Role of Chronic Bacterial and Viral Infections in Neurodegenerative, Neurobehavioral, Psychiatric, Autoimmune and Fatiguing Illnesses: Part 1
Garth L. Nicolson and Jörg Haier
Cite this article as: BJMP 2009:2(4) 20-28
Chronically ill patients with neurodegenerative, neurobehavioral and psychiatric diseases commonly have systemic and central nervous system bacterial and viral infections. In addition, other chronic illnesses where neurological manifestations are routinely found, such as fatiguing and autoimmune diseases, Lyme disease and Gulf War illnesses, also show systemic bacterial and viral infections that could be important in disease inception and progression or in increasing the number and severity of signs and symptoms. Evidence of Mycoplasma species, Chlamydia pneumoniae, Borrelia burgdorferi, human herpesvirus-1, -6 and -7 and other bacterial and viral infections revealed high infection rates in the above illnesses that were not found in controls. Although the specific roles of chronic infections in various diseases and their pathogeneses have not been carefully determined, the data suggest that chronic bacterial and/or viral infections are common features of progressive chronic diseases.
Chronic infections appear to be common features of various diseases, including neurodegenerative, psychiatric and neurobehavioral diseases, autoimmune diseases, fatiguing illnesses and other conditions.1-4 Neurodegenerative diseases, chronic degenerative diseases of the central nervous system (CNS) that cause dementia, are mainly diseases of the elderly. In contrast, neurobehavioral diseases are found mainly in younger patients and include autism spectrum disorders (ASD), such as autism, attention deficit disorder, Asperger’s syndrome and other disorders.5 For the most part, the causes of these neurological diseases remain largely unknown.2 Neurodegenerative diseases are characterized by molecular and genetic changes in nerve cells that result in nerve cell degeneration and ultimately nerve cell dysfunction and death, resulting in neurological signs and symptoms and dementia.2,3 On the other hand, neurobehavioral diseases are related to fetal brain development but are less well characterized at the cellular level and involve both genetic and environmental factors.6, 7 Even less well characterized at the cellular and genetic level are the psychiatric disorders, such as schizophrenia, paranoia, bipolar disorders, depression and obsessive-compulsive disorders.
Genetic linkages have been found in neurodegenerative and neurobehavioral diseases, but the genetic changes that occur and the changes in gene expression that have been found are complex and usually not directly related to simple genetic alterations.2, 6-8 In addition, it is thought that nutritional deficiencies, environmental toxins, heavy metals, chronic bacterial and viral infections, autoimmune immunological responses, vascular diseases, head trauma and accumulation of fluid in the brain, changes in neurotransmitter concentrations, among others, are involved in the pathogenesis of various neurodegenerative and neurobehavioral diseases.2, 3, 5-16 One of the biochemical changes found in essentially all neurological, neurodegenerative and neurobehavioral diseases is the over-expression of oxidative free radical compounds (oxidative stress) that cause lipid, protein and genetic structural changes.9-11 Such oxidative stress can be caused by a variety of environmental toxic insults, and when combined with genetic factors could result in pathogenic changes.14
In the British Jounal of Medical Practitioners well worth accessing the link above and reading the full article.