Biological Warfare Glossary of Medical Terms

Abdominal: Relating to the abdomen, the belly , that part of the body that contains all of the structures between the chest and the pelvis . The abdomen is separated anatomically from the chest by the diaphragm , the powerful muscle spanning the body cavity below the lungs .
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Abdominal pain: Pain in the belly (the abdomen). Abdominal pain can come from conditions affecting a variety of organs. The abdomen is an anatomical area that is bounded by the lower margin of the ribs above, the pelvic bone (pubic ramus) below, and the flanks on each side. Although abdominal pain can arise from the tissues of the abdominal wall that surround the abdominal cavity (the skin and abdominal wall muscles), the term abdominal pain generally is used to describe pain originating from organs within the abdominal cavity (from beneath the skin and muscles). These organs include the stomach, small intestine, colon, liver, gallbladder, and pancreas.
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Activated charcoal: Charcoal that has been heated to increase its absorptive capacity. Activated charcoal is sold as an over-the-counter (OTC) product to help relieve intestinal gas . It is also used to absorb poisons (as in gas mask filters), neutralize poisons that have been swallowed, and filter and purify liquids.
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Acute: Of abrupt onset, in reference to a disease. Acute often also connotes an illness that is of short duration, rapidly progressive, and in need of urgent care.
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Aerosol: 1. In general, a fine mist or spray which contains minute particles.
2. In medicine, a spray administered by a nebulizer and inhaled for treatment.
3. In medicine, a mist that causes disease as, for example, the hantavirus pulmonary syndrome.
4. In the environment, particles emitted into the air naturally as in volcanic eruptions and through human action such as burning fossil fuel.
5. In the environment, the pressurized gas used to propel substances out of a container.
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Aflatoxin: A toxin produced by mold that can damage the liver and may lead to liver cancer. Aflatoxins cause cancer in some animals.
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Allergic contact dermatitis: A red, itchy, weepy reaction where the skin has come into contact with a substance that the immune system recognizes as foreign, such as poison ivy , poison oak or poison sumac or certain preservatives in creams and lotions. This type of reaction reflects a specific sensitivity or allergy to a specific substance. Also called allergic contact eczema.
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Anthrax : A serious bacterial infection caused by Bacillus anthracis that occurs primarily in animals. Cattle, sheep, horses, mules, and some wild animals are highly susceptible. Humans and swine are generally quite resistant to anthrax. Humans become infected when the spores of B. anthracis enter the body by contact with animals infected with B. anthracis or from contact with contaminated animal products, insect bites, ingestion, or inhalation. Aerosolized ("weaponized") spores of B. anthracis can potentially be used (misused) for biological warfare and bioterrorism. Cutaneous anthrax is the most common form of the disease and is characterized by the development of a localized skin lesion with a central eschar surrounded by marked edema (swelling). Inhalation anthrax (woolsorters' disease) typically involves hemorrhagic mediastinitis (bleeding into the mid-chest), rapidly progressive systemic (bodywide) infection, and carries a very high mortality rate. Gastrointestinal anthrax is much rarer but is also associated with a high mortality rate.
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Antibiotic: A drug used to treat infections caused by bacteria and other microorganisms. Originally, an antibiotic was a substance produced by one microorganism that selectively inhibits the growth of another. Synthetic antibiotics, usually chemically related to natural antibiotics, have since been produced that accomplish comparable tasks.
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Antibody: An immunoglobulin, a specialized immune protein , produced because of the introduction of an antigen into the body, and which possesses the remarkable ability to combine with the very antigen that triggered its production.
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Antitoxin: An antibody capable of destroying microorganisms including viruses and bacteria.
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Antiviral: An agent that kills a virus or that suppresses its ability to replicate and, hence, inhibits its capability to multiply and reproduce.
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Antiviral agent: An agent that kills viruses or suppresses their replication and, hence, inhibits their capability to multiply and reproduce.
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Arenaviridae: See: Arenavirus .
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Arenavirus: One of a family of viruses called Arenaviridae whose members are generally associated with diseases transmitted by rodents to humans. Each arenavirus is usually associated with a particular rodent host species in which it is maintained. Arenavirus infections are relatively common in humans in some areas of the world and can cause severe illnesses.
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Arm: 1. In popular usage, the appendage that extends from the shoulder to the hand. However, the medical definition refers to the upper extremity extending from the shoulder only to the elbow, excluding the forearm, which extends from the elbow to the wrist. The arm contains one bone: the humerus. 2. In a randomized clinical trial, any of the treatment groups. Most randomized trials have two "arms," but some have three "arms," or even more.
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Arms: An appendage in anatomy and in clinical trials . See: Arm .
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Aspirin: A good example of a tradename that entered into the language, Aspirin was once the Bayer trademark for acetylsalicylic acid .
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Assay: An assay is an analysis done to determine:

1. The presence of a substance and the amount of that substance. Thus, an assay may be done for example to determine the level of thyroid hormones in the blood of a person suspected of being hypothyroid (or hyperthyroid).
2. The biological or pharmacological potency of a drug. For example, an assay may be done of a vaccine to determine its potency.

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Bacillus: A large family of bacteria that have a rod-like shape. They include the bacteria that cause food to spoil, and also those responsible for some types of diseases. Helpful members of the bacillus family are used to make antibiotics, or colonize the human intestinal tract and aid with digestion.
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Bacillus anthracis: The bacterium that causes anthrax . Anthrax differs from most bacteria in that they exist in an inactive (dormant) state called spores. The spores are found in soil, animal carcasses and feces (including sheep, goats, cattle, bison, horses, and deer), and animal products (e.g., hides and wool). Some animals (cats, dogs, rats, and swine) are very resistant to anthrax. Remarkably, anthrax spores can remain dormant in soil for many years, perhaps decades. Likened somewhat to eggs that have the ability to hatch, spores can transform (germinate) into active bacteria under appropriate conditions.
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Back pain: Pain felt in the low or upper back. There are many causes of back pain.
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Bacteria: Single-celled microorganisms which can exist either as independent (free-living) organisms or as parasites (dependent upon another organism for life).
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Bacterium: The singular of bacteria .
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Biochemical: Relating to biochemistry, the application of the tools and concepts of chemistry to living systems.
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Biopsy: The removal of a sample of tissue for purposes of diagnosis. (Many definitions of "biopsy" stipulate that the sample of tissue is removed for examination under a microscope. This may or may not be the case. The diagnosis may be achieved by other means such as by analysis of chromosomes or genes.)
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Bioterrorism: Terrorism using biologic agents. Biological diseases and the agents that might be used for terrorism have been listed by the US Centers for Disease Control and Prevention (the CDC ). The list includes a sizable number of "select agents" -- potential weapons whose transfer in the scientific and medical communities is regulated to keep them out of unfriendly hands.
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BLAST: Abbreviation for Basic Local Alignment Search Tool, a computer program that identifies homologous genes in different organisms (such as worms, the fruit fly, mice, and humans). Homologous genes are genes in different species that share similar structures and functions.
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Blood: The familiar red fluid in the body that contains white and red blood cells , platelets , proteins , and other elements. The blood is transported throughout the body by the circulatory system . Blood functions in two directions: arterial and venous. Arterial blood is the means by which oxygen and nutrients are transported to tissues while venous blood is the means by which carbon dioxide and metabolic by-products are transported to the lungs and kidneys, respectively, for removal from the body.
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Blood culture: A test designed to detect if microorganisms such as bacteria and fungi are present in blood. A sample of blood obtained using sterile technique is placed in a culture media and incubated in a controlled environment for 1 to 7 days. If microorganisms grow, they can be identified as to type and tested against different antibiotics for proper treatment of the infection. Because microorganisms may only be intermittently present in blood, a series of 3 blood cultures is usually done before the result is considered negative.
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Blood poisoning: The medical term is "septicemia." No matter which of these two terms-blood poisoning or septicemia-you prefer, what is meant is the same thing, namely a "general (systemic) disease that is due to the presence and the persistence of germs (pathogenic microorganisms) or their toxins in the bloodstream." The "germs" can be bacteria (in bacteremia) or any other microscopic agent of infection capable of causing disease in humans. Another term that is very closely related to "blood poisoning" and "septicemia" is "sepsis." "Sepsis" also refers to the presence and persistence of germs or their toxins in the blood but those germs or toxins do not need to be in the blood. They may be in other tissues of the body. Blood poisoning/septicemia and sepsis are often serious. They can sometimes be life threatening diseases calling for urgent and comprehensive care.
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Blood pressure: The blood pressure is the pressure of the blood within the arteries. It is produced primarily by the contraction of the heart muscle . It's measurement is recorded by two numbers. The first ( systolic pressure) is measured after the heart contracts and is highest. The second ( diastolic pressure) is measured before the heart contracts and lowest. A blood pressure cuff is used to measure the pressure. Elevation of blood pressure is called " hypertension ".
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Bloody nose: The nose is a part of the body that is very rich in blood vessels (vascular) and is situated in a vulnerable position on the face. As a result, any trauma to the face can cause bleeding which may be profuse. Nosebleeds can occur spontaneously when the nasal membranes dry out, crust, and crack, as is common in dry climates, or during the winter months when the air is dry and warm from household heaters. People are more susceptible if they are taking medications which prevent normal blood clotting (Coumadin, warfarin , aspirin, or any anti-inflammatory medication). Other predisposing factors include infection, trauma, allergic and non-allergic rhinitis, hypertension, alcohol abuse, and inherited bleeding problems. To stop a nosebleed , you should: 1. Pinch all the soft parts of the nose together between your thumb and index finger. 2. Press firmly toward the face - compressing the pinched parts of the nose against the bones of the face. 3. Hold the nose for at least 5 minutes (timed by the clock). Repeat as necessary until the nose has stopped bleeding. 4. Sit quietly, keeping the head higher than the level of the heart; that is, sit up or lie with the head elevated. Do not lay flat or put your head between your legs. 5. Apply ice (crushed in a plastic bag or washcloth) to nose and cheeks.
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Blurred vision: Lack of sharpness of vision with, as a result, the inability to see fine detail. Blurred vision can occur when a person who wears corrective lens is without them. Blurred vision can also be an important clue to eye disease.
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Bone: Bone is the substance that forms the skeleton of the body. It is composed chiefly of calcium phosphate and calcium carbonate . It also serves as a storage area for calcium, playing a large role in calcium balance in the blood.
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Bone marrow: The soft blood-forming tissue that fills the cavities of bones and contains fat and immature and mature blood cells, including white blood cells, red blood cells, and platelets. Diseases or drugs that affect the bone marrow can affect the total counts of these cells.
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Botulinum toxin: A toxin produced by the bacterium Clostridium botulinum that is the most poisonous biological substance known. Botulinum toxin acts as a neurotoxin . It binds to the nerve ending at the point where the nerve joins a muscle, blocking the release by the nerve of the chemical acetylcholine (the principal neurotransmitter at the neuromuscular junction), preventing the muscle from contracting. The result is weakness and paralysis of the muscle. The muscle atrophies. The blockage of acetylcholine release is irreversible. Function can be recovered by the sprouting of nerve terminals and the formation of new synaptic contacts, which usually takes 2 to 3 months.
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Bowel: Another name for the intestine . The small bowel and the large bowel are the small intestine and large intestine , respectively.
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Brain: That part of the central nervous system that is located within the cranium ( skull ). The brain functions as the primary receiver, organizer and distributor of information for the body. It has two (right and left) halves called "hemispheres."
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Brain swelling: See: Cerebral edema .
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Breathing: The process of respiration, during which air is inhaled into the lungs through the mouth or nose due to muscle contraction, and then exhaled due to muscle relaxation.
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Brucellosis: An infectious disease due to the bacteria Brucella that causes rising and falling (undulant) fevers, sweats, malaise , weakness, anorexia , headache, myalgia (muscle pain) and back pain.
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Buboes: The plural of "bubo".
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Bubonic plague : The most common form of the plague, named for the characteristic buboes -- buboes are enlarged lymph nodes ("swollen glands") -- in the groin which are usually very tender and painful. Lymph nodes may be similarly affected elsewhere such as in the armpits and neck. Common but less specific features of the disease include headache , fever, chills, and weakness.
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Cardiovascular: The circulatory system comprising the heart and blood vessels which carries nutrients and oxygen to the tissues of the body and removes carbon dioxide and other wastes from them.
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CDC: The Centers for Disease Control and Prevention , the US agency charged with tracking and investigating public health trends. The stated mission of the CDC is "To promote health and quality of life by preventing and controlling disease, injury, and disability." The CDC is a part of the U.S. Public Health Services (PHS) under the Department of Health and Human Services (HHS).
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Centers for Disease Control and Prevention: The US agency charged with tracking and investigating public health trends. The stated mission of the Centers for Disease Control and Prevention, commonly called the CDC, is "To promote health and quality of life by preventing and controlling disease, injury, and disability."
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Chest: The area of the body located between the neck and the abdomen . The chest contains the lungs , the heart and part of the aorta . The walls of the chest are supported by the dorsal vertebrae , the ribs , and the sternum .
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Chest pain: There are many causes of chest pain. One is angina which results from inadequate oxygen supply to the heart muscle. Angina can be caused by coronary artery disease or spasm of the coronary arteries. Chest pain can also be due to a heart attack (coronary occlusion) and other important diseases such as, for example, dissection of the aorta and a pulmonary embolism . Do not try to ignore chest pain and "work (or play) though it." Chest pain is a warning to seek medical attention.
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Chest X-ray: Commonly used to detect abnormalities in the lungs, but can also detect abnormalities in the heart, aorta, and the bones of the thoracic area. Metallic objects, such as jewelry are removed from the chest and neck areas for a chest x-ray to avoid interference with x-ray penetration and improve accuracy of the interpretation.
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Chickenpox: A highly infectious viral disease also known medically as varicella -- in many countries, this disease is always called "varicella" -- that causes a blister-like rash, itching, fatigue and fever. The rash crops up first on the face and trunk and can spread over the entire body resulting in 250 to 500 itchy blisters.

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Cholera : A devastating and sometimes lethal disease with intense vomiting and profuse watery diarrhea leading to dehydration which, unless immediately treated, may be fatal.
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Chronic: This important term in medicine comes from the Greek chronos, time and means lasting a long time.
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Circulation: The movement of fluid in a regular or circuitous course. Although the noun "circulation" does not necessarily refer to the circulation of the blood, for all practical purposes today it does. Heart failure is an example of a problem with the circulation.
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Coma: A state of deep unarousable unconsciousness.
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Complication: In medicine, an additional problem that arises following a procedure, treatment or illness and is secondary to it. A complication complicates the situation.
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Condition: The term "condition" has a number of biomedical meanings including the following:

1. An unhealthy state, such as in "this is a progressive condition."
2. A state of fitness, such as "getting into condition."
3. Something that is essential to the occurrence of something else; essentially a "precondition."
4. As a verb: to cause a change in something so that a response that was previously associated with a certain stimulus becomes associated with another stimulus; to condition a person, as in behavioral conditioning.

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Contact dermatitis: A skin condition caused by contact between skin and some substance. Includes irritant contact dermatitis (a rash brought on purely by repeated irritation from a substance such as water causing "dish pan hands") and allergic contact dermatitis (involving a specific sensitivity or allergy to a specific substance such as poison ivy ).
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Contrast: Short for "contrast media." Contrast media are X-ray dyes used to provide contrast, for example, between blood vessels and other tissue.
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Cough: A rapid expulsion of air from the lungs typically in order to clear the lung airways of fluids, mucus, or material. Also called tussis.
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Cowpox: A mild skin disease of milk cows, principally confined to the udder and teats, that may be contracted by people from milking an infected cow. People develop vesicles (blebs) which break and form ulcers on the fingers (sometimes called "milkers nodules"). These usually heal without scarring. Cowpox protects against smallpox and was used by Edward Jenner in 1798 for this purpose to confer immunity against smallpox. Cowpox and smallpox belong to the orthopox family of viruses.
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Cutaneous: Relating to the skin. As, for example, in cutaneous allodynia , a cutaneous papilloma , and cutaneous syndactyly . From the Latin cutis meaning skin.
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Cuts: Severed skin. Washing a cut or scrape with soap and water and keeping it clean and dry is all that is required to care for most wounds. Putting alcohol hydrogen peroxide, and iodine into a wound can delay healing and should be avoided. Seek medical care early if you think that you might need stitches. Any delay can increase the rate of wound infection. Any puncture wound through tennis shoes has a high risk of infection and should be seen by your healthcare professional. Any redness, swelling, increased pain, or pus draining from the wound may indicate an infection that requires professional care.
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Deafness: Deafness is defined by partial or complete hearing loss. Levels of hearing impairment vary from a mild but important loss of sensitivity to a total loss of hearing. Older adults suffer most often from hearing loss. Age-related hearing loss affects 30 to 35 percent of the population between the ages of 65 and 75 years, and 40 percent of the population over the age of 75. The most common cause of hearing loss in children is otitis media, a disorder that affects predominantly infants and young children. A substantial number of hearing impairments are caused by environmental factors such as noise, drugs, and toxins. Many sensorineural hearing losses result from a genetic predisposition.
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Delirium: A sudden state of severe confusion and rapid changes in brain function, sometimes associated with hallucinations and hyperactivity , in which the patient is inaccessible to normal contact. Symptoms may include inability to concentrate and disorganized thinking evidenced by rambling, irrelevant, or incoherent speech. There may be a reduced level of consciousness, sensory misperceptions and illusions, disturbances of sleep, drowsiness, disorientation to time, place, or person, and problems with memory.
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Dementia : Significant loss of intellectual abilities such as memory capacity, severe enough to interfere with social or occupational functioning.
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Dengue: Also known as Dengue fever , an acute mosquito-borne viral illness of sudden onset that usually follows a benign course with headache , fever , prostration, severe joint and muscle pain , swollen glands (lymphadenopathy) and rash . The presence (the "dengue triad") of fever, rash, and headache (and other pains) is particularly characteristic of dengue. Dengue is endemic throughout the tropics and subtropics. It goes by other names including breakbone or dandy fever. Victims of dengue often have contortions due to the intense joint and muscle pain. Hence, the name "breakbone fever." Slaves in the West Indies who contracted dengue were said to have "dandy fever" because of their postures and gait.
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Dengue fever: An acute mosquito- borne viral illness of sudden onset that usually follows a benign course with headache, fever , prostration, severe joint and muscle pain, swollen glands (lymphadenopathy) and rash . The presence (the "dengue triad") of fever, rash, and headache (and other pains) is particularly characteristic of dengue. Dengue fever is endemic throughout the tropics and subtropics. It goes by other names including breakbone or dandy fever. Victims of dengue often have contortions due to the intense joint and muscle pain. Hence, the name "breakbone fever." Slaves in the West Indies who contracted dengue were said to have "dandy fever" because of their postures and gait.
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Depression : An illness that involves the body, mood, and thoughts, that affects the way a person eats and sleeps, the way one feels about oneself, and the way one thinks about things. A depressive disorder is not the same as a passing blue mood. It is not a sign of personal weakness or a condition that can be wished away. People with a depressive disease cannot merely "pull themselves together" and get better. Without treatment, symptoms can last for weeks, months, or years. Appropriate treatment, however, can help most people with depression.
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Dermatitis: Inflammation of the skin, either due to direct contact with an irritating substance, or to an allergic reaction. Symptoms of dermatitis include redness, itching, and in some cases blistering.
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Diagnosis: 1 The nature of a disease ; the identification of an illness. 2 A conclusion or decision reached by diagnosis. The diagnosis is rabies . 3 The identification of any problem. The diagnosis was a plugged IV.
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Diarrhea : A familiar phenomenon with unusually frequent or unusually liquid bowel movements, excessive watery evacuations of fecal material. The opposite of constipation . The word "diarrhea" with its odd spelling is a near steal from the Greek "diarrhoia" meaning "a flowing through." Plato and Aristotle may have had diarrhoia while today we have diarrhea. There are myriad infectious and noninfectious causes of diarrhea.
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Dizziness : Painless head discomfort with many possible causes including disturbances of vision, the brain, balance (vestibular) system of the inner ear, and gastrointestinal system. Dizziness is a medically indistinct term which laypersons use to describe a variety of conditions ranging from lightheadedness, unsteadiness to vertigo.
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Doxycycline : Brand name: Vibramycin. A synthetic broad-spectrum antibiotic derived from tetracycline . Doxycycline is used for many different types of infections, including respiratory tract infections due to Hemophilus influenzae, Streptococcus pneumoniae, or Mycoplasma pneumoniae. It is also used for the treatment of nongonococcal urethritis (due to Ureaplasma), Rocky Mountain spotted fever, typhus, chancroid, cholera , brucellosis, syphilis, and acne .
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Eastern equine encephalitis: Abbreviated EEE. A mosquito-born viral disease. The EEE virus normally is found in freshwater swamp birds and mosquitoes that do not bite people. However, the virus is occasionally transmitted to other types of mosquitoes capable of biting horses and people. The risk of contracting EEE is highest in mid-to-late summer. The mosquitoes are killed by frost.
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Ebola virus: A notoriously deadly virus that causes fearsome symptoms, the most prominent being high fever and massive internal bleeding. Ebola virus kills as many as 90% of the people it infects. It is one of the viruses that is capable of causing hemorrhagic (bloody) fever.
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Eczema: A particular type of inflammatory reaction of the skin in which there are typically vesicles (tiny blister-like raised areas) in the first stage followed by erythema (reddening), edema (swelling), papules (bumps), and crusting of the skin followed, finally, by lichenification (thickening) and scaling of the skin. Eczema characteristically causes itching and burning of the skin.
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ELISA: ELISA stands for "enzyme-linked immunosorbent assay." This is a rapid immunochemical test that involves an enzyme (a protein that catalyzes a biochemical reaction). It also involves an antibody or antigen (immunologic molecules).
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Emergency department: The department of a hospital responsible for the provision of medical and surgical care to patients arriving at the hospital in need of immediate care. Emergency department personnel may also respond to certain situations within the hospital such cardiac arrests.
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Encephalitis: Inflammation of the brain. Encephalitis occurs, for example, in 1 in 1,000 cases of measles . It may start (up to 3 weeks) after onset of the measles rash and present with high fever , convulsions, and coma. It usually runs a blessedly short course with full recovery within a week. Or it may eventuate in central nervous system impairment or death.
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Environment: The sum of the total of the elements, factors and conditions in the surroundings which may have an impact on the development , action or survival of an organism or group of organisms.
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Epidemic: The occurrence of more cases of a disease than would be expected in a community or region during a given time period. A sudden severe outbreak of a disease such as SARS. From the Greek "epi-", "upon" + "demos", "people or population" = "epidemos" = "upon the population." See also: Endemic; Pandemic.
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Erythromycin: Erythromycin is a common antibiotic for treating bacterial infection. Sold under many brand names, including EES, Erycin and Erythromia.
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Event: A set of outcomes. Cardiovascular events might include a heart attack and gastrointestinal events a GI bleed. The use of the term "event" in medicine comes from probability theory.
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Fatigue: A condition characterized by a lessened capacity for work and reduced efficiency of accomplishment, usually accompanied by a feeling of weariness and tiredness. Fatigue can be acute and come on suddenly or chronic and persist.
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Feces: The medical and scientific term for the "excrement discharged from the intestines."
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Feet: The plural of foot, both an anatomic structure and a unit of measure.
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Fever : Although a fever technically is any body temperature above the normal of 98.6 degrees F. (37 degrees C.), in practice a person is usually not considered to have a significant fever until the temperature is above 100.4 degrees F (38 degrees C.).
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Filoviridae: A family of viruses that cause hemorrhagic fever . Filoviruses have single- stranded RNA as their genetic material. Ebola virus and the Marburg virus are both filoviruses.
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Flaviviridae: A family of viruses transmitted by mosquitos and ticks that cause some important diseases, including dengue , yellow fever , tick-borne encephalitis virus, and West Nile fever . The flaviviruses are positive-strand RNA viruses containing three structural proteins and a host-derived lipid bilayer.
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Food poisoning : A common flu-like illness typically characterized by nausea, vomiting and diarrhea , due to something the victim ate or drank that contained noxious bacteria, viruses, parasites, metals or toxins.
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Fungal: Pertaining to a fungus . For example, a fungal skin infection.
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Fungi: Plural of fungus .
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Fungus: A single-celled or multicellular organism. Fungi can be true pathogens (such as histoplasmosis and coccidioidomycosis ) that cause infections in healthy persons or they can be opportunistic pathogens (such as aspergillosis , candidiasis , and cryptococcosis) that cause infections in immunocompromised persons (including cancer patients, transplant recipients, and persons with AIDS ). An example of a common fungus is the yeast organism which causes thrush and diaper rash (diaper dermatitis ). Fungi are also used for the development of antibiotics, antitoxins, and other drugs used to control various human diseases.
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Gastric: Having to do with the stomach.
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Gastrointestinal: Adjective referring collectively to the stomach and small and large intestines.
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Genital: Pertaining to the external and internal organs of reproduction. (Not to be confused with genetic.)
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GI tract: Short for gastrointestinal tract. See: Gastrointestinal tract .
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Gland: 1. A group of cells that secrete a substance for use in the body. For example, the thyroid gland. 2. A group of cells that removes materials from the circulation. For example, a lymph gland.
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Glanders: A bacterial infection that causes a chronic debilitating disease of equids (horses, mules, and donkeys) as well as some members of the cat family and is transmissible to people. The bacterium responsible for glanders is Burkholderia mallei (formerly called Pseudomonas mallei).
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Hantavirus: A group of viruses that cause hemorrhagic fever and pneumonia . The Hantaviruses include the Hantaan virus that causes Korean (and Manchurian) hemorrhagic fever . The Hantavirus Pulmonary Syndrome (HPS) struck the Four Corner area (where the States of Arizona, New Mexico, Colorado, and Utah meet) in 1993 with devastating, frequently fatal consequences. Hantaviruses are transmitted to humans by contact direct or indirect with the saliva and excreta of rodents such as deer mice, field mice, and ground voles. The HPS outbreak in 1993 followed two years in which there was more rain, more foliage, and more deer mice than usual.
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Headache : A pain in the head with the pain being above the eyes or the ears, behind the head (occipital), or in the back of the upper neck. Headache, like chest pain or back ache, has many causes.
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Heart: The muscle that pumps blood received from veins into arteries throughout the body. It is positioned in the chest behind the sternum (breastbone; in front of the trachea, esophagus, and aorta; and above the diaphragm muscle that separates the chest and abdominal cavities. The normal heart is about the size of a closed fist, and weighs about 10.5 ounces. It is cone-shaped, with the point of the cone pointing down to the left. Two-thirds of the heart lies in the left side of the chest with the balance in the right chest.
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Hemorrhagic: Pertaining to bleeding or the abnormal flow of blood.
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HEPA: Acronym that stands for High-Efficiency Particulate Air and for High-Efficiency Particulate Arrestor.
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Hepatitis: Inflammation of the liver from any cause.
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HIV: Acronym for the Human Immunodeficiency Virus , the cause of AIDS (acquired immunodeficiency syndrome). HIV has also been called the human lymphotropic virus type III, the lymphadenopathy-associated virus and the lymphadenopathy virus . No matter what name is applied, it is a retrovirus. (A retrovirus has an RNA genome and a reverse transcriptase enzyme. Using the reverse transcriptase , the virus uses its RNA as a template for making complementary DNA which can integrate into the DNA of the host organism).
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Hospital: It may seem unnecessary to define a "hospital" since everyone knows the nature of a hospital. A hospital began as a charitable institution for the needy, aged, infirm, or young.
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Immune: Protected against infection. The Latin immunis means free, exempt.
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Immunity: The condition of being immune. Immunity can be innate (for example, humans are innately immune to canine distemper) or conferred by a previous infection or immunization.
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Immunization: Vaccination. Immunizations work by stimulating the immune system, the natural disease-fighting system of the body. The healthy immune system is able to recognize invading bacteria and viruses and produce substances (antibodies) to destroy or disable them. Immunizations prepare the immune system to ward off a disease. To immunize against viral diseases, the virus used in the vaccine has been weakened or killed. To immunize against bacterial diseases, it is generally possible to use only a small portion of the dead bacteria to stimulate the formation of antibodies against the whole bacteria. In addition to the initial immunization process, it has been found that the effectiveness of immunizations can be improved by periodic repeat injections or "boosters." Also see Immunizations (in the plural) and Immunization of a specific type (such Immunization, Polio).
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Immunotherapy: Treatment to stimulate or restore the ability of the immune (defense) system to fight infection and disease. Biological therapy is thus any form of treatment that uses the body's natural abilities that constitute the immune system to fight infection and disease or to protect the body from some of the side effects of treatment.
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Incubation period: In medicine, the time from the moment of exposure to an infectious agent until signs and symptoms of the disease appear. For example, the incubation period of chickenpox is 14-16 days.
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Indicate: In medicine, to make a treatment or procedure advisable because of a particular condition or circumstance. For example, certain medications are indicated for the treatment of hypertension during pregnancy while others are contraindicated .
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Infection: The growth of a parasitic organism within the body. (A parasitic organism is one that lives on or in another organism and draws its nourishment therefrom.) A person with an infection has another organism (a "germ") growing within him, drawing its nourishment from the person.
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Inflammation: A basic way in which the body reacts to infection , irritation or other injury, the key feature being redness, warmth, swelling and pain . Inflammation is now recognized as a type of nonspecific immune response .
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Injure: To harm, hurt, or wound. The word injure may be in physical or emotional sense. Treadmill machines may injure anyone who gets on one. Sexual molestation injures children. From the Latin injuria meaning injury.
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Injury: Harm or hurt. The term "injury" may be applied in medicine to damage inflicted upon oneself as in a hamstring injury or by an external agent on as in a cold injury . The injury may be accidental or deliberate, as with a needlestick injury . The term "injury" may be synonymous (depending on the context) with a wound or with trauma .
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Intern: In medicine, a doctor who has completed medical school and is engaged in a year of additional training at a hospital before residency. An intern may, for example, be in pediatrics or medicine (internal medicine). The internship year is often quite rigorous.
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Intervention: The act of intervening, interfering or interceding with the intent of modifying the outcome. In medicine, an intervention is usually undertaken to help treat or cure a condition. For example, early intervention may help children with autism to speak. "Acupuncture as a therapeutic intervention is widely practiced in the United States," according to the National Institutes of Health. From the Latin intervenire, to come between.
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Itching: An uncomfortable sensation in the skin that feels as if something is crawling on the skin or in the skin, and makes the person want to scratch the affected area.
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JAMA: The Journal of the American Medical Association. JAMA began publication in 1883. It now bills itself as "the world's best-read medical journal". However one defines "best-read", JAMA clearly ranks as one of the two leading general medical journals published in the United States. (The other is the New England Journal of Medicine.)
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Joint: A joint is the area where two bones are attached for the purpose of motion of body parts. A joint is usually formed of fibrous connective tissue and cartilage. An articulation or an arthrosis is the same as a joint.
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Kidney: One of a pair of organs located in the right and left side of the abdomen which clear "poisons" from the blood, regulate acid concentration and maintain water balance in the body by excreting urine. The kidneys are part of the urinary tract. The urine then passes through connecting tubes called "ureters" into the bladder. The bladder stores the urine until it is released during urination.

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Laboratory: A place for doing tests and research procedures and preparing chemicals, etc. Although "laboratory" looks very like the Latin "laboratorium" (a place to labor, a work place), the word "laboratory" came from the Latin "elaborare" (to work out, as a problem, and with great pains), as evidenced by the Old English spelling "elaboratory" designating "a place where learned effort was applied to the solution of scientific problems."
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Lassa fever: An acute viral infection found in the tropics, especially in West Africa. Epidemics of Lassa fever have occurred in countries such as Sierra Leone, Congo (formerly Zaire), Liberia and Nigeria.
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Lavage: Washing out. Gastric lavage is washing out the stomach, for example, to remove drugs or poisons.
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Lederberg: See: Lederberg, Joshua
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Leg: In popular usage, the leg extends from the top of the thigh down to the foot. However, in medical terminology, the leg refers to the portion of the lower extremity from the knee to the ankle.
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Lesion: Pronounced "lee-sion" with the emphasis on the "lee," a lesion can be almost any abnormality involving any tissue or organ due to any disease or any injury.
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Lethal: Deadly, fatal, capable of causing death, death-dealing. The word "lethal" comes from the Latin "letum" meaning "death or destruction."
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Lethargy: 1. Abnormal drowsiness, stupor. 2. A state of indifference.
From the Greek lethargia, drowsiness.
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Limb: The arm or leg.
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Liver: An organ in the upper abdomen that aids in digestion and removes waste products and worn-out cells from the blood. The liver is the largest solid organ in the body. The liver weighs about three and a half pounds (1.6 kilograms). It measures about 8 inches (20 cm) horizontally (across) and 6.5 inches (17 cm) vertically (down) and is 4.5 inches (12 cm) thick.

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Liver disease: Liver disease refers to any disorder of the liver. The liver is a large organ in the upper right abdomen that aids in digestion and removes waste products from the blood.
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Low back pain: Pain in the lower back area that can relate to problems with the lumbar spine , the discs between the vertebrae , the ligaments around the spine and discs, the spinal cord and nerves , muscles of the low back, internal organs of the pelvis and abdomen , or the skin covering the lumbar area.
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Low blood pressure : Any blood pressure that is below the normal expected for an individual in a given environment. Low blood pressure is also referred to as hypotension.
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Lungs: The lungs are a pair of breathing organs located with the chest which remove carbon dioxide from and bring oxygen to the blood. There is a right and left lung.
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Lymph: An almost colorless fluid that travels through vessels called lymphatics in the lymphatic system and carries cells that help fight infection and disease.
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Lymph gland: See Lymph node .
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Marrow: The bone marrow .
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Medication: 1. A drug or medicine. 2. The administration of a drug or medicine. (Note that "medication" does not have the dangerous double meaning of "drug.")
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Membrane: A very thin layer of tissue that covers a surface.
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Meningitis: Inflammation of the meninges, usually due to a bacterial infection but sometimes from viral, protozoan, or other causes (in some cases the cause cannot be determined).
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Microscope: An optical instrument that augments the power of the eye to see small objects. The name microscope was coined by Johannes Faber (1574-1629) who in 1628 borrowed from the Greek to combined micro-, small with skopein, to view. Although the first microscopes were simple microscopes, most (if not all) optical microscopes today are compound microscopes.
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Miscarriage: Inadvertent loss of a pregnancy before the fetus is viable. A considerable proportion of pregnancies end in a miscarriage . Also called a spontaneous abortion.
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Monkeypox: A rare zoonotic (animal-borne) viral disease similar to smallpox . The virus responsible for monkeypox is, in fact, related to that responsible for smallpox. Both belong to the orthopox family of viruses.
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Mouth: 1. The upper opening of the digestive tract, beginning with the lips and containing the teeth, gums, and tongue. Foodstuffs are broken down mechanically in the mouth by chewing and saliva is added as a lubricant. Saliva contains amylase, an enzyme that digests starch. 2. Any opening or aperture in the body. The mouth in both senses of the word is also called the os, the Latin word for an opening, or mouth. The o in os is pronounced as in hope. The genitive form of os is oris from which comes the word oral.
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Mucous: Pertaining to mucus, a thick fluid produced by the lining of some tissues of the body.
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Muscle: Muscle is the tissue of the body which primarily functions as a source of power. There are three types of muscle in the body. Muscle which is responsible for moving extremities and external areas of the body is called "skeletal muscle." Heart muscle is called "cardiac muscle." Muscle that is in the walls of arteries and bowel is called "smooth muscle."
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Muscular: Having to do with the muscles. Also, endowed with above average muscle development. Muscular system refers to all of the muscles of the body collectively.
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Mycotoxin: A toxin produced by a fungus . A mycotoxin may be formed when grains or some other products become moldy. From myco-, fungal + -toxin = a fungal toxin.
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Nasal: Having to do with the nose. Nasal drops are intended for the nose, not (for example) the eyes. The word "nasal" came from the Latin "nasus" meaning the nose or snout.
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Nausea: Nausea, is the urge to vomit. It can be brought by many causes including, systemic illnesses, such as influenza , medications, pain, and inner ear disease. When nausea and/or vomiting are persistent, or when they are accompanied by other severe symptoms such as abdominal pain , jaundice , fever, or bleeding, a physician should be consulted.
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Neck: The part of the body joining the head to the shoulders. Also, any narrow or constricted part of a bone or organ that joins its parts as, for example, the neck of the femur bone.
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Nose: The external midline projection from the face.
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Onset: In medicine, the first appearance of the signs or symptoms of an illness as, for example, the onset of rheumatoid arthritis . There is always an onset to a disease but never to the return to good health. The default setting is good health.
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Operation: Although there are many meanings to the word "operation", in medicine it refers to a surgical procedure.
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Organ: A relatively independent part of the body that carries out one or more special functions. The organs of the human body include the eye , ear , heart , lungs , and liver .
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Organic: 1. A chemical compound that contains carbon.
2. Related to an organ.
3. Grown or prepared without the use of chemicals or pesticides, as in organic food.
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Oxygenation: The addition of oxygen to any system, including the human body. Oxygenation may also refer to the process of treating a patient with oxygen, or of combining a medication or other substance with oxygen.
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Pain: An unpleasant sensation that can range from mild, localized discomfort to agony. Pain has both physical and emotional components. The physical part of pain results from nerve stimulation. Pain may be contained to a discrete area, as in an injury, or it can be more diffuse, as in disorders like fibromyalgia . Pain is mediated by specific nerve fibers that carry the pain impulses to the brain where their conscious appreciation may be modified by many factors.
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Paralysis: Loss of voluntary movement (motor function). Paralysis that affects only one muscle or limb is partial paralysis, also known as palsy; paralysis of all muscles is total paralysis, as may occur in cases of botulism .
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Penicillin : The most famous of all antibiotics, named for the fungal mold Penicillium notatum from which it is derived. Penicillin acts by destroying the cell wall of bacteria .
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Pestis: The plague. An infectious disease due to a bacteria called Yersinia pestis .
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Pharmacy: A location where prescription drugs are sold. A pharmacy is, by law, constantly supervised by a licensed pharmacist.
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Pimple: A small papule or pustule . Pimples are sebaceous glands (oil glands) that are infected with bacteria , become inflamed, and fill with pus . Pimples are due to overactivity of the sebaceous glands located at the base of the hair follicles, especially on the face, back, chest, and shoulders. They are a visible and palpable hallmark of acne .
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Plague: The plague is an infectious disease due to a bacteria called Yersinia pestis .
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Pneumonia: Inflammation of one or both lungs with consolidation. Pneumonia is frequently but not always due to infection. The infection may be bacterial, viral, fungal or parasitic. Symptoms may include fever, chills, cough with sputum production, chest pain, and shortness of breath.
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Pneumonic plague: Infection of the lungs by Yersina pestis , the bacterial agent that causes the plague , a disease of animals (rodents and their fleas) and humans.
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Poison: Any substance that can cause severe distress or death if ingested, breathed in, or absorbed through the skin. Many substances that normally cause no problems, including water and most vitamins , can be poisonous if taken in too large of a quantity. Poison treatment depends on the substance: if there are treatment instructions on the substance's container and you are sure it contained no other item, follow those directions immediately. Always contact your nearest Poison Control Center if you are concerned about possible poison ingestion.
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Poisoning: Taking a substance that is injurious to health or can cause death. Poisoning is still a major hazard to children, despite child-resistant (and sometimes adult-resistant) packaging and dose-limits per container.
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Potassium: The major positive ion (cation) found inside of cells. The chemical notation for potassium is K⁺.
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Pregnant: The state of carrying a developing fetus within the body.
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Primary: First or foremost in time or development. The primary teeth (the baby teeth) are those that come first. Primary may also refer to symptoms or a disease to which others are secondary.
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Prophylaxis: A measure taken for the prevention of a disease or condition.
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Protein: A large molecule composed of one or more chains of amino acids in a specific order determined by the base sequence of nucleotides in the DNA coding for the protein.
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Proteins: Large molecules composed of one or more chains of amino acids in a specific order determined by the base sequence of nucleotides in the DNA coding for the protein.
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Public health: The approach to medicine that is concerned with the health of the community as a whole. Public health is community health. It has been said that: "Health care is vital to all of us some of the time, but public health is vital to all of us all of the time."
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Q fever: An acute febrile illness due to Coxiella burnetii (C. burnetii), a species of bacteria. Q fever is a zoonotic disease (contracted from animals). Aside from sudden onset of fever , there is headache, malaise, and pneumonia but no rash .
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Rash : Breaking out (eruption) of the skin. Medically, a rash is referred to as an exanthem.
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Recur: To occur again. To return. Any symptom (such as fatigue), any sign (such as a heart murmur), or any disease can recur.
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Relapse: The return of signs and symptoms of a disease after a patient has enjoyed a remission . For example, after treatment a patient with cancer of the colon went into remission with no sign or symptom of the tumor, remained in remission for 4 years, but then suffered a relapse and had to be treated once again for colon cancer.
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rep: 1) Roentgen equivalent physical, a unit of absorbed radiation approximately equivalent to one roentgen. 2) An abbreviation for repetition when referring to an exercise maneuver. 3) An abbreviation for representative of sales for a pharmaceutical or health products company.
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Respiratory: Having to do with respiration, the exchange of oxygen and carbon dioxide. From the Latin re- (again) + spirare (to breathe) = to breathe again.
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Respiratory failure: Inability of the lungs to perform their basic task of gas exchange , the transfer of oxygen from inhaled air into the blood and the transfer of carbon dioxide from the blood into exhaled air. The basis of respiratory failure may be failure of the exchange of oxygen and carbon dioxide within the tiny air sacs (alveoli) in the lungs; failure of the muscles required to expand the lungs; or failure of the brain centers controlling respiration.
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Ricin: A potent protein toxin made from the waste left over from processing castor beans. The castor plant, which is called Ricinus communis, is found throughout the world. Ricin is fairly easy to extract. Worldwide a million tons of castor beans are processed annually in the production of castor oil. The waste mash from this process is 5% ricin by weight.
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Rift Valley fever: A viral disease that is acute, causes fever in domestic animals (such as cattle, buffalo, sheep, goats, and camels) and humans, and is associated with mosquito-borne epidemics during years of heavy rainfall. Rift Valley fever is more deadly than West Nile virus.
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RNA: Short for ribonucleic acid, a nucleic acid molecule similar to DNA but containing ribose rather than deoxyribose. RNA is formed upon a DNA template. There are several classes of RNA molecules.
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Saline: Relating to salt. As an adjective, "saline" means "salty, containing salt." As a noun "saline" is a salt solution, often adjusted to the normal salinity of the human body.
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Salmonella: A group of bacteria that cause typhoid fever and a number of other illnesses, including food poisoning , gastroenteritis and enteric fever from contaminated food products.
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Salmonellosis: Infection with bacteria belonging to the genus Salmonella. Salmonellosis is a common cause of food poisoning as, for example, from raw eggs .
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Sedative: A drug that calms a patient down, easing agitation and permitting sleep . Sedatives generally work by modulating signals within the central nervous system. These sedatives can dangerously depress important signals needed to maintain heart and lung function if they are misused or accidentally combined, as in the case of combining prescription sedatives with alcohol. Most sedatives also have addictive potential. For these reasons, sedatives should be used under supervision, and only as needed.
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Sensitivity: 1. In psychology, the quality of being sensitive. As, for example, sensitivity training, training in small groups to develop a sensitive awareness and understanding of oneself and of ones relationships with others. 2. In disease epidemiology, the ability of a system to detect epidemics and other changes in disease occurrence. 3. In screening for a disease, the proportion of persons with the disease who are correctly identified by a screening test. 4. In the definition of a disease, the proportion of persons with the disease who are correctly identified by defined criteria.
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Septicemia: Systemic (bodywide) illness with toxicity due to invasion of the bloodstream by virulent bacteria coming from a local seat of infection. The symptoms of chills, fever and exhaustion are caused by the bacteria and substances they produce. The disorder is treated with massive doses of antibiotics. Also known as blood poisoning.
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Serum: The clear liquid that can be separated from clotted blood. Serum differs from plasma, the liquid portion of normal unclotted blood containing the red and white cells and platelets. It is the clot that makes the difference between serum and plasma.
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Shock: In medicine, shock is a critical condition brought on by a sudden drop in blood flow through the body. There is failure of the circulatory system to maintain adequate blood flow. This sharply curtails the delivery of oxygen and nutrients to vital organs. It also compromises the kidney and so curtails the removal of wastes from the body. Shock can be due to a number of different mechanisms including not enough blood volume (hypovolemic shock) and not enough output of blood by the heart (cardiogenic shock). The signs and symptoms of shock include low blood pressure (hypotension), overbreathing (hyperventilation), a weak rapid pulse, cold clammy grayish-bluish (cyanotic) skin, decreased urine flow (oliguria), and mental changes (a sense of great anxiety and foreboding, confusion and, sometimes, combativeness).
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Sign: Any objective evidence of disease. Gross blood in the stool is a sign of disease. It can be recognized by the patient, doctor, nurse, or others. In contrast, a symptom is, by its nature, subjective. Abdominal pain is a symptom. It is something only the patient can know.
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Skin: The skin is the body's outer covering. It protects us against heat and light, injury, and infection. It regulates body temperature and stores water, fat, and vitamin D. Weighing about 6 pounds, the skin is the body's largest organ. It is made up of two main layers; the outer epidermis and the inner dermis.

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Skin color: The color of skin which is complexly determined. Skin color depends on many factors including reddening caused by inflammation , the hemoglobin level in the blood, and the darkening caused by increased deposition of the pigment melanin . Melanin itself is a polymer that comes in two types -- a red-yellow form known as pheomelanin and a black-brown form known as eumelanin.
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Smallpox: Also known as variola, a highly contagious and frequently fatal viral disease characterized by a biphasic fever and a distinctive skin rash that left pock marks in its wake. Because of its high case-fatality rates and transmissibility, smallpox now represents a serious bioterrorist threat. The disease is caused by the variola virus. The incubation period is about 12 days (range: 7 to 17 days) following exposure. Initial symptoms include high fever, fatigue , and head and back aches. A characteristic rash, most prominent on the face, arms, and legs, follows in 2-3 days. The rash starts with flat red lesions that evolve at the same rate. Lesions become pus-filled and begin to crust early in the second week. Scabs develop and then separate and fall off after about 3-4 weeks.
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Smallpox vaccine: A vaccine containing a live virus called vaccinia used to prevent smallpox. The vaccine does not contain the variola virus that causes smallpox. Through the use of the vaccine, smallpox was eliminated from the world in 1977. Routine vaccination against smallpox ended in 1972 The level of immunity among persons who were vaccinated before 1972 is uncertain. In people exposed to smallpox who are not immune to the disease, the vaccine can lessen the severity of or even prevent the illness if given within 4 days of exposure.
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Sodium: The major positive ion (cation) in fluid outside of cells. The chemical notation for sodium is Na⁺. When combined with chloride, the resulting substance is table salt.
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Sore: 1. (adjective) A popular term for painful. I have sore fingers from typing dictionary terms. She has a sore throat . 2. (noun) A nondescript term for nearly any lesion of the skin or mucous membranes. He has a number of sores in his mouth.

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Sore throat : Pain in the throat. Sore throat may be caused by many different causes, including inflammation of the larynx, pharynx, or tonsils.
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Spinal tap: Also known as a lumbar puncture or "LP", a spinal tap is a procedure whereby spinal fluid is removed from the spinal canal for the purpose of diagnostic testing. It is particularly helpful in the diagnosis of inflammatory diseases of the central nervous system, especially infections, such as meningitis. It can also provide clues to the diagnosis of stroke , spinal cord tumor and cancer in the central nervous system.
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Spleen: An organ located in the upper left part of the abdomen near the stomach . The spleen produces lymphocytes ; it is the largest lymphatic organ in the body. The spleen also filters the blood, serves as a major reservoir for blood and destroys blood cells that are aged.
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Sputum: The mucus and other matter brought up from the lungs , bronchi , and trachea that one may cough up and spit out or swallow. The word "sputum" is borrowed directly from the Latin "to spit." Called also expectoration.
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Stage: As regards cancer , the extent of a cancer, especially whether the disease has spread from the original site to other parts of the body. See also: Staging .
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Stomach: 1. The sac-shaped digestive organ that is located in the upper abdomen, under the ribs. The upper part of the stomach connects to the esophagus, and the lower part leads into the small intestine.
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Stool: The solid matter discharged in a bowel movement.
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Strain: 1. An injury to a tendon or muscle resulting from overuse or trauma. 2. A hereditary tendency that originated from a common ancestor. 3. To exert maximum effort. 4. To filter.
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Substance: 1. Material with particular features, as a pressor substance .
2. The material that makes up an organ or structure. Also known in medicine as the substantia.
3. A psychoactive drug as, for example, in substance abuse .
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Surgeon: A physician who treats disease, injury, or deformity by operative or manual methods. A medical doctor specialized in the removal of organs, masses and tumors and in doing other procedures using a knife (scalpel). The definition of a "surgeon" has begun to blur in recent years as surgeons have begun to minimize the cutting, employ new technologies that are "minimally invasive," use scopes, etc.
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Surgeon General: In the United States, the chief medical officer of the U.S. Public Health Service (USPS), the agency responsible for the public health of the American people. The Public Health Service ( PHS ) administers a number of critically important health agencies including the Food and Drug Administration ( FDA ), the Centers for Disease Control ( CDC ), and the National Institutes of Health ( NIH ).
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Sweating: The act of secreting fluid from the skin by the sweat (sudoriferous) glands. These are small tubular glands situated within and under the skin (in the subcutaneous tissue). They discharge by tiny openings in the surface of the skin.
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Symptom: Any subjective evidence of disease. Anxiety, lower back pain , and fatigue are all symptoms. They are sensations only the patient can perceive. In contrast, a sign is objective evidence of disease. A bloody nose is a sign. It is evident to the patient, doctor, nurse and other observers.
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Synthesis: Putting together different entities to make a whole which is new and different. In biochemistry , synthesis refers specifically to the process of building compounds from more elementary substances by means of one or more chemical reactions.
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Syphilis: A sexually transmitted disease caused by Treponema pallidum, a microscopic organism called a spirochete. This worm-like, spiral-shaped organism infects people by burrowing into the moist mucous membranes of the mouth or genitals. From there, the spirochete produces a non-painful ulcer known as a chancre. There are three stages of syphilis:
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Systemic: Affecting the entire body. A systemic disease such as diabetes can affect the whole body. Systemic chemotherapy employs drugs that travel through the bloodstream and reach and affect cells all over the body.
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Tetracycline: A family of broad-spectrum antibiotics effective against a remarkably wide variety of organisms. Bacteria susceptible to teracycline include H. flu (Hemophilus influenzae), strep (Streptococcus pneumoniae), Mycoplasma pneumoniae, Chlamydia psittaci, Chlamydia trachomatis , and Neisseria gonorrhoeae (the cause of gonorrhea ). Tetracycline is also used to treat nongonococcal urethritis (due to Ureaplasma), Rocky mountain spotted fever , typhus , chancroid , cholera , brucellosis , anthrax , and syphilis . It is used in combination with other medications to treat Helicobacter pylori , the bacteria associated with ulcers of the stomach and duodenum .
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Therapy: The treatment of disease .
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Thigh: The thigh extends from the hip to the knee. The thigh has only one bone, the femur which is the largest bone in the human body.
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Throat: The throat is the anterior (front) portion of the neck beginning at the back of the mouth , consisting anatomically of the pharynx and larynx . The throat contains the trachea and a portion of the esophagus .
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Tired: A feeling of a lessened capacity for work and reduced efficiency of accomplishment, usually accompanied by a sense of weariness and fatigue.
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Tiredness: See: Tired .
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Tissue: A tissue in medicine is not like a piece of tissue paper. It is a broad term that is applied to any group of cells that perform specific functions. A tissue in medicine need not form a layer. Thus,

• The bone marrow is a tissue;
• Connective tissue consists of cells that make up fibers in the framework supporting other body tissues; and
• Lymphoid tissue is the part of the body's immune system that helps protect it from bacteria and other foreign entities.

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Topical: Pertaining to a particular surface area. A topical agent is applied to a certain area of the skin and is intended to affect only the area to which it is applied. Whether its effects are indeed limited to that area depends upon whether the agent stays where it is put or is absorbed into the blood stream.
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Toxic shock: See Toxic shock syndrome.
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Toxicity: The degree to which a substance can harm humans or animals.
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Toxicology: The study of the nature, effects and detection of poisons and the treatment of poisoning.
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Toxin: One of a number of poisons produced by certain plants, animals, and bacteria.
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Tuberculosis : A highly contagious infection caused by the bacterium called Mycobacterium tuberculosis. Abbreviated TB. Tubercles (tiny lumps) are a characteristic finding in TB. Diagnosis may be made by skin test, which if positive should will be followed by a chest X-ray to determine the status (active or dormant) of the infection. Tuberculosis is more common in people with immune system problems, such as AIDS, than in the general population. Treatment of active tuberculosis is mandatory by law in the US, and should be available at no cost to the patient through the public health system. It involves a course of antibiotics and vitamins that lasts about six months. It is important to finish the entire treatment, both to prevent reoccurrence and to prevent the development of antibiotic-resistant tuberculosis. Most patients with tuberculosis do not need to be quarantined, but it is sometimes necessary.
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Tularemia: A bacterial disease caused by infection with a bacterium called Francisella tularensis that usually occurs in wild and domestic animals, most often rabbits, and can be transmitted to humans by contact with animal tissues or ticks and fleas. Also called rabbit fever and deerfly fever.
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Vaccination: Injection of a killed microbe in order to stimulate the immune system against the microbe, thereby preventing disease. Vaccinations, or immunizations , work by stimulating the immune system, the natural disease-fighting system of the body. The healthy immune system is able to recognize invading bacteria and viruses and produce substances (antibodies) to destroy or disable them. Immunizations prepare the immune system to ward off a disease. To immunize against viral diseases, the virus used in the vaccine has been weakened or killed. To only immunize against bacterial diseases, it is generally possible to use a small portion of the dead bacteria to stimulate the formation of antibodies against the whole bacteria. In addition to the initial immunization process, it has been found that the effectiveness of immunizations can be improved by periodic repeat injections or "boosters." Also see Vaccines (in the plural) and Vaccine of a specific type (such Vaccine, Polio).
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Vaccines: Microbial preparations of killed or modified microorganisms that can stimulate an immune response in the body to prevent future infection with similar microorganisms. These preparations are usually delivered by injection.
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Valley fever: A disease also called coccidioidomycosis (CM) due to a fungus called Coccidioides immitis. About 40% of people infected with this fungus develop symptoms. Most often they have an influenza-like illness with fever, cough, headaches , rash , and myalgias (muscle pains). Of those people with symptoms, 8% have severe lung disease requiring hospitalization and 7% develop disseminated infection (throughout the body).
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Variola: Smallpox, a highly contagious and frequently fatal viral disease characterized by a biphasic (double-humped) fever and a distinctive skin rash that (if the patient survived) left pock marks in its wake. The English physician Edward Jenner (1749-1823) exploited the fact that cowpox created immunity to smallpox and successfully developed an attenuated (weakened) virus vaccine for smallpox. Thanks to vaccination, smallpox has been eradicated. It was so named because the pocks were small and the disease was seen as less than the "great pox" (syphilis).
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Vector: In medicine, a vector is a carrier. The best way to understand a vector is to recall its origin as a word. Vector is the Latin word for a "bearer."
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Venomous: 1. Full of venom . 2. Having venom, like some snakes and insects. 3. By extension, noxious, as a venomous tongue.
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Ventilator: A ventilator is a machine which mechanically assists patients in the exchange of oxygen and carbon dioxide (sometimes referred to as artificial respiration).
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Vibramycin: Brand name for doxycycline .
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Vibrio: A group of bacteria that includes Vibrio cholerae, the agent of cholera , (a devastating and sometimes lethal disease with profuse watery diarrhea ) and Vibrio comma (which is shaped like a comma). Vibrio move about actively . The word "vibrio" in Latin means "to quiver."
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Vibrio cholerae: One of the Vibrio bacteria, V. cholerae (as the name implies) is the agent of cholera , a devastating and sometimes lethal disease with profuse watery diarrhea .
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Viral: Of or pertaining to a virus. For example, "My daughter has a viral rash ."
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Viral hemorrhagic fever: A syndrome caused by infection with one of a number of viruses that can cause increased permeability of the blood vessels resulting in bleeding into the skin, internally, or from the mouth or other orifices. The bleeding is usually not life-threatening. Other signs and symptoms of viral hemorrhagic fever (VHF) may also include high fever, weakness, dizziness, and myalgia . In severe cases, there may be shock, coma, delirium , seizures , and death.
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Virulent: Extremely noxious, damaging, deleterious, disease-causing ( pathogenic ). Marked by a rapid, severe, and malignant course. Poisonous, venomous.
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Virus: A microorganism smaller than a bacteria, which cannot grow or reproduce apart from a living cell. A virus invades living cells and uses their chemical machinery to keep itself alive and to replicate itself. It may reproduce with fidelity or with errors (mutations)-this ability to mutate is responsible for the ability of some viruses to change slightly in each infected person, making treatment more difficult.
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Viruses: Small living particles that can infect cells and change how the cells function. Infection with a virus can cause a person to develop symptoms. The disease and symptoms that are caused depend on the type of virus and the type of cells that are infected.
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Vomit: Matter from the stomach that has come up into and may be ejected beyond the mouth, due to the act of vomiting.
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Weight loss: Weight loss is a decrease in body weight resulting from either voluntary ( diet , exercise ) or involuntary (illness) circumstances. Most instances of weight loss arise due to the loss of body fat, but in cases of extreme or severe weight loss, protein and other substances in the body can also be depleted. Examples of involuntary weight loss include the weight loss associated with cancer , malabsorption (such as from chronic diarrheal illnesses ), and chronic inflammation (such as with rheumatoid arthritis ).
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Wheezing: A whistling noise in the chest during breathing when the airways are narrowed or compressed.
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World Health Organization: An agency of the United Nations established in 1948 to further international cooperation in improving health conditions. Although the World Health Organization inherited specific tasks relating to epidemic control, quarantine measures, and drug standardization from the Health Organization of the League of Nations (that was set up in 1923) and from the International Office of Public Health at Paris (established in 1909), the World Health Organization was given a broad mandate under its constitution to promote the attainment of "the highest possible level of health" by all people. WHO defines health positively as "a state of complete physical, mental, and social well-being and not merely the absence of disease or infirmity."
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X-ray: 1. High-energy radiation with waves shorter than those of visible light. X-rays possess the properties of penetrating most substances (to varying extents), of acting on a photographic film or plate (permitting radiography), and of causing a fluorescent screen to give off light (permitting fluoroscopy). In low doses X-rays are used for making images that help to diagnose disease, and in high doses to treat cancer . Formerly called a Roentgen ray. 2. An image obtained by means of X-rays.
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Yellow fever: An acute systemic (bodywide) illness caused by a virus called a Flavivirus . In severe cases, the viral infection causes a high fever, bleeding into the skin, and necrosis (death) of cells in the kidney and liver. The damage done to the liver from the virus results in severe jaundice which yellows the skin. Hence, the "yellow" in "yellow fever."
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Yersinia: A group of bacteria that appear rod-like under the microscope and include Yersinia pestis (the cause of the bubonic and pneumonic plague ), Yersinia entercolitica (the cause of a disease called yersinosis ), and Yersinia pseudotuberculosis (which causes a condition called mesenteric adenitis, particularly in immunocompromised patients). Both Y. entercolitica and Y. pseudotuberculosis have also been implicated in a viral form of arthritis . Infection with Yersinia bacteria can be treated with antibiotics.
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Yersinia pestis: The bacteria that causes the bubonic plague which in the year 541 (as the Black Death ) and later in the Middle Ages decimated Europe. The effects of the plague are described in the nursery rhyme "We all fall down."
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