Protists and us
Like bacteria, protists are as useful to people as they are harmful.
When they help
- Acting as the primary producers of aquatic food chains.
- Joining with fungi to form the symbiotic association called a lichen.
- Producing the agar used to make media for culturing bacteria.
- Providing the alginic acid used in making ice cream.
When they harm
Some protozoa cause severe disease in people:
Amoebic dysentery
Malaria
Sleeping sickness
The first one is the biggest thing on the list
The ocean's food chain begins with algae. Which means every fish in the sea depends, in the end, on protists.
Amoebic dysentery, malaria and sleeping sickness are not bacterial diseases — they are protozoan ones, which is why antibiotics do not cure them.