Which of the following correctly describes the transmission cycle of Schistosoma species, a type of helminth?

• A. Larvae are transmitted to humans through the bite of an infected mosquito.
• B. Eggs are released in human feces or urine, hatch in water, infect snails, and then cercariae penetrate human skin.
• C. Cysts are ingested from undercooked pork, develop into adults in the liver, and release eggs in bile.
• D. Eggs are ingested by humans from contaminated soil, hatch in the intestine, and larvae migrate to the lungs.

Answer: (B)

Verified step by step guidance

1. Identify the key stages in the life cycle of Schistosoma species, which is a parasitic helminth known for causing schistosomiasis.
2. Understand that Schistosoma eggs are released from infected humans through feces or urine into freshwater environments.
3. Recognize that these eggs hatch in water, releasing miracidia larvae that infect specific freshwater snails, which act as intermediate hosts.
4. Inside the snails, the larvae develop into cercariae, which are free-swimming and capable of penetrating human skin upon contact with contaminated water.
5. Conclude that the transmission cycle involves eggs released by humans, development in snails, and cercariae penetrating human skin, rather than transmission by mosquito bites, ingestion of cysts from pork, or ingestion of eggs from soil.