Tell us about the lifestyle of the simplest parasites you know.

Trypanosome
Trypanosome is a unicellular organism, a bacterium belonging to the triposomatid family. It leads an exclusively parasitic lifestyle – it does not occur in nature as an independent microorganism. The vectors are insects – tsetse fly, triatomaceous bugs, female horseflies Tabanus and stomoxis flies. Trypanosomes of different types cause different diseases – sleeping sickness, Chagas disease, equine-hoofed juvenile disease, su-aura or trypanosomiasis of artiodactyls.
Trypanosome is a dangerous parasite: having settled in any organ of the mammalian body, it completely destroys it, causing the corresponding symptoms.
Leishmania
The disease is caused by leishmaniasis. Infection occurs through an “intermediary”. For example, a mosquito that has bitten a sick animal absorbs Leishmania promastigote along with the blood. When an infected female mosquito bites a human, she has to regurgitate some of the contents that fill her esophagus. Thus, promastigotes enter the victim’s blood.
Giardia
Giardia (Lamblia intestinalis) are very small parasites (on average 18 microns), they live in two life forms – trophosiod (vegetative stage) and cysts. The vegetative form is pathogenic and invasive – capable of infection, it is this form of life that causes symptoms in humans, because in this cycle the pathogen has a suction disc on the lower surface of the body, with the help of it it attaches to the wall of the small intestine and begins its parasitic lifestyle …
The disease caused by lamblia is called giardiasis. A person is considered a carrier of infection if there is giardia in him, but no symptoms of their presence arise.