AbstractThe etiology of Parkinson's disease remains unknown, and a search for environmental agents continues. In 1985, Fishman (10) induced infection of the basal ganglia by a coronavirus in mice. Although coronavirus is recognized primarily as a respiratory pathogen in humans, its affinity for the basal ganglia led us to investigate its possible role in human Parkinson's disease. The cerebrospinal fluid of normal controls (CTL) (n = 18), and patients with Parkinson's disease (PD(n = 20)) and other neurological disease (OND) (n = 29) was analyzed in a blinded manner by enzyme‐linked immunosorbent assay [measurements in optical density (OD) units] for antibody response to four coronavirus antigens: mouse hepatitis virus JHM (J) and A59 (A), and human coronavirus 229E (E) and OC43 (O). When compared with CTL, PD patients had an elevated (p0.05) to O (0.0839 vs. 0.0071) was greater than that to E (0.1261 vs. 0.0743). When compared to OND, PD patients had an elevated mean OD response to J (0.0856 vs. 0.0267, p0.05) to A (0.1722 vs. 0.0929) and O (0.0839 vs. 0.0446) were greater than that to E (0.1261 vs. 0.0946). These results suggest that there may be an association between coronavirus and P