Which of the following diseases is transmitted by the bite of an infected fly?

Leishmaniasis is transmitted by the bite of infected female phlebotomine sand flies. These flies serve as vectors for the Leishmania parasites, which can infect humans and cause a variety of forms of leishmaniasis, including cutaneous, mucocutaneous, and visceral leishmaniasis. The transmission occurs when an infected sand fly bites a human, injecting the parasites into the skin or bloodstream.

In contrast, malaria is transmitted through infected Anopheles mosquitoes, not flies. Dengue fever is spread by Aedes mosquitoes, particularly Aedes aegypti and Aedes albopictus. Chagas disease is transmitted primarily by triatomine bugs, often referred to as "kissing bugs," rather than flies. Each of these diseases has specific vectors that carry the pathogens, making the identification of the responsible insect crucial in understanding the transmission routes. This reinforces the importance of targeting appropriate vectors in prevention and control measures for these diseases.