This study examines the feasibility of using a smartphone application (app) to conduct surveys among travellers during the Hajj pilgrimage. where the use of apps has not been evaluated for infectious disease surveillance. A longitudinal study was conducted among pilgrims at the Hajj 2014 using an iPhone app with separate questionnaires for three study phases covering before. during. https://www.roneverhart.com/Milwaukee-2485-22-M12-FUEL-Right-Angle-Die-Grinder-Kit/