Schistosoma japonicum is a parasitic flatworm that causes schistosomiasis, a disease affecting millions of people, particularly in parts of Southeast Asia. The adult worms live in the blood vessels of their hosts, where they can produce eggs that may lead to severe health issues, including liver damage and gastrointestinal problems. The life cycle of S. japonicum involves freshwater snails as intermediate hosts. When humans come into contact with contaminated water, they can become infected through skin penetration by the larvae released by the snails. Effective control measures include improving sanitation and access to clean water to reduce transmission.