Aflatoxin produced by Aspergillus flavus is known to be strongly related to liver injury (hepatocellular carcinoma) and immune system damage involving leukocytes. This toxin suppresses both the cell-mediated immune system and macrophage function, and decreases the production of complement and interferon molecules. Purpose: To evaluate the presence of aflatoxin in infectious lesions as well as how the toxin is taken up by leukocytes. Method: Pathological specimens from a patient who died from aspergillosis caused by aflatoxin-producing A. flavus were used. Anti-aflatoxin B1 antibody was reacted with paraffin-embedded lesion specimens from the heart, kidney, and thyroid gland of the patient and observed microscopically. Result: Positive reactions were detected in fungal elements and leukocytes (neutrophils and macrophages) in inflammatory lesions. Conclusion: Within the patient's body, A. flavus likely produced aflatoxin, which then was taken up by neutrophils and macrophages. These results suggest that leukocyte function and the immune mechanism are locally suppressed by aflatoxin.
Rhizopus oryzae causes fatal invasive mucormycosis, especially in immunocompromised patients. Posaconazole is used to treat mucormycosis caused by R. oryzae, which is resistant to fluconazole and voriconazole. We evaluated the efficacy of posaconazole against R. oryzae in vivo using a silkworm infection model at 37℃, the human body temperature. The level of pathogenicity differed among the R. oryzae isolates, and posaconazole prolonged the survival of infected silkworms. Therefore, the silkworm infection model is suitable for investigating the virulence factors of R. oryzae and developing antifungal agents for mucormycosis.
To evaluate the role of companion birds as a reservoir of Encephalitozoon hellem infection in humans, the present study determined the prevalence and genotypes of E. hellem from 269 birds in 4 pet shops using polymerase chain reaction (PCR) assay. E. hellem was identified in 4.8% (13/269) of the birds and was detected in all pet shops. Every positive sample corresponded to zoonotic genotype 1A. Considering the low prevalence of E. hellem infection, it is likely that the risk of zoonotic transmission from companion birds kept in pet shops to humans is low in Japan.
Background: Dermoscopy is a new method to diagnose and manage nail disorders. The definite dermoscopic finding for onychomycosis, however, is still debatable. Objective: To identify the dermoscopic features that help differentiate between onychomycosis (OM) and traumatic onychodystrophy (TOD). Methods: A prospective study of 65 patients with toenail abnormalities was conducted. The patients were classified into OM and TOD groups using mycological tests (potassium hydroxide test, fungal culture, and histological examination). OM was diagnosed from positive results for all tests, while TOD was decided based on negative results for all tests and evidence of foot trauma. Dermoscopic features were recorded and compared between the two groups. Results: Most patients of the 65 patients were female (72.3%), and had a mean age of 67.9 years. Twenty-seven patients (41.5%) were diagnosed with OM, all of which were distal and lateral subungual onychomycosis. TOD, on the other hand, was determined in 38 patients. Dermoscopic findings revealed that the yellow, clumping, sulphur-nugget-like debris in the ruin appearance was significantly associated with onychomycosis (p = 0.002), while ruin appearance without sulphur nugget was not statistically correlated with onychomycosis (p = 0.068). Conclusion: The presence of sulphur nuggets in the ruin appearance is a new and helpful dermoscopic feature for onychomycosis diagnosis.