Among infectious diseases caused by pathogenic microorganisms such as viruses and bacteria, we are studying zoonoses, which are infectious diseases between animals and humans. In recent years, with the increasing distance between animals and humans and the improvement of diagnostic techniques for pathogenic microorganisms, it has become clear that a variety of zoonoses exist in the world and pose a significant threat to us and human society. Our research contributes to the prevention and control of these zoonotic diseases by clarifying how these pathogenic microorganisms are actually maintained in the field and the degree of risk they pose to humans and animals. We also conduct molecular biological studies using actual pathogens and various types of cultured cells to evaluate pathogenicity and elucidate the mechanisms of pathogen transmission.