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A disease caused by the presence of the sporozoan Plasmodium in human or other vertebrate red blood cells, usually transmitted to humans by the bite of an infected female mosquito of the genus Anopheles that previously sucked the blood from a person with m.. Human infection begins with the exoerythrocytic cycle in liver parenchyma cells, followed by a series of erythrocytic schizogenous cycles repeated at regular intervals; production of gametocytes in other red cells provides future gametes for another mosquito infection; characterized by episodic severe chills and high fever, prostration, occasionally fatal termination. See tropical diseases, under disease. SEE ALSO: Plasmodium. SYN: jungle fever, marsh fever, paludal fever. [It. malo (fem. mala), bad, + aria, air, referring to the old theory of the miasmatic origin of the disease]
- acute m. a form of m. that may be intermittent or remittent, consisting of a chill accompanied and followed by fever with its attendant general symptoms and terminating in a sweating stage; the paroxysms, caused by release of merozoites from infected cells, typically recur every 48 hours in tertian (vivax or ovale) m., every 72 hours in quartan (malariae) m., and at indefinite but frequent intervals, usually about 48 hours, in malignant tertian (falciparum) m., but in many cases the periodicity is not well established.
- airport m. m. inadvertently imported by transport of an infected anopheline mosquito on an airplane.
- algid m. a form of falciparum m. chiefly involving the gut and other abdominal viscera; gastric algid m. is characterized by persistent vomiting; dysenteric algid m. is characterized by bloody diarrheic stools in which enormous numbers of infected red blood cells are found.
- bilious remittent m. a form of falciparum m. characterized by bilious vomiting, bilious diarrhea, etc.
- cerebral m. a form of falciparum m. characterized by cerebral involvement, with extreme hyperthermia and headache, and a case fatality rate of about 50%.
- chronic m. m. that develops after frequently repeated attacks of one of the acute forms, usually falciparum m.; it is characterized by profound anemia, enlargement of the spleen, emaciation, mental depression, sallow complexion, edema of ankles, feeble digestion, and muscular weakness. SYN: limnemia, malarial cachexia.
- m. comatosa falciparum m. complicated by coma.
- falciparum m. m. caused by Plasmodium falciparum and characterized by malarial paroxysms of severe form that typically occur every 48 hours with acute cerebral, renal, or gastrointestinal manifestations in severe cases, chiefly caused by the large number of red blood cells affected and the tendency for infected red cells to become sticky and clump, thus blocking capillaries. SEE ALSO: malarial knobs, under knob. SYN: aestivoautumnal fever, falciparum fever, malignant tertian fever, malignant tertian m., pernicious m..
- induced m. m. acquired by artificial means, e.g., via blood transfusion, common syringes, or malariotherapy.
- intermittent m. a malarial fever, usually of the tertian or quartan type, in which there is complete apyrexia, with absence of the other symptoms, in the intervals between the paroxysms.
- malariae m. a malarial fever with paroxysms that typically recur every 72 hours or every fourth day, reckoning the day of the paroxysm as the first; due to the schizogony and release of merozoites from infected cells, with invasion of new red blood corpuscles by Plasmodium malariae. SYN: quartan fever, quartan m..
- monkey m. SYN: simian m..
- nonan m. a malarial fever with paroxysms that occur every ninth day, i.e., every eighth day following the preceding paroxysm, the day of each paroxysm being included in the computation.
- ovale m., ovale tertian m. m. caused by Plasmodium ovale.
- pernicious m. SYN: falciparum m..
- quartan m. SYN: malariae m..
- quotidian m. m. in which the paroxysms occur daily; usually a double tertian m., in which there is an infection by two distinct groups of Plasmodium vivax parasites sporulating alternately every 48 hours, but also may be an infection by the pernicious form of malarial parasite, P. falciparum, combined with P. vivax, or infection by two distinct P. falciparum generations, which mature on different days; also may develop from infection with P. knowlesi. SYN: quotidian fever.
- remittent m. a malarial fever, usually of the severe falciparum type, in which the temperature falls but not to the normal level during the interval between two pronounced paroxysms.
- simian m. plasmodial infection of monkeys and apes, as with human m., transmitted chiefly by anopheline mosquitoes; a number of Plasmodium species are responsible, with Southeast Asia and Africa being the apparent centers of evolution; among the 20 plasmodial agents described from nonhuman primates, some resemble and induce a malarial infection similar to those caused by the four species of Plasmodium from humans, from which the agents of human m. appear to be derived. SYN: monkey m..
- tertian m. SYN: vivax m..
- therapeutic m. intentionally induced m., formerly used against neurosyphilis and certain other paralytic diseases. SYN: malariotherapy.
- vivax m. a malarial fever with paroxysms that typically recur every 48 hours or every other day (every third day, reckoning the day of the paroxysm as the first); the fever is induced by release of merozoites and their invasion of new red blood corpuscles. SYN: benign tertian fever, benign tertian m., tertian fever, tertian m., vivax fever.
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ma·lar·ia mə-'ler-ē-ə n
1) an acute or chronic disease caused by the presence of sporozoan parasites of the genus Plasmodium in the red blood cells, transmitted from an infected to an uninfected individual by the bite of anopheline mosquitoes, and characterized by periodic attacks of chills and fever that coincide with mass destruction of blood cells and the release of toxic substances by the parasite at the end of each reproductive cycle <\malaria remains the greatest single cause of debilitation and death throughout the world (Jour. Amer. Med. Assoc.)> see FALCIPARUM MALARIA, VIVAX MALARIA
2) any of various diseases of birds and mammals that are more or less similar to malaria of human beings and are caused by blood protozoans
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n.
an infectious disease due to the presence of parasitic protozoa of the genus Plasmodium (P. falciparum, P. malariae, P. ovale, or P. vivax) within the red blood cells. The disease is transmitted by the Anopheles mosquito and is confined mainly to tropical and subtropical areas.
Parasites in the blood of an infected person are taken into the stomach of the mosquito as it feeds. Here they multiply and then invade the salivary glands. When the mosquito bites an individual, parasites are injected into the bloodstream and migrate to the liver and other organs, where they multiply. After an incubation period varying from 12 days (P. falciparum) to 10 months (some varieties of P. vivax), parasites return to the bloodstream and invade the red blood cells. Rapid multiplication of the parasites results in destruction of the red cells and the release of more parasites capable of infecting other red cells. This causes a short bout of shivering, fever, and sweating, and the loss of healthy red cells results in anaemia. When the next batch of parasites is released symptoms reappear. The interval between fever attacks varies in different types of malaria: in quartan malaria (or fever), caused by P. malariae, it is three days; in tertian malaria (P. ovale or P. vivax) two days; and in malignant tertian (or quotidian) malaria (P. falciparum) - the most severe kind - from a few hours to two days (see also blackwater fever). Preventive and curative treatment includes such drugs as chloroquine, proguanil, mefloquine, and
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ma·la·ria (mə-larґe-ə) [It. “bad airâ€] an infectious disease endemic in many warm regions of the world, caused by obligate intracellular protozoa of the genus Plasmodium, usually transmitted by the bites of infected anopheline mosquitoes. It is characterized by prostration with paroxysms of high fever, shaking chills, sweating, anemia, and splenomegaly; death may result from its complications, the most severe of which are cerebral malaria and anemia. After the initial illness, it may follow a chronic or relapsing course. Called also paludism. malarial, malarious adjMedical dictionary. 2011.