toad that appeared clinically healthy (n ϭ 28). This study documents methods of experimental transmission of B. ranarum, an organism responsible for causing a mycotic dermatitis that is fatal to toads.

Human Pathogenic Entomophthorales

“…If the conditions of moisture and soil organic matter are appropriate, the spores develop a coenocytic germ tube, and the cycle in nature is reinitiated (see above). There is at least one report of B. ranarum causing mortality in Canadian toads (Bufo hemiophrys) due to extensive dermatitis (118). Humans can be exposed to Basidiobolus propagules through open skin and contact with amphibian and lizard droppings, organic matter, insect bites, contaminated food, and soil containing the propagules of these fungi ( Fig.…”

“…In addition, Choon et al (171) suggested that chronic lymphedema could also play a role in the facial deformity observed in extreme chronic cases of rhinoconidiobolomycosis (118,130). According to the CLFLCV hypothesis, long-standing lymphostasis could induce permanent tissue overgrowth, as in elephantiasis cases (130).…”

“…Infections with C. coronatus commonly affect the subcutaneous tissues of the face (3,31,32,164,167). Good examples of this anatomical preference came from early studies of patients with rhinofacial swelling, and it was soon evident that this particular species has a strong tropism for subcutaneous tissues of the face (2,45,118,167,169). Rhinoconidiobolomycosis is typically caused by C. coronatus and starts with painless swelling around the soft tissues of the nose, slowly (weeks) extending to include adjacent tissue (44,45,174).…”

“…This stage includes rhinitis, intermittent episodes of epistaxis, sinus pain, and mild swelling of the infected areas (Fig. 11A) (118,130,167,169). (iii) "Intermediate disease" involves cases with 1 or more months of infection and coryza, epistaxis, nasal obstruction, noticeable reddishness, and swelling of the nose and nearby tissue, including enlarged lymph nodes (130).…”

Is the Chytrid Fungus Really Responsible for Amphibian Decline?~!2008-08-02~!2009-03-17~!2009-04-21~!

“…The chytrid fungus, Batrachochytrium dendrobatidis, has been associated with recent amphibian die-offs [2,[4][5][6][7][8]. A second fungus, Basidiobolus ranarum, has been isolated from clinically ill individuals from declining populations of Bufo baxteri [9][10][11][12][13]. A third pathogen is an iridovirus, a lethal virus from the tiger salamander Ambystoma tigrinum stebbinsi [14,15].…”