Rheumatoid arthritis (RA) is a relatively common and potentially disabling immune-mediated inflammatory systemic disease, predominantly affecting women and characterised by multiple small joint arthritis. Extensive data supports the roles of genetic, environmental and microbial factors in the triggering and development of this disease. Proteus mirabilis is considered as the main microbial culprit in the causation of RA. The evidence for the role of these microbes in RA and their links with commonly associated autoantibodies such as rheumatoid factors and anti-citrullinated peptide antibodies have been elucidated together with their relations with some of the non-microbial environmental factors which have been implicated in the aetiopathogenesis of RA. The most likely mechanism in the development of RA is "molecular mimicry" where Proteus antigens were found to share homologous sequences, which cross-react with certain self-antigens present in synovial tissues. This could raise possibilities for implementing a new therapeutic strategy in the treatment of RA.

Ankylosing spondylitis (AS) is a world-wide chronic inflammatory disease of the axial skeleton most likely caused by a microbial factor in genetically susceptible individuals. Over the last 40 years extensive data has been produced which shows that the majority of patients with AS possess the HLA-B27 genetic marker. Significantly elevated levels of Klebsiella antibodies have been demonstrated in 1556 AS patients in 16 different countries with various geographical locations. Other evidence for the link between Klebsiella and AS include increased fecal isolation rates of Klebsiella microbes in AS patients together with shared molecular and immunological cross-reactivity features existing between Klebsiella antigens and HLA-B27 and collagens I, III and IV. Anti-Klebsiella measures could possibly be included with the currently used medical treatment in the management of patients with AS.

Patients with multiple sclerosis (MS) and some with Creutzfeldt–Jakob disease (CJD) have elevated levels of antibodies to the nasal microbe Acinetobacter. Both patients with MS and patients with CJD exhibit features of inflammation. Acinetobacter bacteria possess sequences resembling myelin and neurofilaments. It is suggested that immunoglobulin G anti-Acinetobacter antibodies produced in an extrathecal space, acting as autoantibodies, are the causative agents of these diseases.

Abstract Bovine spongiform encephalopathy, scrapie, as well as Creutzfeldt–Jakob disease and kuru belong to a group of related neurological conditions termed transmissible spongiform encephalopathies. These diseases are based on the LD 50 measurement whereby saline brain homogenates are injected into experimental animals and when 50% of them develop symptoms, this is considered as transmission of the disease, but the gold standard for diagnosis is autopsy examination. However, an untenable assumption is being made in that saline brain homogenates do not cause tissue damage but it is known since the time of Pasteur, that they give rise to post-rabies vaccination allergic encephalomyelitis. This is the fundamental flaw in the diagnosis of these diseases. A way forward, however, is to examine infectious agents, such as Acinetobacter which show molecular mimicry with myelin and elevated levels of antibodies to this microbe are found in multiple sclerosis patients and animals affected by bovine spongiform encephalopathy.

Ankylosing spondylitis (AS) is a chronic inflammatory arthritis mainly affecting the spinal joints. It would appear that the most likely causative agent in the development of AS is an environmental factor in the genetically susceptible, HLA-B27 positive, individuals. Extensive data from several countries support the notion that Klebsiella pneumonia bacteria are the most likely culprit in the causation of AS. These microbes possess antigens which resemble HLA-B27 and spinal collagens. Increased intake of high-starch diet is directly proportional to the gut-associated bacterial load, especially in the large intestine, and among these microbial agents, Klebsiella is considered as one of the main constituting components. Therefore, a low-starch diet intake alongside the currently used medical therapeutic modalities could be beneficial in the management of patients with early AS. It is suggested that a change in the dietary habits from high protein, low-starch marine components to the Westernized high-starch diet among the Inuit peoples of Alaska and Canada could be considered as one of the main contributing factors in the increased prevalence of AS during the last few decades within this genetically unmixed native population.

“Bovine spongiform encephalopathy”, “scrapie”, as well as Creutzfeldt–Jakob disease and kuru belong to a group of related neurological conditions termed “transmissible spongiform encephalopathies”. These diseases are based on the LD50 measurement whereby saline brain homogenates are injected into experimental animals and when 50% of them develop symptoms, this is considered as transmission of the disease, but the gold standard for diagnosis is autopsy examination. However, an untenable assumption is being made in that saline brain homogenates do not cause tissue damage but it is known since the time of Pasteur, that they give rise to “post-rabies vaccination allergic encephalomyelitis”. This is the fundamental flaw in the diagnosis of these diseases. A way forward, however, is to examine infectious agents, such as Acinetobacter which show molecular mimicry with myelin and elevated levels of antibodies to this microbe are found in multiple sclerosis patients and animals affected by “bovine spongiform encephalopathy”.