Final answer:
Trypanosoma brucei is the parasitic infection responsible for African sleeping sickness, which eludes the immune response by changing its surface proteins and is transmitted through tsetse fly bites.
Step-by-step explanation:
Trypanosoma brucei is responsible for African sleeping sickness and is considered a parasitic infection. This organism is known for its ability to evade the human immune system by frequently changing its thick layer of surface glycoproteins, making it a complex pathogen to combat. Each glycoprotein variation represents a different antigen, causing the immune system to mount a response that becomes ineffective when the Trypanosome switches its surface proteins in subsequent generations. Humans can contract this parasite through the bite of an infected tsetse fly, which transmits the Brucei protozoa. The disease progresses from systemic symptoms to neurological involvement leading to severe conditions such as coma or death if left untreated, highlighting the necessity of control measures and proper treatment.