Viral parkinsonism

Abstract

Parkinson's disease is a debilitating neurological disorder characterized that affects 1-2% of the adult population over 55 years of age. For the vast majority of cases, the etiology of this disorder is unknown, although it is generally accepted that there is a genetic susceptibility to any number of environmental agents. One such agent may be viruses. It has been shown that numerous viruses can enter the nervous system, i.e. they are neurotropic, and induce a number of encephalopathies. One of the secondary consequences of these encephalopathies can be parkinsonism, that is both transient as well as permanent. One of the most highlighted and controversial cases of viral parkinsonism is that which followed the 1918 influenza outbreak and the subsequent induction of von Economo's encephalopathy. In this review, we discuss the neurological sequelae of infection by influenza virus as well as that of other viruses known to induce parkinsonism including Coxsackie, Japanese encephalitis B, St. Louis, West Nile and HIV viruses.

Contributions of central and systemic inflammation to the pathophysiology of Parkinson's disease

“…PEP shares cardinal symptomatology with idiopathic PD including rigidity and bradykinesia but a lack of Lewy body formation (Jang et al, 2009a). Moreover, Takahashi et al, 1995 demonstrated that the H1N1 virus preferentially targets the SNpc, the primary site of pathology in PD (Takahashi et al, 1995).…”

“…This emerging "two-hit hypothesis" in the aetiology of neurodegenerative diseases such as PD, suggests that the disease is multifactorial, and possibly a consequence of "multiple-hits" involving a variety of inflammatory stimuli (Di Monte, 2003). Infectious agents may comprise the first "hit", therefore sensitising the brain to subsequent "hits", which may not have been pathogenic in the absence of an already "primed" system (Jang et al, 2009a). In this instance, microglia in the aged or diseased brain are said to be "primed"…”

“…Associations were first established towards the end of the first world war when the H1N1 influenza-A pandemic was coupled with a dramatic increase in post-encephalitic Parkinsonism (PEP) (also referred to as "sleeping sickness" or von Economo encephalitis) (Jang et al, 2009a;Rail et al, 1981;Tansey et al, 2007). People born during this time were at a 2-3 fold increased risk of developing PD, with PEP implicated in 50% of all Parkinsonism cases (Jang et al, 2009a;Tansey et al, 2007).…”

Inflammation in Parkinson’s Disease: Causes and Consequences

“…Moreover, oxidative stress preferentially affects DA neurons in the SNpc, which are particularly vulnerable as they operate under high oxidant conditions due to reduced levels of the anti-oxidant glutathione (Misra & Kalita, 2010;Sian et al, 1994). Accordingly, it has been postulated that pre-exposure to environmental toxins such as heavy metals, organophosphate compounds, neurotoxins, and pesticides like paraquat and rotenone which can induce oxidative stress and the generation of free radicals, increases the susceptibility to the development of PD in later life (Calne & Langston, 1983;Jang et al, 2009a). Pathological and clinical evidence has also identified the involvement of the gastrointestinal tract in enhancing susceptibility to idiopathic Parkinsonism, with Helicobacter pylori infection proposed as a potential trigger in disease progression (Tansey & Goldberg, 2010;Weller et al, 2005).…”

“…Postulated risk factors implicated in idiopathic PD include age, genetic predisposition, bacterial or viral infections, neuronal injury such as traumatic brain injury or stroke, and environmental toxins (Koprich et al, 2008;Tansey & Goldberg, 2010). Associations were first established towards the end of the first world war when the H1N1 influenza-A pandemic was coupled with a dramatic increase in post-encephalitic Parkinsonism (PEP) (also referred to as "sleeping sickness" or von Economo encephalitis) (Jang et al, 2009a;Rail et al, 1981;Tansey et al, 2007). People born during this time were at a 2-3 fold increased risk of developing PD, with PEP implicated in 50% of all Parkinsonism cases (Jang et al, 2009a;Tansey et al, 2007).…”