They will avoid areas where DO levels are below 3 mg/L, but generally do not begin to suffer fatalities due to oxygen depletion until levels fall below 2 mg/L 22. The mean DO levels should remain near 5.5 mg/L for optimum growth and survival Â¹Â².n a stable body of water with no stratification, dissolved oxygen will remain at 100% air saturation. 100% air saturation means that the water is holding as many dissolved gas molecules as it can in equilibrium.
Lesson Summary. 1  Most protist diseases in humans are caused by protozoa. 2  Protozoa make humans sick when they become human parasites. 3  Trypanosoma protozoa cause Chagas disease and sleeping sickness. 4  Giardia protozoa cause giardiasis, and Plasmodium protozoa cause malaria.esson Summary. 1  Most protist diseases in humans are caused by protozoa. 2  Protozoa make humans sick when they become human parasites. 3  Trypanosoma protozoa cause Chagas disease and sleeping sickness. 4  Giardia protozoa cause giardiasis, and Plasmodium protozoa cause malaria.
Primary Cause of Prion diseases. The primary cause of Prion diseases is the result: 1  of transmission from another person under rare circumstances, such as immunocompromised people or during surgery with contaminated surgical tools, or according to rare circumstances as noted from reputable sources.o research the causes of Prion diseases, consider researching the causes of these these diseases that may be similar, or associated with Prion diseases: 1  Spongioform encephalopathies. 2  Creutzfeldt Jakob disease. 3  Variant Creutzfeldt-Jakob disease. 4  Gerstmann Straussler Scheinker syndrome. 5  Fatal familial insomnia. 6  Kuru.