Host factor

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Host factor (sometimes known as risk factor) [1] is a medical term referring to the traits of an individual person or animal that affect susceptibility to disease, especially in comparison to other individuals. [2] The term arose in the context of infectious disease research, in contrast to "organism factors", such as the virulence and infectivity of a microbe. Host factors that may vary in a population and affect disease susceptibility can be innate or acquired.

Some examples: [1]


The term is now used in oncology and many other medical contexts related to individual differences of disease vulnerability.

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<span class="mw-page-title-main">Disease</span> Abnormal condition that negatively affects an organism

A disease is a particular abnormal condition that negatively affects the structure or function of all or part of an organism, and that 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.

<span class="mw-page-title-main">Phenotype</span> Composite of the organisms observable characteristics or traits

In genetics, the phenotype is the set of observable characteristics or traits of an organism. The term covers the organism's morphology, its developmental processes, its biochemical and physiological properties, its behavior, and the products of behavior. An organism's phenotype results from two basic factors: the expression of an organism's genetic code and the influence of environmental factors. Both factors may interact, further affecting the phenotype. When two or more clearly different phenotypes exist in the same population of a species, the species is called polymorphic. A well-documented example of polymorphism is Labrador Retriever coloring; while the coat color depends on many genes, it is clearly seen in the environment as yellow, black, and brown. Richard Dawkins in 1978 and then again in his 1982 book The Extended Phenotype suggested that one can regard bird nests and other built structures such as caddisfly larva cases and beaver dams as "extended phenotypes".

<span class="mw-page-title-main">Infection</span> Invasion of an organisms body by pathogenic agents

An infection is the invasion of tissues by pathogens, their multiplication, and the reaction of host tissues to the infectious agent and the toxins they produce. An infectious disease, also known as a transmissible disease or communicable disease, is an illness resulting from an infection.

<span class="mw-page-title-main">Pathology</span> Study of the causes and effects of disease or injury, also how they arise

Pathology is the study of the causes and effects of disease or injury. The word pathology also refers to the study of disease in general, incorporating a wide range of biology research fields and medical practices. However, when used in the context of modern medical treatment, the term is often used in a narrower fashion to refer to processes and tests that fall within the contemporary medical field of "general pathology", an area which includes a number of distinct but inter-related medical specialties that diagnose disease, mostly through analysis of tissue and human cell samples. Idiomatically, "a pathology" may also refer to the predicted or actual progression of particular diseases, and the affix pathy is sometimes used to indicate a state of disease in cases of both physical ailment and psychological conditions. A physician practicing pathology is called a pathologist.

<span class="mw-page-title-main">Epidemic</span> Rapid spread of disease affecting a large number of people in a short time

An epidemic is the rapid spread of disease to a large number of patients among a given population within an area in a short period of time.

<span class="mw-page-title-main">Epidemiology</span> Study of health and disease within a population

Epidemiology is the study and analysis of the distribution, patterns and determinants of health and disease conditions in a defined population.

Health, according to the World Health Organization, is "a state of complete physical, mental and social well-being and not merely the absence of disease and infirmity". A variety of definitions have been used for different purposes over time. Health can be promoted by encouraging healthful activities, such as regular physical exercise and adequate sleep, and by reducing or avoiding unhealthful activities or situations, such as smoking or excessive stress. Some factors affecting health are due to individual choices, such as whether to engage in a high-risk behavior, while others are due to structural causes, such as whether the society is arranged in a way that makes it easier or harder for people to get necessary healthcare services. Still, other factors are beyond both individual and group choices, such as genetic disorders.

<span class="mw-page-title-main">Stress (biology)</span> Organisms response to a stressor such as an environmental condition or a stimulus

Stress, either physiological, biological or psychological, is an organism's response to a stressor such as an environmental condition. Stress is the body's method of reacting to a condition such as a threat, challenge or physical and psychological barrier. There are two hormones that an individual produces during a stressful situation, these are well known as adrenaline and cortisol. There are two kinds of stress hormone levels. Resting (basal) cortisol levels are normal everyday quantities that are essential for standard functioning. Reactive cortisol levels are increases in cortisol in response to stressors. Stimuli that alter an organism's environment are responded to by multiple systems in the body. In humans and most mammals, the autonomic nervous system and hypothalamic-pituitary-adrenal (HPA) axis are the two major systems that respond to stress.

<span class="mw-page-title-main">Environmental health</span> Public health branch focused on environmental impacts on human health

Environmental health is the branch of public health concerned with all aspects of the natural and built environment affecting human health. In order to effectively control factors that may affect health, the requirements that must be met in order to create a healthy environment must be determined. Environmental health focuses on the natural and built environments for the benefit of human health. The major sub-disciplines of environmental health are environmental science, toxicology, environmental epidemiology, and environmental and occupational medicine.

Virulence is a pathogen's or microorganism's ability to cause damage to a host.

<span class="mw-page-title-main">Exotoxin</span> Toxin from bacteria that destroys or disrupts cells

An exotoxin is a toxin secreted by bacteria. An exotoxin can cause damage to the host by destroying cells or disrupting normal cellular metabolism. They are highly potent and can cause major damage to the host. Exotoxins may be secreted, or, similar to endotoxins, may be released during lysis of the cell. Gram negative pathogens may secrete outer membrane vesicles containing lipopolysaccharide endotoxin and some virulence proteins in the bounding membrane along with some other toxins as intra-vesicular contents, thus adding a previously unforeseen dimension to the well-known eukaryote process of membrane vesicle trafficking, which is quite active at the host–pathogen interface.

An environmental factor, ecological factor or eco factor is any factor, abiotic or biotic, that influences living organisms. Abiotic factors include ambient temperature, amount of sunlight, and pH of the water soil in which an organism lives. Biotic factors would include the availability of food organisms and the presence of biological specificity, competitors, predators, and parasites.

<span class="mw-page-title-main">Diathesis–stress model</span> Psychological theory

The diathesis-stress model, also known as the vulnerability–stress model, is a psychological theory that attempts to explain a disorder, or its trajectory, as the result of an interaction between a predispositional vulnerability, the diathesis, and stress caused by life experiences. The term diathesis derives from the Greek term (διάθεσις) for a predisposition or sensibility. A diathesis can take the form of genetic, psychological, biological, or situational factors. A large range of differences exists among individuals' vulnerabilities to the development of a disorder.

<span class="mw-page-title-main">Asepsis</span> Absence of disease-causing microorganisms

Asepsis is the state of being free from disease-causing micro-organisms. There are two categories of asepsis: medical and surgical. The modern day notion of asepsis is derived from the older antiseptic techniques, a shift initiated by different individuals in the 19th century who introduced practices such as the sterilizing of surgical tools and the wearing of surgical gloves during operations. The goal of asepsis is to eliminate infection, not to achieve sterility. Ideally, a surgical field is sterile, meaning it is free of all biological contaminants, not just those that can cause disease, putrefaction, or fermentation. Even in an aseptic state, a condition of sterile inflammation may develop. The term often refers to those practices used to promote or induce asepsis in an operative field of surgery or medicine to prevent infection.

<span class="mw-page-title-main">Gene–environment interaction</span> Response to the same environmental variation differently by different genotypes

Gene–environment interaction is when two different genotypes respond to environmental variation in different ways. A norm of reaction is a graph that shows the relationship between genes and environmental factors when phenotypic differences are continuous. They can help illustrate GxE interactions. When the norm of reaction is not parallel, as shown in the figure below, there is a gene by environment interaction. This indicates that each genotype responds to environmental variation in a different way. Environmental variation can be physical, chemical, biological, behavior patterns or life events.

Public health genomics is the use of genomics information to benefit public health. This is visualized as more effective preventive care and disease treatments with better specificity, tailored to the genetic makeup of each patient. According to the Centers for Disease Control and Prevention (U.S.), Public Health genomics is an emerging field of study that assesses the impact of genes and their interaction with behavior, diet and the environment on the population's health.

<span class="mw-page-title-main">Disease vector</span> Agent that carries and transmits an infectious pathogen into another living organism

In epidemiology, a disease vector is any living agent that carries and transmits an infectious pathogen to another living organism; agents regarded as vectors are organisms, such as parasites or microbes. The first major discovery of a disease vector came from Ronald Ross in 1897, who discovered the malaria pathogen when he dissected a mosquito.

The differential susceptibility theory proposed by Jay Belsky is another interpretation of psychological findings that are usually discussed according to the diathesis-stress model. Both models suggest that people's development and emotional affect are differentially affected by experiences or qualities of the environment. Where the Diathesis-stress model suggests a group that is sensitive to negative environments only, the differential susceptibility hypothesis suggests a group that is sensitive to both negative and positive environments. A third model, the vantage-sensitivity model, suggests a group that is sensitive to positive environments only. All three models may be considered complementary, and have been combined into a general environmental sensitivity framework.

<span class="mw-page-title-main">Alcoholic lung disease</span> Human disease

Alcoholic lung disease is disease of the lungs caused by excessive alcohol. The term 'alcoholic lung disease' is not a generally accepted medical diagnosis, and "the association between alcohol abuse and acute lung injury remains largely unrecognized, even by lung researchers".

Occupational toxicology is the application of toxicology to chemical hazards in the workplace. It focuses on substances and conditions that occur in workplaces, where inhalation exposure and dermal exposure are most important, there is often exposure to mixtures of chemicals whose interactions are complex, health effects are influenced or confounded by other environmental and individual factors, and there is a focus on identifying early adverse affects that are more subtle than those presented in clinical medicine.

References

  1. 1 2 "Principles of Epidemiology | Lesson 1 - Section 8". www.cdc.gov. 2021-12-20. Retrieved 2023-01-30.
  2. "Host factors". TheFreeDictionary.com. Retrieved 2023-01-30.