Columbia Encyclopedia

(Encyclopedia) hepatitis hĕpˌətīˈtĭs [key], inflammation of the liver. There are many types of hepatitis. Causes include viruses, toxic chemicals, alcohol consumption, parasites and bacteria, and certain drugs...

(Encyclopedia) tick, small, parasitic arachnid of the order Ixodida, closely related to the mites. Ticks, which are larger than the often microscopic mites, are all parasitic in at least one developmental stage; mos...

(Encyclopedia) anemia ənēˈmēə [key], condition in which the concentration of hemoglobin in the circulating blood is below normal. Such a condition is caused by a deficient number of erythrocytes (red blood cell...

(Encyclopedia) lumpy jaw, infectious disease of cattle and swine caused by the bacterium Actinomyces bovis. It is characterized by an infection of the bone of the head, particularly the mandible and the maxilla, wit...

(Encyclopedia) Duchenne, Guillaume Benjamin Amand gēyōmˈ bäNzhämăNˈ ämäNˈ düshĕnˈ [key], 1806–75, French physician. He is noted for researches on diseases of the muscular and nervous systems and for h...

(Encyclopedia) myasthenia gravis mīəsthēˈnēə gräˈvĭs [key], chronic disorder of the muscles characterized by weakness and a tendency to tire easily. It is caused by an autoimmune attack on the acetylcholine...

(Encyclopedia) MERS or Middle East respiratory syndrome, relatively rare viral disease caused by MERS-CoV, a coronavirus. Although some infected persons have no or only coldlike symptoms, in most known cases of MERS...

(Encyclopedia) Mastigophora măsˌtĭgŏfˈərə [key], phylum of unicellular heterotrophic protozoans of the kingdom Protista. Most of the approximately 1,500 species of Mastigophora are propelled by one or more fl...

(Encyclopedia) pinworm, roundworm, Enterobius vermicularis, worldwide in distribution and the most common source of worm infestation of humans in the United States. Children are more commonly infested than adults. A...

(Encyclopedia) heartburn, burning sensation beneath the breastbone, also called pyrosis. Heartburn does not indicate heart malfunction but results from nervous tension or overindulgence in food or drink. The sensati...