Bilharzia, also known as schistosomiasis, is caused by a parasitic worm that thrives in fresh water in subtropical and tropical regions.
Understanding the Cause in Detail
The root cause of bilharzia is infection by parasitic worms of the Schistosoma genus. These worms live in fresh water sources, particularly in areas with poor sanitation.
Where is Bilharzia Found?
According to the reference, bilharzia is most commonly found throughout Africa, but also lives in parts of:
- South America
- The Caribbean
- The Middle East
- Asia
How Does the Parasite Infect Humans?
The Schistosoma worms infect humans when they come into contact with contaminated fresh water. The worms penetrate the skin and migrate through the body, eventually residing in blood vessels near the intestines or bladder.
Life Cycle and Transmission
Understanding the life cycle of the parasite clarifies how humans become infected:
- Eggs are released: Infected individuals release Schistosoma eggs through their urine or feces.
- Eggs hatch in water: If these eggs reach fresh water, they hatch and release larvae called miracidia.
- Miracidia infect snails: Miracidia infect specific types of freshwater snails.
- Cercariae are released: Inside the snail, the parasites develop into another larval form called cercariae. These cercariae are released from the snail back into the water.
- Human infection: Cercariae can penetrate the skin of humans who come into contact with contaminated water.
- Maturation and reproduction: Once inside the human body, the cercariae mature into adult worms, which then reproduce and lay eggs, continuing the cycle.
Summary
| Cause | Explanation | Location |
|---|---|---|
| Parasitic Worms | Infection by Schistosoma worms. | Freshwater in subtropical and tropical regions, especially Africa, South America, the Caribbean, etc. |
| Contaminated Water | Contact with fresh water containing cercariae (larval form of the worm). | Lakes, rivers, and irrigation canals. |
