Could happen to a better group. Go parasite!!!
Alas the species of Leishmaniasis common in Iraq/Syria area mainly cause skin ulcers and aren’t very likely to kill them, just scar them up badly. If your strategy to get sex is raping captives and slaves it doesn’t matter that you look disgusting. This may not slow down those already fighting for ISIS much. If ‘our’ leaders were PR, instead of PC, savvy they might be able to impact ISIS’s recruiting pushing this story.