protozoa

Protozoa are tiny, single-celled living organisms (microorganisms) that are usually found in water or moist places, and some of them can cause diseases in humans.

• What they are like: Protozoa are made of just one cell, but that one cell can do all life processes—moving, eating, growing, and reproducing.
• Where they live: Many protozoa live freely in ponds, lakes, soil, or inside other organisms. They often need a moist environment to survive.
• How they can cause disease: Disease-causing protozoa act as pathogens when they enter the body and multiply, damaging tissues or disturbing normal body functions.
• Common examples:
  • Plasmodium causes malaria (spread by female Anopheles mosquitoes).
  • Entamoeba histolytica can cause amoebic dysentery (often spread through contaminated food or water).
  • Giardia can cause diarrhoea (often linked to unsafe drinking water).
• Easy way to remember: Protozoa are “animal-like” microbes because many of them can move around and eat other tiny particles, unlike plants that make their own food.
• Important nuance: Not all protozoa are harmful—many are harmless and are simply part of natural ecosystems, especially in water bodies.