Understanding the factors that determine the emergence of anthroponotic
cutaneous leishmaniasis due to Leishmania tropica: Comparison of the
density and mitochondrial lineage of Phlebotomus sergenti between
endemic and free areas in Morocco
Anthroponotic cutaneous leishmaniasis (ACL) due to Leishmania tropica is
spreading to new areas. Exposure to the vector, Phlebotomus sergenti, is
the only proven risk factor. Our objective was to compare the densities
and genetic characteristics of P. sergenti populations in two nearby
localities in Morocco, one within an ACL endemic area (El Borouj) and
another undamaged (Sidi Hajjaj). Statistically significant differences
were detected between P. sergenti densities with a higher density of P.
sergenti in the endemic town (p≤ 0.032). A different main P. sergenti
mitochondrial lineage was evidenced in each one of the 2 localities, and
for the first time, the lineage of P. sergenti specimens that are acting
as a vector of L. tropica has been identified. Bioclimatic differences
were detected between both localities. In conclusion, between an ACL
endemic locality and another ACL free there are differences in both the
density of P. sergenti and the mitochondrial lineage that may explain
the different epidemiological situation. Given that the density of P.
sergenti in the locality without ACL cases seems sufficient to allow
transmission, the main factor that would justify its ACL undamaged
character could be the absence of P. sergenti Lineage IV, which seems to
prefer warmer and drier climates.