Salmonellosis, any of a group of infectious diseases caused by intestinal bacteria of the genus Salmonella, including typhoid fever, paratyphoid fever, blood poisoning, and food poisoning (gas...

Bretonneau, Pierre, 1778–1862, French physician. He performed (1825) the first successful tracheotomy for laryngeal diphtheria, wrote a treatise (1826) distinguishing between scarlet fever and...

Housefly, common name of the fly Musca domestica, found in most parts of the world. The housefly, a scavenger, does not bite living animals but is dangerous because it carries bacteria and pro...

Hemorrhage, escape of blood from the circulation (arteries, veins, capillaries) to the internal or external tissues. The term is usually applied to a loss of blood that is copious enough to th...

Chloramphenicol, antibiotic effective against a wide range of gram-negative and gram-positive bacteria (see Gram's stain). It was originally isolated from a species of Streptomyces bacteria. C...

Baldness, thinning or loss of hair as a result of illness, functional disorder, or hereditary disposition; also known as alopecia. Male pattern baldness, a genetic trait, is the most common ca...

Diarrhea, frequent discharge of watery feces from the intestines, sometimes containing blood and mucus. It can be caused by excessive indulgence in alcohol or other liquids or foods that prove...

Parasite, plant or animal that at some stage of its existence obtains its nourishment from another living organism called the host. Parasites may or may not harm the host, but they never benef...

Vaccination, means of producing immunity against pathogens, such as viruses and bacteria, by the introduction of live, killed, or altered antigens that stimulate the body to produce antibodies...

Douglas, Stephen Arnold, 1813–61, American statesman, b. Brandon, Vt. He was admitted to the bar at Jacksonville, Ill., in 1834. After holding various state and local offices he became a U.S. ...