Sleeping sickness is caused by?

ESIC Nursing Officer 2016 (shift-1)

Applied Microbiology & Infection control

Easy

Appeared in: ESIC Nursing Officer 2016 (shift-1)

Explanation

Sleeping sickness, or African Trypanosomiasis, is exclusively transmitted by the bite of infected tsetse flies of the genus Glossina.
The tsetse fly injects the protozoan parasite Trypanosoma brucei into the host during a blood meal.
There are two main subspecies of the parasite: T.b. gambiense (West/Central Africa, chronic) and T.b. rhodesiense (East/Southern Africa, acute), both transmitted by tsetse flies.
The geographic distribution of the disease is limited to sub-Saharan Africa, corresponding to the habitat of the tsetse fly, often called the 'fly belt'.

Option A: Mosquitoes are vectors for numerous viral and parasitic diseases, but not for African sleeping sickness.
Option B: House flies are mechanical vectors, meaning they transfer pathogens by contact (e.g., landing on feces then food), rather than through a bite.
Option D: Sand flies are the specific vectors for a different group of protozoan parasites, the Leishmania species.

Visual 1: Image - A close-up photograph of a Tsetse fly (Glossina) highlighting its distinct features, such as the forward-pointing proboscis and unique wing folding pattern (overlapping like scissors at rest). This helps in visual identification.
Visual 2: Map - A map of Africa showing the 'tsetse belt' to illustrate the geographical areas where sleeping sickness is endemic.
Visual 3: Diagram - The life cycle of Trypanosoma brucei, showing the stages in both the human host and the tsetse fly vector. This clarifies the transmission process.
Visual 4: Comparison Chart - A chart comparing the key features of the Tsetse fly, Mosquito, Sand fly, and House fly to help differentiate between them.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Vector-borne transmission of African Trypanosomiasis (Sleeping Sickness) as background academic context rather than a clinical decision trigger.
A nurse taking a patient's history must inquire about recent travel, especially to sub-Saharan Africa, if symptoms like fever, severe headaches, irritability, and disturbed sleep patterns are present.
Early diagnosis is critical. The first stage (hemolymphatic) is easier to treat. The second stage (neurological), when the parasite crosses the blood-brain barrier, requires more complex, toxic treatments and can lead to coma and death if untreated.
Patient education is a key nursing role, involving advising travelers to endemic areas on preventive measures like wearing neutral-colored, thick clothing (tsetse flies are attracted to bright and dark colors), using insect repellent, and avoiding bushes during the day.

How to Approach the Question

First, identify the core of the question, which is to link a specific disease ('Sleeping sickness') with its biological vector.
Recall or deduce the common name for African Trypanosomiasis, which is 'sleeping sickness'.
Access your knowledge base on major vector-borne diseases. Associate the Tsetse fly with African Trypanosomiasis.
Systematically eliminate the other options by recalling the primary diseases they transmit: Mosquitoes (Malaria, Dengue), House flies (mechanical spread of enteric diseases), and Sand flies (Leishmaniasis).
Confirming that Tsetse fly is the correct vector for sleeping sickness solidifies the answer.

Concept Tested & Keywords

Concept Tested: Vector-borne transmission of African Trypanosomiasis (Sleeping Sickness)
Stem keywords: Sleeping sickness, caused by
Lead-in keywords: BEST, MOST RELEVANT CLUE
Negative lead-in flag: false

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