[1] Tel Aviv Univ, Dept Epidemiol & Prevent Med, Sch Publ Hlth, Sackler Fac Med, IL-69978 Tel Aviv, Israel
[2] Tel Aviv Univ, Ctr Study Bioterrorism, IL-69978 Tel Aviv, Israel
[3] Ben Gurion Univ Negev, Dept Epidemiol, Fac Hlth Sci, IL-84105 Beer Sheva, Israel