Amyotrophic lateral sclerosis (ALS) has recently received public attention from reports of apparent clusters of cases. The best known (and studied) of these clusters or foci of ALS is on Guam. The lay press has recently emphasized the cluster of three professional "49-er" footballers associated with use on the practice field of a fertilizer, Milorganite, known to contain toxic elements such as cadmium and mercury (C. Petit. San Francisco Chronicle, April 13, 1989). To aid in assessing the possibility of that exposure in the etiology of ALS, we surveyed the patients currently in our San Francisco, Calif, ALS Clinic.
We also included a questionnaire about pets, because Schenkman et al1 found that patients with ALS had been exposed to more household pets than the control subjects, although Mulder et al2 did not confirm that finding. Neither survey was population based.
Our patients were asked about exposure to Milorganite and
Norris FH, Padia LA. Toxic and Pet Exposures in Amyotrophic Lateral Sclerosis. Arch Neurol. 1989;46(9):945. doi:10.1001/archneur.1989.00520450015004