Fungal community analyses in homes have been attracting attention because fungi are now generally considered to be allergens. Currently, these analyses are generally conducted using the culture method, although fungal communities in households often contain species that are difficult to culture. In contrast, next-generation sequencing (NGS) represents a comprehensive, labor- and time-saving approach that can facilitate species identification. However, the reliability of the NGS method has not been compared to that of the culture method. In this study, in an attempt to demonstrate the reliability of this application, we used the NGS method to target the internal transcribed spacer 1 (ITS1) in the fungal genome, conducted fungal community analyses for 18 house-dust samples and analyzed fungal community structures. The NGS method positively correlated with the culture method regarding the relative abundance of Aspergillus, Penicillium, Cladosporium and yeasts, which represent the major fungal components found in houses. Furthermore, several genera, such as Malassezia, could be sensitively detected. Our results imply that the reliability of the NGS method is comparable to that of the culture method and indicates that easily available databases may require modifications, including the removal of registrations that have not been sufficiently classified at the genus level.

To understand fungal contamination in the indoor environment of the disaster region, a field survey was performed to measure the number of fungal counts and identify isolates in the indoor air of prefabricated temporary housing, privately independent-housing, and rented apartments flooded by the East Japan Great Earthquake disaster tsunami. As a result, the period with the highest detected fungal count was from the rainy season to summer in independent-housing and rented apartments. Moreover, in the temporary housing, the fungal number increased further in winter as indicated by the maximum fungal-number throughout the measurement period. The detection frequency of Aspergillus species was relatively higher in the indoor air of temporary housing than in typical housing in the non-disaster area. Since Aspergillus is known as an allergenic genus, it requires careful attention to the health risk for residents. The extremely high level of fungal condensation in indoor air possibly occurred due to high relative humidity and loss of heat insulation in the building attics. It is suggested that this problem commonly happened in the cold region including the entire disaster region of the East Japan Great Earthquake.

Recently, the wild deer population has been increasing in Japan, causing serious feeding-related damage to the agricultural and forestry industries. In conjunction with the government's promotion of hunting for population control, the effective utilization of resources and promotion of the game meat industry as a sixth sector of industrialization are desired by local governments. However, several cases in which patients showed intestinal symptoms such as diarrhea due to the consumption of sika deer meat infected with protozoan Sarcocystis spp. have been reported, and the pathogenic microorganisms found in wild deer should be investigated. In this study, Sarcocystis sp. parasitized Kyushu sika deer ( Cervus nippon nippon ) in Nagasaki Prefecture, Japan, was examined for its enterotoxicity. A phylogenetic analysis based on the sequence of the 18S rRNA gene and cox1 showed that the species was highly homologous to Sarcocystis japonica and/or Sarcocystis sp. HM050622. We attempted to confirm the diarrhea-evoking toxicity of Sarcocystis sp. in sika deer meat, which has been previously reported in human case reports. A mouse ileal loop assay showed that Sarcocystis sp. in sika deer meat induced significant fluid accumulation in the loop at doses of ∼5 × 10 ⁶ bradyzoites. Western blotting showed that these Sarcocystis parasites possess actin-depolymerizing factor, a diarrhea-evoking factor, similar to Sarcocystis fayeri , which exists in horsemeat. However, the pathogenic conditions of the ileal loop were different from those of similar experiments with S. fayeri . This study suggests that S. japonica parasitizing C. n. nippon may cause diarrhea via a different mechanism from that of S. fayeri .

In recent years, the wild deer population in Japan has grown exponentially, causing severe feeding damage to the agricultural and forestry industries. Therefore, the game meat industry is being promoted for effective utilization of hunted animals. Wild animals are not hygienically controlled and can serve as reservoirs for pathogenic microorganisms. However, epidemiological information on wild animals in Japan remains insufficient. Recently, food poisoning-like cases have occurred because of raw venison infection with Sarcocystis spp. As the prevalence of Sarcocystis spp. in sika deer is very high in Japan and even fawns are infected, this study attempted to verify the vertical infection of Sarcocystis spp. in sika deer in Japan. Genetic detection of Sarcocystis 18S ribosomal RNA in fetal and maternal tissues from early to late gestation in sika deer revealed Sarcocystis Types 1–5 and Sarcocystis fayeri in the mother and fetus. Types 1, 2, 4, and 5 were detected in the maternal tissues of Ezo sika deer ( Cervus nippon yesoensis ) in Hokkaido, whereas Types 1 and 2 and S. fayeri were detected in fetuses. Types 1–5 were detected in Honshu sika deer ( Cervus nippon centrali s) in Mie Prefecture but not in the fetuses. Types 1, 2, and 4 were detected in the udder and milk samples. This indicates that Sarcocystis Types 1 and 2 and S. fayeri have the ability to pass through the placenta of sika deer and invade fetal tissues and Types 1, 2, and 4 may be transmitted orally via milk. These findings suggest that there is transplacental and transmammary transmission of Sarcocystis spp. in sika deer.

Recently, horse meat (basashi) contaminated with Sarcocystis spp. caused food poisoning in Japan. An official detection method provided by the Ministry of Health, Labour and Welfare (MHLW), Japan, was designed to detect Sarcocystis fayeri to diagnose and control outbreaks of basashi food poisoning. In 2011, Sarcocystis-contaminated venison also caused food poisoning. However, the official MHLW detection method was not adequate for detecting Sarcocystis spp. in venison. In this study, we established a novel PCR-based detection method that amplifies 18S rRNA gene based on the conserved region of the sequence in 32 species of Sarcocystis for screening and quantification. Fifty venison samples from three areas in Hokkaido were examined by the MHLW method and the novel detection method. All samples were Sarcocystis spp.-positive. A sequence analysis indicated the presence of a species of Sarcocystis specific to sika deer (Cervus nippon), and not to horses. Another primer pair was designed for a quantitative real-time PCR assay to determine the copy number of the Sarcocystis-18S rRNA gene in parasitized venison. The melting curve analysis revealed high specificity of this assay. The calculated curve demonstrated that this quantitative PCR assay showed R² value of 0.993 with 10–10⁶ copies. Using this quantitative real-time PCR assay, the gene copy numbers were determined in 50 venison samples. The copy numbers of each sample ranged from 10⁴ to 10⁷ per gram. The copy numbers differed according to the area in Hokkaido. This indicates that the density of Sarcocystis spp. that infect Sika deer in Hokkaido is affected by the area. The novel screening and quantitative PCR method for Sarcocystis in venison was useful for collecting epidemiological information on Sarcocystis in wild Japanese sika deer, which will contribute to improve the safety of venison products in Japan.

Objective: We investigated the prevalence of asthma, rhinitis, and atopic dermatitis in children, evaluated the mite allergen levels in their bedding after the Great East Japan Earthquake, and assessed changes in allergic symptoms in children and their families after allergen avoidance practices. Methods: We performed a survey for the International Study of Asthma and Allergies in Childhood (ISAAC) comprising 1109 children, aged 7–8 years, living in Ishinomaki, Japan. We collected responses from 464 children, and in 2016, measured the level of Dermatophagoides group 1 (Der 1) in the bedding of 202 of these children. The intervention group of children attended at least one allergen avoidance seminar. The levels of Der 1 in their bedding were measured, along with changes in allergic symptoms, in 17 children in 2017 and 14 children in 2018. The nonintervention group comprised children who did not attend an allergen avoidance seminar at any time. Results: Of the 464 children who participated in the ISAAC, 50 (10.8%) reported having asthma, 179 (38.8%) allergic rhinitis, and 126 (27.3%) atopic dermatitis. The average level of Der 1 measured in the bedding of the 202 children in 2016 was 295.8 ng/m2. The levels of Der 1 in the intervention group—but not in the nonintervention group—significantly decreased in 2017 and 2018. The symptoms of asthma, allergic rhinitis, and atopic dermatitis in the children of intervention group and their families decreased after allergen avoidance practices. Conclusions: Allergen avoidance practices relieved allergic symptoms in school children after the Great East Japan Earthquake.