A system of vessels and organs that picks up excess fluid, proteins, lipids, and other substances from the tissues; filters out pathogen and other waste products; and returns the cleansed fluid to the general circulation.
An infection spread by the blood or lympatic system to large portions of the body.
Atype of white blood cell that engulfs foreign organisms and infected, damaged, or aged cells; particularly prevalent during the inflammatory response.
A large phagocytic (cell-eating) cell that devours foreign particles.
Natural killer cell
A type of white blood cell that directly destroys virus-infected cells and cancer cells.
A white blood cells specialized to activate T and B cells
A white blood cell continuously made in lymphoid tissues as weel as in bone marrow.
A lymphocyte that arises in bone marrow and matures in the thymus(thus its name)
A lymphocyte that matures in the bone marrow and produces antibodies.
Helper T cell
A lymphocyte that helps activate other T cells and may help B cells produce antibodies.
Killer T cell
A lymphocyte that kills body cells that have been invaded by foreign organisms.
Suppressor T cell
A lymphoctye that inhibits the growth of other lymphocyte.
A specialized protein, by white blood cells, that can recognize and neutralize specific microbes.
Memory T and B cells
Lymphocytes generated during an initial infection that circulate in the body for years, "remembering" the specific antigens that caused the infection and quickly destroying them if they appear agina.
A disease in which the immune system attacks the person's own body.
A marker on the surface of a foreign substance that immune system cells recognize as nonself and that triggers the immune response
A chemical responsible for the dilation and increased permeability of blood vessels in allergic reactions.
Mechanisms that defend the body against infection; specific defenses against specifuc pathogens.
The period of when bacteria or viruses are actively multiplying inside the body's cells; usually a period without symptoms of illness.
The stage of an infection following incubation, during which initial symptoms begin to appear but the host does not feel ill; a highly contagioud period.
A preparation of killed or weakened microorganisms, inactivated toxins or components of microorganisms that is administered to stimulate an immune response; a vaccine protects against the future infetion by the pathogen.
A disorder caused by the body's exaggerated response to foreign chemcials and proteins; also called hypersensitivty.
A substance that triggers an allergic reaction.
A severe systemic hypersensitive reaction to an allergen characterized by difficulty breathing, low blood pressure heart arrhythmia, seizure, and sometimes death.
A microscopic single-celled organism; about 100 bacterial species can cause disease in humans
Inflammation of the lungs, typically caused by infection or exposure to chemical toxins or irritants
Infection of the membranes covering the brain and spinal cord(meninges)
Any of a genus of spherical bacteria; can cause skin infections, rheumatic fever pneumonia and toxic shock syndrome.
Toxic Shock syndrome
Sudden onset of fever, aches, vomiting, and peeling rash folled in some cases by shock and inflammation of multiple organs
A chronic bacterial infection that usually affects the lungs.
Persisten and relatively widespread in a given population
A very small infectious agent composed of necleic acid surrounded by a protein coat; lacks and independent metabolism and reproduces only within a host cell.
A disease that can be transmitted from one person to another; most are vital diseases such as the common cold or flu
Infection of the respiratory tract by the influenza virus, which is highly infectious and adaptable; the form changes so easily that every year new strains arise, making treatment difficult, commly known as the flu.
The occurence in a particular community or region of more than the expected number of cases of a particular disease
A disease epidemic that is unusually severe or widespread; often used to refer to worldwide epidemics affecting a large proportion of the population.
A family of viruses responsible for cold sores, monoucleosis, and chicken pox; frequently causes latent infections.
Inflammation of the liver, which can be caused by infection, drugs, or toxins.
A single-celled or multicelled organism that absorbs food from living or dead organic matter
A microscopic single-celled organism that often produces recurrent, cyclical attacks of disease.
A pathogen that causes intestinal and other infections
Proteinaceous infectious particles thought to be responsible for a class of neurodegenerative diseases
Sexually Transmitted Disease
A disease that can be transmitted by sexual contact
Accquired immunodeficiency syndrome
A generally fatal, incurable, sexually transmitted viral disease
Human immunodeficiency virus
The virus that causes HIV infection and AIDS
A chronic, progressive viral infection that damages the immune system.
CD4 T cell
A type of white blood cell that helps coordinate the activity of the immune system; the primary target for HIV infection. A decrease in the number of these cells correlates with the risk and severity of HIV-related illness.
A hereditarty blood disease in which blood fails to clot and abnormal bleeding occurs, requiring transfussions of blood products with a specific factor to aid coagulation.
HIV RNA assay
A test used to determin the amount of HIV in the blood.
HIV antibody test
A blood test to determine whether a person has been infected by HIV; becomes positive within weeks or months of exposure.
EUSA(Enzyme-linked immunosorbent assay)
A blood test that detects the presence of antibodies to HIV
A blood test that detects the presence of HIV antibodies; a more accurate and more expensive test used to confirm positive results from an ELISA test.
A diagnosis resulting from the presence of HIV in the bloodstream; also referred to as seropositive
The appearance of antibodies to HIV in the blood of an infected person; usuallt occurs 1-6 months after infections.
An STD transmitted by the pathogenic bacterium
A sexually transmitted bacterial infection that usually affects mucous membranes
Pelvic inflammatory disease
An infection that progresses from the vagine and cervix to the uterus, oviducts, and pelvic cavity
The pathogen that causes human wartss including genital warts.
A sexually transmitted viral infection characterized by growths on the genitals
A sexually transmitted infection caused by the herpes simplex virus.
A sexually transmitted bacterial infection caused by the spirochete Treponema pallidum.
The sore produced by syphilis in its earliest stage.