Mansonia mosquito — DTM&H MCQ

Correct answer: E — Mansonia mosquito

The correct answer is E, Mansonia mosquito. Mansonia is the classic vector of Brugia malayi, the cause of brugian (Malayan) filariasis, and the stem's description of larvae attaching to aquatic plants to obtain oxygen is the pathognomonic ecological clue for this genus, since Mansonia larvae and pupae pierce plant roots (commonly water hyacinth or Pistia) with modified siphons rather than surfacing to breathe air. This unique respiratory adaptation ties the vector permanently to swampy or wetland habitats, exactly the setting described. Because vector and parasite life cycles are so tightly linked, this ecological detail is the discriminating feature examiners use to test recognition of brugian filariasis over other filarial or vector-borne diseases. Vegetation clearance is consequently a recognised vector control method specific to this genus. Why the other options are wrong: C. Simulium blackfly: this is the vector of Onchocerca volvulus (onchocerciasis), breeding in fast-flowing well-oxygenated rivers, not stagnant vegetated wetlands. B. Aedes mosquito: although Aedes can transmit Brugia in some settings, its larvae are free-swimming surface breathers in containers or pools, not plant-attached, so it does not match the described ecology. D. Anopheles mosquito: this is the principal vector for Wuchereria bancrofti and malaria, breeding in clean open water, and its larvae do not attach to submerged plant tissue for oxygen. A. Phlebotomine sandfly: this transmits leishmaniasis and sandfly fever, is terrestrial in breeding habits, and has no aquatic larval stage at all. Key point: larvae and pupae attaching to submerged aquatic plant roots for oxygen is the diagnostic ecological feature of Mansonia, the principal vector of Brugia malayi.

Reference: CDC DPDx, Lymphatic Filariasis: Biology, Mansonia and Aedes as typical vectors of Brugia spp., https://www.cdc.gov/dpdx/lymphaticfilariasis/index.html