kosmos: List of superseded scientific theories

Evidence: 100 • authority: 72

This list includes well-known general theories in science and pre-scientific natural history and natural philosophy that have since been superseded by other scientific theories. Many discarded explanations were once supported by a scientific consensus, but replaced after more empirical information became available that identified flaws and prompted new theories which better explain the available data. Pre-modern explanations originated before the scientific method, with varying degrees of empirical support. Some scientific theories are discarded in their entirety, such as the replacement of the phlogiston theory by energy and thermodynamics. Some theories known to be incomplete or in some w…

Evidence: 36 • authority: 80

Pasteur, Silkworms, and the Germ Theory of Disease

Evidence: 36 • authority: 72

Anthrax is an infection caused by the bacterium Bacillus anthracis or Bacillus cereus biovar anthracis. Infection typically occurs by contact with the skin, inhalation, or intestinal absorption. Symptom onset occurs between one day and two months after the infection is contracted. The skin form presents with a small blister with surrounding swelling that often turns into a painless ulcer with a black center. The inhalation form presents with fever, chest pain, and shortness of breath. The intestinal form presents with diarrhea (which may contain blood), abdominal pains, nausea, and vomiting. According to the U.S. Centers for Disease Control and Prevention, the first clinical descriptions of…

Evidence: 36 • authority: 80

Louis Pasteur and the Germ Theory of Disease

Evidence: — • authority: 72

The fecal–oral route (also called the oral–fecal route or orofecal route) describes a particular route of transmission of a disease wherein pathogens in fecal particles pass from one person to the mouth of another person. Main causes of fecal–oral disease transmission include lack of adequate sanitation (leading to open defecation), and poor hygiene practices. If soil or water bodies are polluted with fecal material, humans can be infected with waterborne diseases or soil-transmitted diseases. Fecal contamination of food is another form of fecal-oral transmission. Washing hands properly after changing a baby's diaper or after performing anal hygiene can prevent foodborne illness from spread…

Evidence: — • authority: 72

A disease is a particular abnormal condition that adversely affects the structure or function of all or part of an organism and is not immediately due to any external injury. Diseases are often known to be medical conditions that are associated with specific signs and symptoms. A disease may be caused by external factors such as pathogens or by internal dysfunctions. For example, internal dysfunctions of the immune system can produce a variety of different diseases, including various forms of immunodeficiency, hypersensitivity, allergies, and autoimmune disorders. In humans, disease is often used more broadly to refer to any condition that causes or can cause pain, dysfunction, distress, so…

Evidence: — • authority: 72

The following outline is provided as an overview of and topical guide to concepts related to infectious diseases in humans. Infection – Subsequent to their transmission via environment and evasion or overcoming of defense, the entry/invasion, establishment, and replication of disease-causing microscopic organisms (pathogens or agents) inside a host organism, and the reaction of host tissues to them and to the toxins they produce. Infectious disease – illness or disorder when pathogenic (disease-causing) microorganisms, such as bacteria, viruses, fungi, or parasites invade and multiply within the body of a host organism and release toxins, causing various clinical symptoms which can potentia…

Evidence: — • authority: 72

In the mid to late nineteenth century, scientific patterns emerged which contradicted the widely held miasma theory of disease. These findings led medical science to what we now know as the germ theory of disease. Germ theory proposes that microscopic pathogens capable of replication (bacteria, viruses, etc.) are the cause of particular illnesses in both humans and animals. Prior to germ theory, people knew that diseases spread between humans, especially where many congregate, such as in armies and cities; but it was widely thought that this happened primarily due to exposure to unhealthy air (miasma) emanating from the sick or from people in general, as well as from swamps and conditions s…

Evidence: — • authority: 72

The miasma theory (also called the miasmic theory) is an abandoned medical theory that held that diseases—such as cholera, chlamydia, or plague—were caused by a miasma (μίασμα, Ancient Greek for pollution), a noxious form of "bad air", also known as night air. The theory held that epidemics were caused by miasma, emanating from rotting organic matter, the breath of humans and animals, and other odors. The theory explained why epidemics tend to happen in places with high population density, such as cities, as well as in swampy or hot and humid climates; and it addressed correlations between contagious diseases and lacking hygiene, lack of fresh air, and contacting the sick. Though miasma the…

Evidence: — • authority: 72

In medicine, public health, and biology, transmission is the passing of a pathogen causing communicable disease from an infected host individual or group to a particular individual or group, regardless of whether the other individual was previously infected. The term strictly refers to the transmission of microorganisms directly from one individual to another by one or more of the following means: airborne transmission – very small dry and wet particles that stay in the air for long periods of time allowing airborne contamination even after the departure of the host. Particle size < 5 μm. droplet transmission – small and usually wet particles that stay in the air for a short period of time.…

Evidence: — • authority: 72

The germ theory of disease is the currently accepted scientific theory explaining the cause of infectious diseases. It states that microorganisms known as pathogens or "germs" can cause disease. These small organisms, which are too small to be seen without magnification, invade animals, plants, and even bacteria. Their growth and reproduction within their hosts can cause disease. "Germ" refers not just to bacteria but to any type of microorganism, such as protists or fungi, or other pathogens, including parasites, viruses, prions, or viroids. Even when a pathogen is the principal cause of a disease, environmental and hereditary factors often influence the severity of the disease, and whethe…

Evidence: — • authority: 80

The germ theory, beriberi, and the deficiency theory of disease