In this work we will develop and field validate FeverPhone technology for point-of-care differential diagnosis of six common causes of acute febrile illness (namely: Dengue, Malaria, Chikungunya, Leptospirosis, Typhoid fever, and Chagas). The FeverPhone system builds on our team's extensive background on the development of smartphone based diagnostics, infectious disease, and global health. The technical effort of this program comprises of the development of: a specialized 6-plexed colorimetric IgM/IgG assay cartridge that exploits our previous work on color discrimination assays on mobile devices, associated iPad based hardware that allows rapid interpretation of the cartridge results on a platform already used by our field technicians, and software that will combine differential molecular diagnosis with a confirmatory symptomatic interface used by the operator. The final system will enable actionable diagnosis in around 15 minutes. In parallel with technical development, we will perform a staged field validation study at our existing infectious diseases monitoring site in Machala, Ecuador. In addition to clinical and engineering expertise, we have incorporated a translation partner into the program that will ensure that our system is fully validated and ready for FDA approval by the end of the effort.