A report on Disease

Scanning electron micrograph of Mycobacterium tuberculosis, a species of pathogenic bacteria that cause tuberculosis
This rash only affects one part of the body, so it is a localized disease.
Regular physical activity, such as riding a bicycle or walking, reduces the risk of lifestyle diseases.
Obesity was a status symbol in Renaissance culture: "The Tuscan General Alessandro del Borro", attributed to Andrea Sacchi, 1645. It is now generally regarded as a disease.

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.

- Disease
Scanning electron micrograph of Mycobacterium tuberculosis, a species of pathogenic bacteria that cause tuberculosis

78 related topics with Alpha

Overall

False-colored electron micrograph showing a malaria sporozoite migrating through the midgut epithelium of a rat

Infection

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Invasion of tissues by pathogens, their multiplication, and the reaction of host tissues to the infectious agent and the toxins they produce.

Invasion of tissues by pathogens, their multiplication, and the reaction of host tissues to the infectious agent and the toxins they produce.

False-colored electron micrograph showing a malaria sporozoite migrating through the midgut epithelium of a rat
Chain of infection; the chain of events that lead to infection
Infection of an ingrown toenail; there is pus (yellow) and resultant inflammation (redness and swelling around the nail).
This image depicts the steps of pathogenic infection.
A southern house mosquito (Culex quinquefasciatus) is a vector that transmits the pathogens that cause West Nile fever and avian malaria among others.
Four nutrient agar plates growing colonies of common Gram negative bacteria.
Nucleic acid testing conducted using an Abbott Laboratories ID Now device
A temporary drive-in testing site for COVID-19 set up with tents in a parking lot
Washing one's hands, a form of hygiene, is an effective way to prevent the spread of infectious disease.
Mary Mallon (a.k.a. Typhoid Mary) was an asymptomatic carrier of typhoid fever. Over the course of her career as a cook, she infected 53 people, three of whom died.
Deaths due to infectious and parasitic diseases per million persons in 2012
Great Plague of Marseille in 1720 killed 100,000 people in the city and the surrounding provinces
East German postage stamps depicting four antique microscopes. Advancements in microscopy were essential to the early study of infectious diseases.
Herrerasaurus skull.
Disability-adjusted life year for infectious and parasitic diseases per 100,000 inhabitants in 2004. 
no data
≤250
250–500
500–1000
1000–2000
2000–3000
3000–4000
4000–5000
5000–6250
6250–12,500
12,500–25,000
25,000–50,000
≥50,000

An infectious disease, also known as a transmissible disease or communicable disease, is an illness resulting from an infection.

Signs including (enlarged liver and spleen), and symptoms (including headache, and vomiting) of acute HIV infection.

Signs and symptoms

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Signs including (enlarged liver and spleen), and symptoms (including headache, and vomiting) of acute HIV infection.
Painting of René Laennec in 1816 using an early method of auscultation on a man with tuberculosis.

Signs and symptoms are the observed or detectable signs, and experienced symptoms of an illness, injury, or condition.

A scanning electron microscope image of a single neutrophil (yellow/right), engulfing anthrax bacteria (orange/left) – scale bar is 5 µm (false color)

Immune system

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A scanning electron microscope image of a single neutrophil (yellow/right), engulfing anthrax bacteria (orange/left) – scale bar is 5 µm (false color)
A scanning electron microscope image of normal circulating human blood. One can see red blood cells, several knobby white blood cells including lymphocytes, a monocyte, a neutrophil, and many small disc-shaped platelets.
Overview of the processes involved in the primary immune response
An antibody is made up of two heavy chains and two light chains. The unique variable region allows an antibody to recognize its matching antigen.
The time-course of an immune response begins with the initial pathogen encounter, (or initial vaccination) and leads to the formation and maintenance of active immunological memory.
Joints of a hand swollen and deformed by rheumatoid arthritis, an autoimmune disorder
Skeletal structural formula of the immunosuppressive drug dexamethasone
Polio vaccination in Egypt
Macrophages have identified a cancer cell (the large, spiky mass). Upon fusing with the cancer cell, the macrophages (smaller white cells) inject toxins that kill the tumor cell. Immunotherapy for the treatment of cancer is an active area of medical research.
Paul Ehrlich (1854–1915) was awarded a Nobel Prize in 1908 for his contributions to immunology.

The immune system is a network of biological processes that protects an organism from diseases.

Example of historical public health recommendations from 1918 in New Haven, Connecticut, United States

Public health

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Public health has been defined as "the science and art of preventing disease, prolonging life and promoting health through the organized efforts and informed choices of society, organizations, public and private, communities and individuals".

Public health has been defined as "the science and art of preventing disease, prolonging life and promoting health through the organized efforts and informed choices of society, organizations, public and private, communities and individuals".

Example of historical public health recommendations from 1918 in New Haven, Connecticut, United States
Community health workers
The WHO is the predominant agency associated with global health
Newspaper headlines from around the world about polio vaccine tests (13 April 1955)
Three former directors of the Global Smallpox Eradication Program reading the news that smallpox had been globally eradicated, 1980
A village health worker in Zimbabwe conducting a pediatric examination
A community health worker in Korail Basti, a slum in Dhaka, Bangladesh
A malaria test in Kenya. Despite being preventable and curable, malaria is a leading cause of death in many developing nations.
A Cuban doctor performs an open air operation in Guinea-Bissau. Cuba sends more medical personnel to the developing world than all G8 countries combined.
Mass burials during the second plague pandemic (a.k.a. the Black Death; 1346–1353) intensified urban responses to disaster on the basis of earlier practices. Miniature from "The Chronicles of Gilles Li Muisis" (1272–1352). Bibliothèque royale de Belgique, MS 13076–77, f. 24v.
A depiction of Aztec smallpox victims
Sir Edwin Chadwick was a pivotal influence on the early public health campaign.
Early epidemiologist John Snow mapped clusters of cholera cases in London
Paul-Louis Simond injecting a plague vaccine in Karachi, 1898
The London School of Hygiene & Tropical Medicine is the oldest school of public health in the Anglosphere
Ghanaian children receive insecticide-treated bed nets to prevent exposure to malaria transmitting mosquitos

From the beginnings of human civilization, communities promoted health and fought disease at the population level.

A coronal CT scan showing a malignant mesothelioma
Legend: → tumor ←, ✱ central pleural effusion, 1 & 3 lungs, 2 spine, 4 ribs, 5 aorta, 6 spleen, 7 & 8 kidneys, 9 liver

Cancer

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A coronal CT scan showing a malignant mesothelioma
Legend: → tumor ←, ✱ central pleural effusion, 1 & 3 lungs, 2 spine, 4 ribs, 5 aorta, 6 spleen, 7 & 8 kidneys, 9 liver
Symptoms of cancer metastasis depend on the location of the tumor.
The GHS Hazard pictogram for carcinogenic substances
Share of cancer deaths attributed to tobacco in 2016.
The incidence of lung cancer is highly correlated with smoking.
Cancers are caused by a series of mutations. Each mutation alters the behavior of the cell somewhat.
The central role of DNA damage and epigenetic defects in DNA repair genes in carcinogenesis
Chest X-ray showing lung cancer in the left lung
Three measures of global cancer mortality from 1990 to 2017
Engraving with two views of a Dutch woman who had a tumor removed from her neck in 1689
University of Florida Cancer Hospital
CancerTreeMammal
An invasive ductal carcinoma of the breast (pale area at the center) surrounded by spikes of whitish scar tissue and yellow fatty tissue
An invasive colorectal carcinoma (top center) in a colectomy specimen
A squamous-cell carcinoma (the whitish tumor) near the bronchi in a lung specimen
A large invasive ductal carcinoma in a mastectomy specimen

Cancer is a group of diseases involving abnormal cell growth with the potential to invade or spread to other parts of the body.

Headquarters in Geneva

World Health Organization

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Specialized agency of the United Nations responsible for international public health.

Specialized agency of the United Nations responsible for international public health.

Headquarters in Geneva
Headquarters in Geneva
Alexey Yablokov (left) and Vassili Nesterenko (farthest right) protesting in front of the World Health Organization headquarters in Geneva, Switzerland in 2008.
Demonstration on Chernobyl disaster day near WHO in Geneva
Three former directors of the Global Smallpox Eradication Programme read the news that smallpox had been globally eradicated, 1980
Countries by World Health Organization membership status
Stairwell, 1969
Internal courtyard, 1969
Reflecting pool, 1969
Exterior, 1969
From Southwest, 2013
Entrance hall, 2013
Main conference room, 2013
Map of the WHO's regional offices and their respective operating regions.
Africa; HQ: Brazzaville, Republic of the Congo
Western Pacific; HQ: Manila, Philippines
Eastern Mediterranean; HQ: Cairo, Egypt
South East Asia; HQ: New Delhi, India
Europe; HQ: Copenhagen, Denmark
Americas; HQ: Washington, D.C., US

WHO works to "reduce morbidity and mortality and improve health during key stages of life, including pregnancy, childbirth, the neonatal period, childhood and adolescence, and improve sexual and reproductive health and promote active and healthy aging for all individuals".

Chronic condition

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A chronic condition is a health condition or disease that is persistent or otherwise long-lasting in its effects or a disease that comes with time.

CT scan of the brain showing a prior right-sided ischemic stroke from blockage of an artery. Changes on a CT may not be visible early on.

Stroke

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CT scan of the brain showing a prior right-sided ischemic stroke from blockage of an artery. Changes on a CT may not be visible early on.
There are two main categories of strokes. Ischemic (top), typically caused by a blood clot in an artery (1a) resulting in brain death to the affected area (2a). Hemorrhagic (bottom), caused by blood leaking into or around the brain from a ruptured blood vessel (1b) allowing blood to pool in the affected area (2b) thus increasing the pressure on the brain.
A slice of brain from the autopsy of a person who had an acute middle cerebral artery (MCA) stroke
CT scan of an intraparenchymal bleed (bottom arrow) with surrounding edema (top arrow)
Illustration of an embolic stroke, showing a blockage lodged in a blood vessel.
Histopathology at high magnification of a normal neuron, and an ischemic stroke at approximately 24 hours on H&E stain: The neurons become hypereosinophilic and there is an infiltrate of neutrophils. There is slight edema and loss of normal architecture in the surrounding neuropil.
A CT showing early signs of a middle cerebral artery stroke with loss of definition of the gyri and grey white boundary
Dens media sign in a patient with middle cerebral artery infarction shown on the left. Right image after 7 hours.
12-lead ECG of a patient with a stroke, showing large deeply inverted T-waves. Various ECG changes may occur in people with strokes and other brain disorders.
Walking with an orthosis after a stroke
Stroke deaths per million persons in 2012
Hippocrates first described the sudden paralysis that is often associated with stroke.

A stroke is a medical condition in which poor blood flow to the brain causes cell death.

A pathologist examines a tissue section for evidence of cancerous cells while a surgeon observes.

Pathology

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A pathologist examines a tissue section for evidence of cancerous cells while a surgeon observes.
The advent of the microscope was one of the major developments in the history of pathology. Here researchers at the Centers for Disease Control in 1978 examine cultures containing Legionella pneumophila, the pathogen responsible for Legionnaire's disease.
A modern pathology lab at the Services Institute of Medical Sciences
A bone marrow smear from a case of erythroleukemia. The large cell in the top center is an abnormal erythroblast: it is multinucleated, with megaloblastoid nuclear chromatin This is diagnostic of erythroleukemia.
A malignant melanoma can often be suspected from sight, but confirmation of the diagnosis or outright removal requires an excisional biopsy.
Pathologist performing a human dissection of the abdominal and thoracic organs in an autopsy room
An instance of diagnosis via histopathology, this high-magnification micrograph of a section of cardiac tissue reveals advanced cardiac amyloidosis. This sample was attained through an autopsy.
This coronal cross-section of a brain reveals a significant arteriovenous malformation that occupies much of the parietal lobe.
This tissue cross-section demonstrates the gross pathology of polycystic kidneys.
Brain biopsy under stereotaxy. A small part of the tumor is taken via a needle with a vacuum system.
Clinical chemistry: an automated blood chemistry analyzer
Many conditions, such as this case of geographic tongue, can be diagnosed partly on gross examination, but may be confirmed with tissue pathology.
An anatomical pathology instructor uses a microscope with multiple eyepieces to instruct students in diagnostic microscopy.
This field post-mortem of a ewe has revealed lesions consistent with acute haemolytic pneumonia, possibly due to Pasteurella haemolytica.
A tobacco plant infected with the tobacco mosaic virus

Pathology is the study of the causes and effects of disease or injury.

A photomicrograph of a stool that has shigella dysentery. This bacteria typically causes foodborne illness.

Pathogen

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A photomicrograph of a stool that has shigella dysentery. This bacteria typically causes foodborne illness.
Magnified 100× and stained. This photomicrograph of the brain tissue shows the presence of the prominent spongiotic changes in the cortex, with the loss of neurons in a case of a variant of Creutzfeldt-Jakob disease (vCJD)
Two pinworms next to a ruler, measuring in 6 millimeters in length
Brown rot fungal disease on an apple. Brown rot typically target a variety of top-fruits.
A structure of Doxycycline a tetracycline-class antibiotic

In biology, a pathogen (πάθος, "suffering", "passion" and -γενής, "producer of") in the oldest and broadest sense, is any organism or agent that can produce disease.