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Contagious Disease
A contagious disease is an infectious disease that can be spread rapidly in several ways, including direct contact, indirect contact, and droplet contact. These diseases are caused by organisms such as parasites, bacteria, fungi, and viruses. While many types of organisms live on the human body and are usually harmless, these organisms can sometimes cause disease. Some common infectious diseases are influenza, COVID-19, ebola, hepatitis, HIV/AIDS, Human papillomavirus infection, Polio, and Zika virus. A disease is often known to be contagious before medical science discovers its causative agent. Koch's postulates, which were published at the end of the 19th century, were the standard for the next 100 years or more, especially with diseases caused by bacteria. Microbial pathogenesis attempts to account for diseases caused by a virus. Historical meaning Originally, the term referred to a ''contagion'' or disease transmissible only by direct physical contact. In the mode ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Coughs And Sneezes Spread Diseases Art
A cough is a sudden expulsion of air through the large breathing passages which can help clear them of fluids, irritants, foreign particles and Microorganism, microbes. As a protective reflex, coughing can be repetitive with the cough reflex following three phases: an inhalation, a forced exhalation against a closed glottis, and a violent release of air from the lungs following opening of the glottis, usually accompanied by a distinctive sound. Coughing into one's elbow or toward the ground—rather than forward at breathing height—can reduce the spread of infectious droplets in the air. Frequent coughing usually indicates the presence of a disease. Many viruses and bacteria benefit, from an evolutionary perspective, by causing the Host (biology), host to cough, which helps to spread the disease to new hosts. Irregular coughing is usually caused by a respiratory tract infection but can also be triggered by choking, smoking, air pollution, asthma, gastroesophageal reflux disease ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Koch's Postulates
Koch's postulates ( ) are four criteria designed to establish a causality, causal relationship between a microbe and a disease. The postulates were formulated by Robert Koch and Friedrich Loeffler in 1884, based on earlier concepts described by Jakob Henle, and the statements were refined and published by Koch in 1890. Koch applied the postulates to describe the etiology of cholera and tuberculosis, both of which are now ascribed to bacteria. The postulates have been controversially generalized to other diseases. More modern concepts in microbial pathogenesis cannot be examined using Koch's postulates, including viruses (which are Obligate parasite, obligate intracellular parasites) and asymptomatic carriers. They have largely been supplanted by other criteria such as the Bradford Hill criteria for infectious disease causality in Public health#Current practice, modern public health and the Molecular Koch's postulates for microbial pathogenesis. Postulates Koch's four postulates ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Notifiable Disease
A notifiable disease is any disease that is required by law to be reported to government authorities. The collation of information allows the authorities to monitor the disease, and provides early warning of possible outbreaks. In the case of livestock diseases, there may also be the legal requirement to kill the infected livestock upon notification. Many governments have enacted regulations for reporting of both human and animal (generally livestock) diseases. Global Human The World Health Organization's ''International Health Regulations 1969'' require disease reporting to the organization in order to help with its global surveillance and advisory role. The current (1969) regulations are rather limited with a focus on reporting of three main diseases: cholera, yellow fever and plague. Smallpox was a contagious disease during the 18th-20th century. It was endemic until mass vaccination, after which WHO certified Smallpox to be eradicated. This marked the first (and thus ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Herd Immunity
Herd immunity (also called herd effect, community immunity, population immunity, or mass immunity) is a form of indirect protection that applies only to contagious diseases. It occurs when a sufficient percentage of a population has become immune to an infection, whether through previous infections or vaccination, that the communicable pathogen cannot maintain itself in the population, its low incidence thereby reducing the likelihood of infection for individuals who lack immunity. Once the herd immunity has been reached, disease gradually disappears from a population and may result in eradication or permanent reduction of infections to zero if achieved worldwide. Herd immunity created via vaccination has contributed to the reduction of many diseases. Effects Protection of those without immunity Some individuals either cannot develop immunity after vaccination or for medical reasons cannot be vaccinated. Newborn infants are too young to receive many vaccines, either for sa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Germ Theory Of Disease
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 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. 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-causing agents that can pass from one individual to another, across multiple domains of life. Basic forms of germ theory were proposed by Girolamo Fracastoro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aerobiological Engineering
Aerobiological engineering is the science of designing buildings and systems to control airborne pathogens and allergens in indoor environments. The most-common environments include commercial buildings, residences and hospitals. This field of study is important because controlled indoor climates generally tend to favor the survival and transmission of contagious human pathogens as well as certain kinds of fungi and bacteria. Aerobiological engineering in healthcare facilities Since healthcare facilities can house a number of different types of patients who potentially have weakened immune systems, aerobiological engineering is of significant importance to engineers of hospitals. The aerobiology that concerns designers of hospitals includes viruses, bacteria, fungi, and other microbiological products such as endotoxins, mycotoxins, and microbial volatile organic compounds (MVOC's). Bacteria and viruses, because of their small size, readily become airborne as bacterial aeros ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Negative Room Pressure
Negative room pressure is an isolation technique used in hospitals and medical centers to prevent cross-contamination from room to room.Negative Room Pressure to Prevent Cross-Contamination Clean Air Solutions, Camil Farr, Retrieved 2010-03-10. It includes a that generates (pressure lower than that of the surroundings) to allow air to flow into the isolation room but not escape from the room, as air will naturally ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Basic Reproduction Number
In epidemiology, the basic reproduction number, or basic reproductive number (sometimes called basic reproduction ratio or basic reproductive rate), denoted R_0 (pronounced ''R nought'' or ''R zero''), of an infection is the expected number of cases directly generated by one case in a population where all individuals are susceptible to infection. The definition assumes that no other individuals are infected or immunized (naturally or through vaccination). Some definitions, such as that of the Australian Department of Health, add the absence of "any deliberate intervention in disease transmission". The basic reproduction number is not necessarily the same as the effective reproduction number R (usually written R_t 't'' for "time" sometimes R_e), which is the number of cases generated in the current state of a population, which does not have to be the uninfected state. R_0 is a dimensionless number (persons infected per person infecting) and not a time rate, which would have ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Quarantine
A quarantine is a restriction on the movement of people, animals, and goods which is intended to prevent the spread of disease or pests. It is often used in connection to disease and illness, preventing the movement of those who may have been exposed to a communicable disease, yet do not have a confirmed medical diagnosis. It is distinct from medical isolation, in which those confirmed to be infected with a communicable disease are isolated from the healthy population. The concept of quarantine has been known since biblical times, and is known to have been practised through history in various places. Notable quarantines in modern history include the village of Eyam in 1665 during the bubonic plague outbreak in England; East Samoa during the 1918 flu pandemic; the Diphtheria outbreak during the 1925 serum run to Nome, the 1972 Yugoslav smallpox outbreak, the SARS pandemic, the Ebola pandemic and extensive quarantines applied throughout the world during the COVID-19 pande ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Epidemics
An epidemic (from Ancient Greek, Greek ἐπί ''epi'' "upon or above" and δῆμος ''demos'' "people") is the rapid spread of disease to a large number of Host (biology), hosts in a given population within a short period of time. For example, in meningococcal infections, an attack rate in excess of 15 cases per 100,000 people for two consecutive weeks is considered an epidemic. Epidemics of infectious disease are generally caused by several factors including a change in the ecology of the host population (e.g., increased stress or increase in the density of a vector species), a genetic change in the pathogen reservoir or the introduction of an emerging pathogen to a host population (by movement of pathogen or host). Generally, an epidemic occurs when host Immunity (medicine), immunity to either an established pathogen or newly emerging novel pathogen is suddenly reduced below that found in the Endemic (epidemiology), endemic equilibrium and the transmission threshold is excee ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
NIH Clinical Center - Special Clinical Studies Unit
The National Institutes of Health (NIH) is the primary agency of the United States government responsible for biomedical and public health research. It was founded in 1887 and is part of the United States Department of Health and Human Services (HHS). Many NIH facilities are located in Bethesda, Maryland, and other nearby suburbs of the Washington metropolitan area, with other primary facilities in the Research Triangle Park in North Carolina and smaller satellite facilities located around the United States. The NIH conducts its scientific research through the NIH Intramural Research Program (IRP) and provides significant biomedical research funding to non-NIH research facilities through its Extramural Research Program. , the IRP had 1,200 principal investigators and more than 4,000 postdoctoral fellows in basic, translational, and clinical research, being the largest biomedical research institution in the world, while, as of 2003, the extramural arm provided 28% of biomedical ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
