The germ theory of disease

The history of germ theory Jemima Hodkinson explores germ theory and two of the scientists behind it: People have created theories to explain human disease for millennia: In the 19th century, improvements in microscope technology enabled a generation of microbiologists to investigate further the world of previously unseen disease-causing organisms. Many of these scientists carried out research that contributed towards the formation of the germ theory.

The germ theory of disease

Prev Chronic Dis ;9: This focus on a predominant cause of infections ie, microbial pathogens ultimately led to medical and public health advances eg, immunization, pasteurization, antibiotics.

Germ theory of disease - Wikipedia

However, the resulting declines in infections in the 20th century were matched by a rise in chronic, noncommunicable diseases, for which there is no single underlying etiology. Top of Page Introduction Throughout history, infections have posed the biggest challenge to human health.

This challenge changed in the 19th and 20th centuries because of economic development and improvements initiated largely by the Industrial Revolution — public health and hygiene, the advent of antibiotics and vaccinations, and, driving these, the consolidation of the germ theory of disease 1.

Midth—century optimism, however, was dampened by the reality of an epidemiological transition 2 that occurs with economic development. Chronic diseases and conditions are defined here as those that are noncommunicable, lasting, recurrent, and without a primary microbial cause. The same transition is occurring now in rapidly developing countries, such as China and Mexico, and is predicted in late-developing countries, such India and Bangladesh 1.

Harris 1Anderson 5and others have charted the differences in thinking these changes have brought to modern epidemiology, emphasizing the difficulties in assigning causality when shifting from a mono-causal focus promoted by the germ theory to address infectious disease to a multi-causal focus to address chronic disease.

No equivalent of the germ theory has provided a unifying understanding of chronic disease etiology. The aging of the population and the dysmetabolism associated with aging has affected the prevalence of chronic disease; however, the increase in the prevalence of chronic diseases and associated risk factors and behaviors among all age groups limits aging as a sole explanation.

Genetic influences and gene—age interactions are also incomplete explanations, in light of the sudden increase in and other known causes of chronic diseases.

Many behaviors and environmental factors have been implicated, but a unifying theoretical underpinning has not been identified. The discovery of a form of otherwise unrecognized inflammation in the early s 6 and its widespread presence in many chronic diseases 7 led to the suggestion that many, if not all, such diseases may have this type of inflammatory basis 8.

Top of Page Inflammation and Disease For more than 2, years, classical inflammation has been recognized by the symptoms identified by the Roman physician Aurelius Celsus as pain dolorredness ruborheat calorand swelling tumorwith the more recent addition of loss of function torpor.

This form of classical inflammation is typically a short-term response to infection and injury, aimed at removing the infective stimulus and allowing repair of the damaged tissue, ultimately resulting in healing and a return to homeostasis.

However, inresearchers discovered a different type of prolonged, dysregulated, and maladaptive inflammatory response associated with obesity, which they suggested may explain the disease-causing effects of excessive weight gain 6.

In essence, although classical inflammation has a healing role in acute disease, metaflammation, because of its persistence, may have a mediating role, helping to aggravate and perpetuate chronic disease. The difference between these 2 forms of inflammation is illustrated in Figure 1. The scale of difference of immune reaction between the 2 forms ie, approximately fold is not shown.

Possible reasons for these associations include facilitation of atherosclerosis 11development of insulin resistance 12endoplasmic reticular stress 13and changes in gut microbiota Metaflammation may be part of a causal cascade, including endoplasmic reticular stress and insulin resistance, or simply a defensive reaction to persistent stimuli that induce chronic disease.

However, mounting evidence suggests metaflammation may develop as an intermediate immune system response to certain inducers, which, if maintained, can lead to the development and maintenance of dysmetabolic conditions and chronic disease 7,9. A commonly expressed view is that obesity is a prerequisite for metaflammation to occur or that metaflammatory inducers are necessarily either nutritional overload or nutrient-based.

The germ theory of disease

Top of Page Metaflammation and Anthropogens An increasing number of pro- or anti-inflammatory biomarkers for measuring metaflammation have recently been identified 16and several avenues of research have sought to identify their nutritional, behavioral, and environmental inducers 10, Many inducers have been identified Table.Germ theory states that specific microscopic organisms are the cause of specific diseases.

Germ theory is also called the pathogenic theory of medicine.

The germ theory of disease

Germ theory led in to the development of antibiotics and hygienic practices. Before germ theory became widely accepted, people had other theories to explain the causes of disease.

Research two of these and write a paragraph about each. The links above and below might be useful (‘From miasmas to germs’ in particular). Proving the germ theory of disease was the crowning achievement of the French scientist Louis Pasteur. He was notthe first to propose that diseases were caused by microscopic organisms, but the view was controversial in the 19th century, and opposed the accepted theory of “spontaneous generation”.

Sep 09,  · In , Norins launched Alzheimer's Germ Quest Inc., a public benefit corporation he hopes will drive interest into the germ theory of Alzheimer's, and through which his .

Germ theory, in medicine, the theory that certain diseases are caused by the invasion of the body by microorganisms, organisms too small to be seen except through a microscope.

Sidebar: Overcoming Disease

The French chemist and microbiologist Louis Pasteur, the English surgeon Joseph Lister, and the German physician Robert.

The germ theory of disease is the currently accepted scientific theory of disease. It states that many diseases are caused by microorganisms. These small organisms, too small to see without magnification, invade humans, animals, and other living hosts.

Germ theory of disease - Wikipedia