Which of the following is NOT mosquito borne disease ?
- (a)Dengue fever
- (b)Filariasis
- (c)Sleeping sickness
- (d)Malaria
Correct — C, Sleeping sickness. Sleeping sickness (African trypanosomiasis) is caused by Trypanosoma protozoa and is transmitted by the bite of the tsetse fly (Glossina) — NOT a mosquito. The other three options are all mosquito-borne, so sleeping sickness is the odd one out.
- (a)Dengue fever — Dengue is a viral disease spread by the Aedes (Aedes aegypti) mosquito — hence it IS mosquito-borne, so it cannot be the answer to a 'NOT' question.
- (b)Filariasis — Lymphatic filariasis (elephantiasis) is caused by filarial worms transmitted by the Culex mosquito — mosquito-borne.
- (d)Malaria — Malaria is caused by Plasmodium and transmitted by the female Anopheles mosquito — the classic mosquito-borne disease.
Vector-borne diseases are classified by their carrier. Mosquito vectors include Anopheles (malaria), Aedes (dengue, chikungunya, yellow fever, Zika) and Culex (lymphatic filariasis, Japanese encephalitis). The tsetse fly (Glossina) transmits African sleeping sickness — a fly, not a mosquito.
Three options share a mosquito vector, so the trick is to know that sleeping sickness rides the tsetse fly. Reason from the vector of each disease rather than from its pathogen.
- Sleeping sickness (African trypanosomiasis) → tsetse fly (Glossina) vector; caused by Trypanosoma
- Malaria → female Anopheles mosquito (Plasmodium)
- Dengue → Aedes aegypti mosquito (a virus)
- Lymphatic filariasis → Culex mosquito (filarial worms)
- Assuming any tropical fever must be mosquito-borne
- Confusing the vector (tsetse fly) with the pathogen (Trypanosoma)
As an 'odd one out / NOT' item or a disease↔vector match.
Consider the following statements: 1. Dengue is a protozoan disease transmitted by mosquitoes. 2. Retro-orbital pain is not a symptom of Dengue. 3. Skin rash and bleeding from nose and gums are some of the symptoms of Dengue. Which one of the following statements is/are correct?
- (a) 1 and 2
- (b) 3 only
- (c) 2 only
- (d) 1 and 3
Answer(b) 3 only
Same concept — mosquito-borne disease facts; statement 1 ('Dengue is a protozoan disease') is wrong (dengue is viral, spread by the Aedes mosquito), so only statement 3 is correct.
- practice — not a real PYQ
Kala-azar (visceral leishmaniasis) is transmitted by the bite of which vector?
- (a)Tsetse fly
- (b)Sandfly
- (c)Aedes mosquito
- (d)Tick
Answer(b) Sandfly (Phlebotomus) — it transmits the Leishmania parasite.
- practice — not a real PYQ
Which mosquito is the vector of lymphatic filariasis?
- (a)Anopheles
- (b)Aedes
- (c)Culex
- (d)Mansonia
Answer(c) Culex — it transmits the filarial worms causing elephantiasis.