Protozoa are a diverse group of unicellular eukaryotic organisms, many of which are PROTOZOAmotile. Originally, protozoa had been defined as unicellular protists with animal-like behavior, e.g. movement. Protozoa were regarded as the partner group of protists to protophyta, which have plant-like behaviour, e.g. photosynthesis

In general, protozoa are referred to as animal-like protists because of movement (motile)
Protozoa commonly range from 10 to 52 micrometers, but can grow as large as 1 mm, and are seen easily by microscope. The largest protozoa known are the deep-sea dwelling xenophyophores, which can grow up to 20 cm in diameter. They were considered formerly to be part of the protista family. Protozoa exist throughout aqueous environments and soil, occupying a range of trophic levels

Some protozoa have life stages alternating between proliferative stages (e.g. trophozoites) and dormant cysts. As cysts, protozoa can survive harsh conditions, such as exposure to extreme temperatures or harmful chemicals, or long periods without access to nutrients, water, or oxygen for a period of time. Being a cyst enables parasitic species to survive outside of a host, and allows their transmission from one host to another

  • Malaria
  • Amoebiasis
  • Giardiasis
  • Toxoplasmosis
  • Cryptosporidiosis
  • Trichomoniasis
  • Chagas disease
  • Leishmaniasis
  • Sleeping Sickness
  • Dysentery