The incidence of animal mycosis, especially sporotrichosis, histoplasmosis and other opportunistic fungal infections, has recently increased in Japan. It may partly due to changes in the environments of human and animal life and the more intimate relation between humans and animals. Exotic animals such as hamster, guineapig and rabbit have become a popular source of human dermatophytosis and some were imported from foreign countries followed by the emergence of fungal pathogens. Moreover, the number of cases of opportunistic deep mycotic infections have increased among old companion animals with the progress in veterinary medicine of chemotherapy, immunotherapy and prevention.
Therefore, the interrelation and cooperation of medical and veterinary doctors and all other scientists involved is required to prevent human and animal mycoses.

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Histoplasmosis is a fungal infection caused by Histoplasma capsulatum and is distributed a worldwide. Although the disease has been treated as an imported mycosis, some autochthonous human, 1 equine and 4 canine cases suggested that the disease is endemic. Histoplasmosis is classified depending on the variety of causative agent. Histoplasmosis farciminosi known as pseudofarcy, is manifested only in Perissodactyla where it invades lymph nodes and lymph ducts, and is recognized by isolation from horses. Historically, Japan was one of the endemic areas of pseudofarcy before World War II, and more than 20, 000 cases were recorded in horses used by the military. Interestingly, Japanese canine histoplasmosis uniformly showed skin ulcers and granulomatous lesions on the skin without pulmonary or gastrointestinal involvement, both of which were very similar to pseudofarcy. It was diagnosed as histoplasmosis by the detection of internal transcribed spacer legions of rRNA gene of H. capsulatum from paraffin embedded tissue samples. Furthermore, the fungal isolate from the human case with no history of going abroad or immigrating was identified as H. capsulatum var. farciminosum by a gene sequence. These facts indicated that pseudofarcy is not only an infectious disease in horses, but also a zoonotic fungal infection. Japanese autochthonous canine histoplasmosis might be a heteroecism of pseudofarcy because of its likeness to the human case, the similarity of clinical manifestations and the historical background at this stage.

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Microsporum canis, Trichophyton verrucosum and T. mentagrophytes are the most common dermatophytes isolated from human and animals. M. canis infection in human is closely related to companion animals such as cats and dogs. According to a recent epidemiological survey in Japan, human M. canis infection is decreasing. T. verrucosum is usually transmitted from cows to human. T. verrucosum infection in human is not restricted to daily farming prefectures, however, suggesting that this species has already been spread widely in Japan. T. mentagrophytes is one of the most common pathogens in human tinea. Recent molecular methods show the infection is caused by one teleomorph of T. mentagrophytes, Arthroderma benhamiae, which has already been spread throughout Japan by companion animals. This pathogen is believed not to have existed in Japan until 1980. The chance of human fungal infection caused by unusual pathogens is increasing because of the changes in types of companion animals. Animal dermatophytoses is now an important issue not only for veterinary doctors but also for dermatologists.

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Various mycotic zoonoses of human transmitted from animals have recently been viewed as a serious matter. The outbreaks of these diseases under many complicated circumstances occur in the community between human and animals. Cooperation is needed to prevent the expansion of infections of zoonoses by both human and veterinary medicine.

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Epidemiological studies on tinea pedis and onychomycosis have been performed across Europe and East Asia. The prevalence of these conditions was 20%, respectively, and it increased with advancing age, more men than women had fungal infection of the feet. The prevalent predisposing factors were sports participation, average temperature, and family history of tinea pedis. The predisposing diseases were hypercholesterolemia, cardiovascular disease, diabetes mellitus, and osteoarticular disease. We conducted an epidemiological investigation to determine the prevalence and circumstances of untreated and unsuspected tinea pedis and onychomycosis. The results showed that the prevalence of occult athlete's foot was 25%, and that 59% of those cases were complicated by tinea unguium. The characteristics of patients with occult athlete's foot included a higher proportion of men and a tendency toward a low clinical score together with a high severity score. In the patient background, a strong correlation was observed between a positive KOH test result and characteristics such as past history of tinea pedis and/or onychomycosis, age, disposition of toes, and predisposing disease, as well as the type of shoes worn daily. We suspected that a patient's local and systemic conditions affected each other, creating good conditions for tinea pedis and onychomycosis so that the prevalence has increased. More understanding of occult athlete's foot will lead to prevention and improvement in treatment and diagnosis.

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Dermatophytoses such as tinea pedis and tinea unguium are very common diseases in the field of dermatology. The diagnosis of dermatophytoses is usually performed by direct microscopy and culture. The identification of species is based on morphological features of giant culture and slide culture. However, in some cases, it is difficult to identify the species clearly because the culture shows an atypical appearance or is false negative. Therefore, several molecular biological methods have been developed for precise identification of a species. The analysis of patterns of random amplification of polymorphic DNA (RAPD) and restriction fragment length polymorphisms (RFLP) of mitochondrial DNA is useful for identifying isolates which are not clearly identifiable by conventional biological techniques. The phylogenetic analysis of dermatophytes was made by using DNA direct sequencing of nuclear ribosomal internal transcribed spacer 1 (ITS 1). Sequence analysis of chitin synthase 1 (CHS 1) is a rapid tool for species level identification.
We attempted the identification and viability assessment of dermatophytes based on the quantitative measurement of dermatophyte actin (ACT) mRNA. An internal fragment of the ACT, 725 to 762 bp, was isolated by PCR from the genomic DNA of dermatophytes and sequenced. ACT intron based primers were dermatophyte species-specific and primer pairs crossing the intron were dermatophyte genus-specific. The results indicated that quantification of dermatophyte ACT mRNA correlated with the results of culture and KOH examination.
It is important that the identification of dermatophyte be done by combining conventional methods with molecular biological methods. In some cases results of the two methods do not correspond, and is those the fungal species needs to be re-examined.

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Preventive measures against tinea pedis were discussed based on our mycological studies using foot-press method and house dust cultures. 1) Untreated patients with tinea pedis frequently disseminate pathogenic fungi into the environment, but dissemination could be easily controlled by simple application of antifungal agents. 2) A high proportion of dermatophytes disseminated in house dust perished naturally within a month under dry conditions, while under moist conditions they survived several months or more. Therefore, humid areas such as the floor and carpet of a bathroom should be cleaned or washed regularly. 3) Adhesion of dermatophytes onto healthy feet usually happens in public spaces where people enter without shoes. Wearing socks cannot prevent dermatophyte adhesion. Cleaning the feet by wiping with a towel or washing with soap seemed to be an effective prophylactic measure after stepping into such spaces.

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We evaluated the minimum time for penetration of Trichophyton mentagrophytes into human stratum corneum using an experimental model of tinea pedis. After fungal elements were applied on the surface of stratum corneum obtained from a healthy human heel, samples were incubated under designated conditions of temperature and humidity. The penetration of fungal elements was much faster at 35°C than 27°C despite the fact that the latter is an optimal temperature for fungal growth. At 35°C and 100% humidity the minimum time required for penetration was one day. When we applied fungal elements on an abraded surface of stratum corneum, fungi penetrated within a half day under the same conditions. This suggests that minor injury of stratum corneum is a significant factor for infection.
The development of tinea pedis does not occur frequently in daily life. We examined the effect of washing the surface of stratum corneum to which T. mentagrophytes had been applied. The samples were incubated under conditions simulating daily life: i. e. with 80% humidity for 8 hours, and 100% humidity for 16 hours. After washing, nearly all the fungal elements had been removed from the surface of stratum corneum within one day. The data suggests that to prevent tinea pedis, daily washing of soles and interdigital regions is effective.

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A delayed-type hypersensitivity (DTH) response to a dermatophyte antigen is one of the host defense mechanisms. Peripheral blood mononuclear cells from patients with dermatophytosis produce a high level of IFN-γ in response to stimulation with trichophytin. The presence of IFN-γ mRNA in skin lesions of dermatophytosis was detected using reverse transcription-polymerase chain reaction. IFN-γ-positive cells were observed immunohistochemically in the upper dermis of the skin lesions. These findings support the hypothesis that the skin lesions of dermatophytosis are associated with a Th1 response. The Th1 response, which is characterized by IFN-γ release, is thought to be involved in the host defense against dermatophytes and to reflect cutaneous reaction in dermatophytosis.
The stimulation of trichophytin significantly enhanced the release of IL-8 from keratinocytes. These findings account for the accumulation of neutrophils beneath the stratum corneum. The capacity of trichophytin-stimulated keratinocytes to release an enhanced level of IL-8 thus suggests that these cells can indeed help to induce the acute inflammatory response seen in dermatophyte infection. It therefore appears that keratinocytes not only play an important structural role in the formation of a physical barrier to dermatophytes but may also play an important functional role in initiating cutaneous inflammatory reactions, which might be involved in the host defense againt dermatophytes.
The production of IFN-γ by peripheral blood mononuclear cells from patients with tinea unguium in response to stimulation with trichophytin was not impaired in contrast to that from patients without tinea unguium. Comparable lymphocyte proliferation with trichophytin was observed in both groups. No deficiency in Th1 response to dermatophyte antigen was shown in patients with tinea unguium by measuring the release of IFN-γ, which plays a role in the effector phase of the DTH reaction. A deficiency of Th1 response to dermatophyte antigen, therefore, does not appear to play an important role in the establishment of tinea unguium.

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Recent trends of fungal infections of the ear, nose and throat were introduced from the viewpoint of otolaryngologic practice.
Aspergillus (A.) terreus was the most common pathogen of otomycosis followed by A. niger and A. flavus. Lanoconazole showed the most effective antifungal function for these A. species by drugsensitivity test. Biological differences between clinical and soil-borne strains of A. terreus were evaluated. The clinical strains showed slower growth-rate on malt extract agar and different patterns of fingerprinting by Random Amplified Polymorphic DNA.
Aspergillosis is the most common fungal disease in the paranasal sinuses. Unilateral opacity of the maxillary sinus which contains flecks of calcification was specifically found by CT-study. Surgical removal of the fungus ball and establishment of a drainage route to the nasal passage by endoscopic sinus surgery are effective to manage aspergillomas in paranasal sinuses.
Although candidosis is a common and mild infection in the oral mucosa, underlying problems related to immunodeficiency syndrome must be evaluated.

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The effects of 12 essential oils, popularly used as antifungal treatments in aromatherapy, on growth of Candida albicans were investigated. Mycelial growth of C. albicans, which is known to give the fungus the capacity to invade mucosal tissues, was inhibited in the medium containing 100μg/ml of the oils: lemongrass (Cymbopogon citratus), thyme (Thymus vulgaris), patchouli (Pogostemon cablin) and cedarwood (Cedrus atlantica). Not only lemongrass oil but also citral, a major component of lemongrass oil (80%), in the range of 25 and 200μg/ml inhibited the mycelial growth but allowed yeast-form growth. More than 200μg/ml of citral clearly inhibited both mycelial and yeast-form growth of C. albicans. These results provide experimental evidence suggesting the potential value of lemongrass oil for the treatment of oral or vaginal candidiasis.

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Cryptococcus neoformans is a pathogenic basidiomycete with a defined sexual cycle involving mating between haploid yeast cells with a transient diploid state. We examined F1 progeny from a crossing between the urease-negative strain (environmental isolate, serotype A, mating type α, haploid) and a tester strain (B 3502 from NIH of USA; urease-positive, serotype D, mating type a, haploid) for serotype, mating type, ploidy and urease activity, and performed partial sequencing of the urease gene. Phenotypes of the F1 progeny and results of SSCP analyses suggested that the serotype AD strain of the F1 progeny is a hybrid of the parental serotype A and D strains.

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A strain of Histoplasma capsulatum var. duboisii (deposited as IFM 50954 in Chiba University) was isolated from the cerebrospinal fluid of a female Ugandan patient infected with HIV. The isolate had in vitro urease activity on Christensen's urea agar slants, although the common belief is that H. capsulatum var. duboisii is urease negative, and is, considered one of the characteristic markers that distinguishes the three varieties of H. capsulatum. Forty H. capsulatum var. capsulatum, five H. capsulatum var. duboisii, and five H. capsulatum var. farciminosum isolates were evaluated for urease activity on Christensen's urea agar slants and for other qualitative and quantitative urease assays of activity. All 50 isolates of H. capsulatum used in this study were positive for urease activity, suggesting that urease activity may be universal characteristic of H. capsulatum. We also compared the urease activity and pathogenicity of seven H. capsulatum isolates that convert into yeast-form cells. Although isolate IFM 50954 showed moderate virulence in mice and moderate urease activity among tested H. capsulatum isolates, there was no correlation between level of urease activity and pathogenicity. In addition, scanning electron microscopy revealed that some microconidia of isolate IFM 50954 formed “double-cell” configurations that were attached to each other by narrow bases.

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