How is Leishmania transmitted to humans?

Leishmania is transmitted to humans primarily through the bites of infected sandflies, which are the principal vectors for this parasitic infection. When a sandfly bites a human, it injects the parasite into the bloodstream, where it can then lead to various forms of leishmaniasis, depending on the species of Leishmania involved and the immune response of the human host.

This method of transmission is distinct and highly specific; the other options do not play a role in the transmission of Leishmania. For instance, contaminated water and direct contact with infected soil do not facilitate the spread of the parasite, and consumption of undercooked meat is irrelevant to Leishmania transmission, as it is not a foodborne parasite. Understanding this specific mode of transmission is crucial for preventing leishmaniasis, particularly in areas where sandflies are prevalent.