Cholera is an infection of the small intestine by some strains of the bacterium Vibrio cholerae. Symptoms may range from none, to mild, to severe. The classic symptom is large amounts of watery diarrhea lasting a few days. Vomiting and muscle cramps may also occur. Diarrhea can be so severe that it leads within hours to severe dehydration and electrolyte imbalance. This may result in sunken eyes, cold skin, decreased skin elasticity, and wrinkling of the hands and feet. Dehydration can cause the skin to turn bluish. Symptoms start two hours to five days after exposure.
Vibrio cholerae is a species of Gram-negative, facultative anaerobe and comma-shaped bacteria. The bacteria naturally live in brackish or saltwater where they attach themselves easily to the chitin-containing shells of crabs, shrimp, and other shellfish. Some strains of V. cholerae are pathogenic to humans and cause a deadly disease called cholera, which can be derived from the consumption of undercooked or raw marine life species or drinking contaminated water.
The germ theory of disease is the currently accepted scientific theory for many 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 humans, other animals, and other living hosts. Their growth and reproduction within their hosts can cause disease. "Germ" refers to not just a bacterium but to any type of microorganism, such as protists or fungi, or other pathogens that can cause disease, such as viruses, prions, or viroids. Diseases caused by pathogens are called infectious diseases. Even when a pathogen is the principal cause of a disease, environmental and hereditary factors often influence the severity of the disease, and whether a potential host individual becomes infected when exposed to the pathogen. Pathogens are disease-carrying agents that can pass from one individual to another, both in humans and animals. Infectious diseases are caused by biological agents such as pathogenic microorganisms as well as parasites.
Drinking water or potable water is water that is safe for ingestion, either when drunk directly in liquid form or consumed indirectly through food preparation. It is often supplied through taps, in which case it is also called tap water.
Water purification is the process of removing undesirable chemicals, biological contaminants, suspended solids, and gases from water. The goal is to produce water that is fit for specific purposes. Most water is purified and disinfected for human consumption, but water purification may also be carried out for a variety of other purposes, including medical, pharmacological, chemical, and industrial applications. The history of water purification includes a wide variety of methods. The methods used include physical processes such as filtration, sedimentation, and distillation; biological processes such as slow sand filters or biologically active carbon; chemical processes such as flocculation and chlorination; and the use of electromagnetic radiation such as ultraviolet light.
The miasma theory is an abandoned medical theory that held that diseases—such as cholera, chlamydia, or the Black Death—were caused by a miasma, 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. Though miasma theory is typically associated with the spread of contagious diseases, some academics in the early nineteenth century suggested that the theory extended to other conditions as well, e.g. one could become obese by inhaling the odor of food.
Cryptosporidiosis, sometimes informally called crypto, is a parasitic disease caused by Cryptosporidium, a genus of protozoan parasites in the phylum Apicomplexa. It affects the distal small intestine and can affect the respiratory tract in both immunocompetent and immunocompromised individuals, resulting in watery diarrhea with or without an unexplained cough. In immunosuppressed individuals, the symptoms are particularly severe and can be fatal. It is primarily spread through the fecal-oral route, often through contaminated water; recent evidence suggests that it can also be transmitted via fomites contaminated with respiratory secretions. Cryptosporidium is commonly isolated in HIV-positive patients presenting with diarrhea.
Raw milk or unpasteurized milk is milk that has not undergone pasteurization, a process of heating liquid foods to kill pathogens for safe consumption and extension of shelf life.
Campylobacteriosis is among the most common infections caused by a bacterium in humans, often as a foodborne illness. It is caused by the Campylobacter bacterium, most commonly C. jejuni. It produces an inflammatory, sometimes bloody, diarrhea or dysentery syndrome, and usually cramps, fever and pain.
Travelers' diarrhea (TD) is a stomach and intestinal infection. TD is defined as the passage of unformed stool while traveling. It may be accompanied by abdominal cramps, nausea, fever, headache and bloating. Occasionally dysentery may occur. Most travelers recover within three to four days with little or no treatment. About 12% of people may have symptoms for a week.
John Snow was an English physician and a leader in the development of anaesthesia and medical hygiene. He is considered one of the founders of modern epidemiology and early germ theory, in part because of his work in tracing the source of a cholera outbreak in London's Soho, which he identified as a particular public water pump. Snow's findings inspired fundamental changes in the water and waste systems of London, which led to similar changes in other cities, and a significant improvement in general public health around the world.
Cryptosporidium, sometimes called crypto, is an apicomplexan genus of alveolates which are parasites that can cause a respiratory and gastrointestinal illness (cryptosporidiosis) that primarily involves watery diarrhea, sometimes with a persistent cough.
Health geography is the application of geographical information, perspectives, and methods to the study of health, disease, and health care. Medical geography, a sub-discipline of, or sister field of health geography, focuses on understanding spatial patterns of health and disease in relation to the natural and social environment. Conventionally, there are two primary areas of research within medical geography: the first deals with the spatial distribution and determinants of morbidity and mortality, while the second deals with health planning, help-seeking behavior, and the provision of health services.
Portable water purification devices are self-contained, easily transported units used to purify water from untreated sources for drinking purposes. Their main function is to eliminate pathogens, and often also suspended solids and some unpalatable or toxic compounds.
The 2006 North American E. coli outbreak was an Escherichia coli O157:H7 outbreak from prepackaged spinach reported in 27 U.S. states and the Canadian province of Ontario. The outbreak cases spanned from August 30 to October 6, and its origin was traced back to a farm in San Benito County, California. At least 276 consumer illnesses and 3 deaths have been attributed as a result from the outbreak.
The discovery of disease-causing pathogens is an important activity in the field of medical science. Many viruses, bacteria, protozoa, fungi, helminths, and prions are identified as a confirmed or potential pathogen. In the United States, a Centers for Disease Control and Prevention program, begun in 1995, identified over a hundred patients with life-threatening illnesses that were considered to be of an infectious cause but that could not be linked to a known pathogen. The association of pathogens with disease can be a complex and controversial process, in some cases requiring decades or even centuries to achieve.
Water supply and sanitation in Canada is nearly universal and generally of good quality, but a lack of clean drinking water in many First Nations communities remains a problem. Water use in Canada is high compared to Europe, since water tariffs are low and 44% of users are not metered.
The Broad Street cholera outbreak was a severe outbreak of cholera that occurred in 1854 near Broad Street in Soho, London, England, and occurred during the 1846–1860 cholera pandemic happening worldwide. This outbreak, which killed 616 people, is best known for the physician John Snow's study of its causes and his hypothesis that germ-contaminated water was the source of cholera, rather than particles in the air. This discovery came to influence public health and the construction of improved sanitation facilities beginning in the mid-19th century. Later, the term "focus of infection" started to be used to describe sites, such as the Broad Street pump, in which conditions are favourable for transmission of an infection. Snow's endeavour to find the cause of the transmission of cholera caused him to unknowingly create a double-blind experiment.
The history of water filters can be traced to the earliest civilisations with written records. Water filters have been used throughout history to improve the safety and aesthetics of water intended to be used for drinking or bathing. In modern times, they are also widely used in industry and commerce. The history of water filtration is closely linked with the broader history of improvements in public health.
