Schistosoma is transmitted by –
**Core Concept**
Schistosomiasis, also known as snail fever, is a chronic and debilitating disease caused by parasitic flatworms of the genus Schistosoma. The transmission of Schistosoma involves a complex life cycle involving both aquatic and terrestrial environments.
**Why the Correct Answer is Right**
The correct answer is **C. Freshwater contaminated with Schistosoma cercariae**. Schistosoma cercariae are the larval stage of the parasite that infect humans through contact with contaminated water. When an individual comes into contact with infested water, the cercariae penetrate the skin, causing an allergic reaction and leading to the establishment of the infection. The cercariae then mature into adult worms, which reside in the bloodstream and eventually cause damage to the host's organs, including the liver, intestines, and bladder.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because Schistosoma is not typically transmitted through contaminated soil or feces. While contaminated water is the primary mode of transmission, feces can contain eggs that can contaminate water sources, perpetuating the cycle.
**Option B:** This option is incorrect because Schistosoma is not typically transmitted through the air or through direct contact with an infected individual. The parasite requires a specific aquatic environment to complete its life cycle.
**Clinical Pearl / High-Yield Fact**
It's essential to note that Schistosoma transmission can be prevented through proper hygiene practices, such as avoiding contact with contaminated water and wearing protective clothing. In endemic areas, treatment with antiparasitic medication is often necessary to control the spread of the disease.
**Correct Answer: C. Freshwater contaminated with Schistosoma cercariae**