Disease
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.
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 this broader sense, it sometimes includes injuries, disabilities, disorders, syndromes, infections, isolated symptoms, deviant behaviors, and atypical variations of structure and function, while in other contexts and for other purposes these may be considered distinguishable categories.
The latency period is the time between infection and the ability of the disease to spread to another person, which may precede, follow, or be simultaneous with the appearance of symptoms.
Classical classification of human disease derives from the observational correlation between pathological analysis and clinical syndromes.
The microorganisms that cause these diseases are known as pathogens and include varieties of bacteria, viruses, protozoa, and fungi.
For example, until the bacterial cause of tuberculosis was discovered in 1882, experts variously ascribed the disease to heredity, a sedentary lifestyle, depressed mood, and overindulgence in sex, rich food, or alcohol, all of which were social ills at the time.
These include sanitation, proper nutrition, adequate exercise, vaccinations and other self-care and public health measures, such as obligatory face mask mandates[citation needed].
Epidemiology is considered a cornerstone methodology of public health research and is highly regarded in evidence-based medicine for identifying risk factors for diseases.
In the study of communicable and non-communicable diseases, the work of epidemiologists ranges from outbreak investigation to study design, data collection, and analysis including the development of statistical models to test hypotheses and the documentation of results for submission to peer-reviewed journals.
Epidemiologists rely on a number of other scientific disciplines such as biology (to better understand disease processes), biostatistics (the current raw information available), Geographic Information Science (to store data and map disease patterns) and social science disciplines (to better understand proximate and distal risk factors).
[37] Some morbidity databases are compiled with data supplied by states and territories health authorities, at national levels[38][39] or larger scale (such as European Hospital Morbidity Database (HMDB))[40] which may contain hospital discharge data by detailed diagnosis, age and sex.
Disease burden is the impact of a health problem in an area measured by financial cost, mortality, morbidity, or other indicators.
In 2004, the World Health Organization calculated that 932 million years of potential life were lost to premature death.
Unlike YPLL, these measurements show the burden imposed on people who are very sick, but who live a normal lifespan.
In 2004, the World Health Organization calculated that 1.5 billion disability-adjusted life years were lost to disease and injury.
A person who responds to a dreaded disease, such as cancer, in a culturally acceptable fashion may be publicly and privately honored with higher social status.
As a comparison, consider pregnancy, which is not interpreted as a disease or sickness, even if the mother and baby may both benefit from medical care.
For example, one whose life would be endangered by fasting on Yom Kippur or during the month of Ramadan is exempted from the requirement, or even forbidden from participating.
[48] The identification of a condition as a disease, rather than as simply a variation of human structure or function, can have significant social or economic implications.
Some diseases, such as diabetes mellitus, may be associated with both poverty (poor food choices) and affluence (long lifespans and sedentary lifestyles), through different mechanisms.
The most popular metaphors draw on military concepts: Disease is an enemy that must be feared, fought, battled, and routed.
Because the threat is urgent, perhaps a matter of life and death, unthinkably radical, even oppressive, measures are society's and the patient's moral duty as they courageously mobilize to struggle against destruction.
[49][50] Some are explicitly immigration-themed: the patient has been exiled from the home territory of health to the land of the ill, changing identity and relationships in the process.
[49] Some diseases are used as metaphors for social ills: "Cancer" is a common description for anything that is endemic and destructive in society, such as poverty, injustice, or racism.
People with the disease were portrayed in literature as having risen above daily life to become ephemeral objects of spiritual or artistic achievement.
