Trypanosomes are small unicellular organisms (approximately 30 microns in size) which are classified with the kinetoplastids, named as such because they have two flagella which they use to swim. These include species that live in both fresh and salt-water and also parasites such as the Trypanosomes and species belonging to the Leishmaniagenus.
Curiously, genetic analysis of the rRNA (ribosomal) has shown that these organisms are related to microscopic algae (capable of photosynthesis), the Euglena.
The Trypanosomes and Leishmania are mammal parasites transmitted by insects. In human beings the Trypanosomes cause trypanosomiasis (Chagas disease and sleeping sickness) and the Leishmania cause leishmaniasis.