Which of the following protozoan causes African sleeping sickness

The correct option is Trypanosoma gambiense.

Step-by-Step Explanation:

1. Understanding African Sleeping Sickness:
African sleeping sickness, also known as Human African Trypanosomiasis (HAT), is a vector-borne parasitic disease. It is caused by infection with protozoan parasites belonging to the genus Trypanosoma, which are transmitted to humans through the bites of infected tsetse flies (genus Glossina).

2. Identifying the Pathogen:
There are two subspecies of the parasite that infect humans:
- Trypanosoma brucei gambiense (often referred to as Trypanosoma gambiense) is responsible for the chronic form of West African sleeping sickness, accounting for over 98% of all reported cases.
- Trypanosoma brucei rhodesiense is responsible for the acute form of East African sleeping sickness.

3. Analyzing the Other Options:
- Plasmodium vivax: This is a protozoan parasite that causes malaria in humans, transmitted by the bite of an infected female Anopheles mosquito.
- Entamoeba gingivalis: This is an amoeba that resides in the oral cavity (mouth) of humans, primarily associated with periodontal disease and poor oral hygiene, and is not related to sleeping sickness.
- Trypanosoma lewisi (spelled lewsii in the options): This is a parasite of rats and is generally considered non-pathogenic to humans.