A review of

Understanding why Diptera, such as mosquitoes and sand flies, feed on humans is crucial in defining them as vectors of diseases such as malaria, dengue fever, Zika virus, and leishmaniasis. Determining their attraction to humans (anthropophily) helps in assessing the risk of disease transmission, designing effective vector control strategies, and monitoring the effectiveness of existing control measures. An important question is whether they are specifically attracted to humans in preference to other mammals or whether there is something else at play. In this paper, I propose that the idea that saying species are “anthropophilic” when they are preferentially attracted to humans is misleading and that such species are generalists that will opportunistically feed on a wide range of animals including humans when they are available. Other species are specialists that, under rare circumstances, accidently feed on humans. For these groups, I propose the names anthropportunists and anthroaccidentalists, respectively. The level of contact depends on a range of environmental factors and it is these that must be considered in evaluating potential vector importance and management. In this paper, I propose a review of the Leishmania identified in American sand flies and relate them to these two concepts and how it is linked to taxonomic groups, evolution, and ecology. There are records of Leishmania in 91 species, which is only 16.5% of American sand fly species. Of these infections, 56.7% are in the genera Lutzomyia, Nyssomyia, Pintomyia, and Psychodopygus, which are typically generalist anthropportunists. Of the species considered to be proven vectors, 77.4% belong to these four genera. As infections were detected by a variety of methods, further case-by-case field studies are required to evaluate the vectorial role of many of the sand fly species in which Leishmania have been found.