PD Guide

Biologic Agents

Environmental Factors, Occupation, Olfactory Testing, Neuroimmune Function

The 1918 Influenza virusImage by Cynthia Goldsmith and Terrence Tumpey, CDCThe 1918 Influenza virusImage by Cynthia Goldsmith and Terrence Tumpey, CDCBoth bacterial and viral pathogens have been hypothesized to act as triggers to PD or related parkinsonism (Kasten et al., 2007). One of the most famous examples includes the increased occurrence of postencephalitic parkinsonism seen after the influenza pandemic in the 1920s (Jang et al., 2008).

Indirect support for a possible role of a biological pathogenic agent has been suggested by neuropathological studies in human post mortem brain. An apparent progressive pattern of PD-related neuropathology beginning in the enteric nervous system (Braak et al., 2003) has been interpreted by some as suggestive of origin in a gut infection. The association of some occupations, such as teaching and healthcare work (Goldman et al., 2005), to increased risk of PD may also point to possible infectious causes.

Although viral and bacterial infections can apparently induce some forms of parkinsonism, whether these represent true causes of idiopathic PD remains unclear and controversial.

Reference: 
Kasten M, Chade A, Tanner CM. Epidemiology of Parkinson's disease. Handbook of clinical neurology / edited by P.J. Vinken and G.W. Bruyn. 2007;83:129-51.
Jang H, Boltz DA, Webster RG, Smeyne R. Viral parkinsonism. Biochim Biophys Acta. 2008.
Braak H, Del Tredici K. Invited Article: Nervous system pathology in sporadic Parkinson disease. Neurology. 2008;70(20):1916-25.
Goldman SM, Tanner CM, Olanow CW, Watts RL, Field RD, Langston JW. Occupation and parkinsonism in three movement disorders clinics. Neurology. 2005;65(9):1430-5.
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