Kahori Koyama’s research while affiliated with Azabu University and other places

Introduction The One Health concept is a comprehensive understanding of the interaction between humans, animals, and the environment. The cohabitation of humans and pets positively affects their physical, mental, and social well-being. It is recognized as an essential factor from the One Health perspective. Furthermore, a healthy balance in the gut microbiome is essential for good health, and the changes in the gut microbiome associated with cohabitation between humans and pets could potentially affect various aspects of the health of both hosts. Therefore, elucidating the sharing of gut bacteria between humans and pets associated with cohabitation is important for understanding One Health. However, most studies have examined sharing at the taxonomic level, and it remains unclear whether the same bacteria are transferred between humans and pets, and whether they mutually influence each other. Methods Here, microbiome analysis and shared 16S rRNA gene amplicon sequence variant (ASV) analysis were conducted before the start of cohabitation between humans and dogs, as well as at 2 weeks, 1 month, and 3 months after cohabitation. Results 16S rRNA gene ASVs analysis indicated that gut microbes have been transferred between humans and dogs. The overall structure of the gut microbiota within human–dog pairs remained unchanged after 3 months of adaptation. However, 11ASVs were shared within human–dog pairs. Many shared ASVs were highly abundant within each host, and this high abundance may be considered a factor that influences bacterial transfer between hosts. Discussion Our results provide important insights into the potential for the transfer of gut bacteria between humans and dogs. These findings are considered crucial for understanding the impact of human–dog cohabitation on various aspects of health.

The sleep-wake cycle represents a crucial physiological process essential for maintaining homeostasis and promoting individual growth. In dogs, alterations in sleep patterns associated with age and dog’s correlation with temperament factors, such as nervousness, have been reported, and there is an increasing demand for precise monitoring of sleep and physical activity in dogs. The present study aims to develop an analysis method for measuring sleep-wake patterns and physical activity in dogs by utilizing an accelerometer and a smartphone. By analyzing time series data collected from the accelerometer attached to the dog's collar, a comprehensive sleep and activity analysis model was constructed. This model classified the activity level into seven classes and effectively highlighted the variations in sleep-activity patterns. Two classes with lower activity levels were considered as sleep, while other five levels were regarded as wake based on the rate of occurrence. This protocol of data acquisition and analysis provides a methodology that enables accurate and extended evaluation of both sleep and physical activity in dogs.

Introduction The One Health concept is a comprehensive understanding of the interaction between humans, animals, and the environment. The cohabitation of humans and dogs positively affects their physical, mental, and social well-being. It is recognized as an essential factor from the One Health perspective. Furthermore, a healthy balance in the gut microbiome is essential for good health, and the sharing of gut microbes between humans and dogs may positively impact the health of both hosts. Therefore, elucidating the sharing of gut bacteria between humans and dogs is important for understanding One Health. However, most studies have examined sharing at the taxonomic level, and it remains unclear whether the same bacteria are transferred between humans and dogs, and whether they mutually influence each other. Methods Here, microbiome analysis and 16S rRNA gene amplicon sequence variant (ASV) analysis was performed to address this question. Results 16S rRNA gene ASVs analysis indicated that gut microbes have been transferred between humans and dogs. The overall structure of the gut microbiota within human-dog pairs remained unchanged after three months of adaptation. However, some ASVs were shared within human-dog pairs. Many shared ASVs were highly abundant within each host, and this high abundance may be considered a factor that influences bacterial transfer between hosts. Discussion Our results demonstrate the possibility of the direct transfer of gut bacteria between humans and dogs, providing an important insight for achieving good health through human-dog cohabitation.

One out of every five people in Japan is dissatisfied with their sleep and various diseases caused by lack of exercise have been pointed out, but there are few effective remedies for these problems. In this study, we aimed to develop a simple method for measuring behavioral sleep patterns and physical activity using a beacon accelerometer wirelessly connected with a smartphone. A sleep prediction model was created comparing the data obtained from the accelerometer with the sleep status data obtained by a previously validated sleep monitoring system. The Random Forest model was able to classify sleep and wakefulness with a 97.4% and 85.4% precision, respectively, which were comparable to those of conventional acceleration-based sleep monitoring devices. Additionally, the same data acquisition method was used to classify exercise intensity into seven levels and a high correlation (r=0.813, p<0.0001) was found when comparing the classified exercise intensity to metabolic equivalent (MET) values. This suggests that the proposed method can be used for accurate measurement of both behavioral sleep and physical activity classifying over a long period of time.

Our research is canine guidance using spotlights. Using dogs' habit following light, a spotlight guidance suit can remotely guide dogs by switching spotlight irradiation. The problem was that the spotlight devices were long and could get caught in the dog's surrounding environment. In this study, we considered lenses with different focal lengths and shapes using an optical simulator to shorten the length of the spotlight devices. By using a short focal length and a plano-convex lens, we succeeded in shortening the spotlight device. In addition, we verified to guide canine outdoors using a spotlight guidance suit. The difficulty of outdoor guidance is that people and animals walk around the field, and their movements and sounds attract the dog's attention. Also, we examined whether the dog could follow the spotlights even in a bright outdoor environment. As a result, we succeeded in the outdoor navigation.