[show abstract][hide abstract] ABSTRACT: Sixty-six new and used samples of horse bedding materials: 60 rice straws, 2 wheat straws, 2 timothy hays and 2 wood chips, were collected from horse breeding stables of 33 farms in Japan and examined for the presence of Emericella nidulans (E. nidulans; anam. Aspergillus nidulans). The incidence of E. nidulans in the bedding materials was 75.8% and there was no significant difference in detection of the fungus between the new and used materials (25 out of the 33 samples, respectively). The growth of E. nidulans isolated in sterilized rice straw culture was accelerated by the addition of water up to about Aw 0.94, which as determined to be the most favorable moisture content. The addition of 0.3% urea solution onto the sterilized rice straw culture also appeared to very effectively enhance its conidial and ascocarp formation. A significant influence of urea on conidial and ascocarp formation of E. nidulans isolates was confirmed by their cultures on a synthetic medium which had urea as the sole nitrogen. These results suggest that severe contamination of E. nidulans on new bedding materials can be hazardous and its proliferation can readily occur at the stable due to the enhancing effect of urine. This analysis is meaningful to elucidate a reservoir of E. nidulans as the causative agent of guttural pouch mycosis in horses.
[show abstract][hide abstract] ABSTRACT: Seven strains of Emericella nidulans were isolated from lesions in the guttural pouch of horses with mycosis of this pouch. All strains grew in a wide range of temperature, pH and in five kinds of culture media. The optimum temperature that supported their growth was 38 degrees C, and all seemed to prefer an acidic environment with a pH of 4.0. Proliferative conidial formation was found to be induced by the aforementioned temperature and pH. Moreover, detection of beta-haemolysis and protease production suggested that these strains are biologically and biochemically active, which may imply that they have a potent pathogenicity of their own. Characteristics of two other strains of E. nidulans isolated from fomites were the same as those isolated from the infected horses. These findings suggest that E. nidulans is a potentially pathogenic to horses.
[show abstract][hide abstract] ABSTRACT: This paper describes onychomycosis in horses and reports the pathological findings, associated fungi and incidence of concurrent white line disease. In addition to these observations, relevance between post mortem and clinical findings of onychomycosis are discussed in 3 necropsied horses. Samples were collected from 100 hooves from a total of 51 Thoroughbreds suffering from white line disease. Of these, 15 hooves from 13 horses were also complicated with severe hoof wall fissure formation. Preparations from the same samples were used both for histopathology and for culture to identify the associated fungi. Onychomycosis was diagnosed when it could be confirmed histologically. Fungal identification was based on morphological characteristics in culture and the associated fungi were determined by comparison with culture morphology. As a result, 10 samples collected from horses were diagnosed as suffering from onychomycosis. Seven of these showed complicating severe inner hoof wall fissures and the soil fungus Scedosporium apiospermum or the teleomorph of this fungus, i.e., Pseudallescheria boydii, was isolated. The fungus was found to be ubiquitous in the fissure cavities, the terminal horn of the white line and the terminal horn-like laminae of the metaplastic white line-like tissue. It can be concluded that onychomycosis frequently causes white line disease and/or makes it worse. Associated with deterioration of the submural condition, the main associated fungus for onychomycosis in this series, was Genus Scedosporium and the most susceptible region was the terminal horn of the hypertrophied white line and/or the terminal horn-like laminae of the metaplastic white line-like tissue.
[show abstract][hide abstract] ABSTRACT: The hooves of a racehorse which were affected with white line disease and hoof wall disorders on both forelimbs were histopathologically investigated using thin ground section and standard paraffin section techniques. On both hooves, large quantities of fungus were found to have invaded the white line tissues, especially in the terminal horn which were markedly damaged. The fungus was also present among the cellular debris in the fissures of horny tissues. The morphological characteristics of the fungus were brown (its natural color), PAS-positive, mold-like shape with septa inside the tissues, and unicellular spores outside the tissues. These findings suggest that onychomycosis was a primary and/or secondary cause of white line disease in this subject.
Journal of Veterinary Medical Science 12/1996; 58(11):1117-20. · 0.88 Impact Factor