Sennetsu Fever is a rare infectious disease caused by the bacterium Neorickettsia sennetsu. It primarily affects individuals in Southeast Asia, particularly Japan. The exact mode of transmission is still unclear, but it is believed to be transmitted through ingestion of raw or undercooked fish. While the disease is contagious, it is not known to spread from person to person. Therefore, taking proper precautions such as cooking fish thoroughly can help prevent the transmission of Sennetsu Fever.