Leishmaniasis is endemic in some area of Israel (it is also known as "Jericho Fever"). From what I read about the sand fly, it can only fly close to the ground. So If you sleep on a bed that is over 70cm high you should be safe (unless one of your limbs extends down while you sleep). Also, once the body overcomes the infection, you become immune to it. But people can be bitten multiple times and suffer terrible scarring before they overcome the parasite. The Bedouins set their babies to sleep at night wrapped with blankets but with their buttocks exposed to purposely get them bitten in the buttock and develop immunity so to avoid scars in more prominent areas like the face.