Figure Legends
Figure 1. Life cycles of zoonotic vs anthroponotic
spread of Leishmania spp . Animals depicted have been documented
as a blood source in Leishmania positive sand flies.
Figure 2. Distribution of L. donovani complex
spp. and different transmission ecologies. AVL= anthroponotic VL, ZVL=
zoonotic VL.
Figure 3. The skin as a predominant source forLeishmania parasites in different clinical settings. Sand flies
use their serrated proboscis to probe the skin for dermal blood vessels
creating a pool of blood from which to feed. Asymptomatic L.
donovani infection provides a setting with productive immunity and a
relatively low parasite load in the skin and blood. During symptomatic
VL, high parasitemia and patches of highly parasitized macrophages in
the skin lead to a highly increased chance of sand fly infection during
feeding. PKDL is associated with an immune response againstLeishmania parasites in the skin and therefore is characterized
by a significant parasite burden within dermal macrophages. After
treatment for VL, parasitemia may diminish before parasites in the skin
are eradicated. However, patients with both forms of PKDL have been
found to be readily infectious to sand fly vectors. Nodular/papular PKDL
patients, shown to have significantly increased parasite burden in the
skin compared to macular PKDL, are more infectious to sand flies than
macular PKDL patients.