As of November 21, 360 cases of eosinophilia-myalgia syndrome (EMS) had been reported by state health departments to CDC. Studies examining an association of L-tryptophan-containing products (LTCPs) with the EMS epidemic1 have been completed in New Mexico, Minnesota, and Oregon. In addition, a fatal case in New York has been reported.
In a New Mexico casecontrol study, EMS cases (N = 12) were all persons for whom an eosinophil count of 2000 cells/mm3 was recorded from May 1 through November 11, 1989, in nine laboratories in Albuquerque, Santa Fe, and Los Alamos and for whom incapacitating myalgia was documented, either in the medical record or by interview with the patient. Potential cases were excluded if eosinophilia could have been caused by any of a predetermined list of approximately 20 infectious, neoplastic, allergic, or other chronic diseases. EMS cases were compared with controls (two per case) who had been