malaria

American Heritage® Dictionary of the English Language, Fourth Edition

1. n. An infectious disease characterized by cycles of chills, fever, and sweating, caused by a protozoan of the genus Plasmodium in red blood cells, which is transmitted to humans by the bite of an infected female anopheles mosquito.
2. n. Archaic Bad or foul air; miasma.

Century Dictionary and Cyclopedia

1. n. Air contaminated with some pathogenic substance from the soil; specifically, air impregnated with the poison producing intermittent and remittent fever.
2. n. The disease produced by the air thus poisoned. In a strict sense the word is a generic term designating intermittent and remittent fever and other affections, such as malarial nenralgia, due to the same cause. Malarial diseases in this sense prevail in all quarters of the globe except the coldest, and the infection of soil and air occurs in both uninhabited and populous regions. The disease is contracted by presence in the locality, and not from the sick, nor do the latter seem to transplant the infection to new places to which they may go. The disease may apparently be introduced into the body through water that is drunk as well as through the air. The development of the poison is favored by heat and moisture. Malarial diseases are apt to increase after the turning up of virgin soil. The poison seems to lie low in the atmosphere, but may be blown to adjacent heights. Besides the well-marked fevers, the malarial poison produces various and often ill-marked perversions of the general health, such as neuralgia, neuritis, anemia, digestive disturbances, and albuminuria. The anatomical effects of the malarial poison are enlargement of the spleen, sometimes excessive, darkening of the skin, and the presence of a dark pigment in the blood, in amorphous masses. There is found, moreover, in malarial blood a variety of peculiar living bodies which are supposed to be the various stages in the life-history of a single organism. This has been called the Plasmodium malariæ. All these forms of malaria are, as a rule, affected favorably by quinine, and to a less degree by certain other drugs, notably arsenic.
3. n. Numerous investigations made in recent years have established the fact that malaria is a disease resulting from the presence within the red blood-corpuscles of a protozoan parasite, the Hæmamœba malariæ, or Plasmodium malariæ. The parasite has two cycles of existence, one in the human body, the other in the body of a mosquito of the genus Anopheles (which see, with cut). In the blood, reproduction of the parasite occurs only by fission or segmentation; but in the stomach-wall of the mosquito, which it reaches in the blood sucked by this insect from the skin of the sick, sexual reproduction occurs, the parasite giving birth to a large number of exceedingly minute forms, called sporozoids. These make their way through the tissues of the mosquito to its salivary glands, whence they are injected into the blood of the human subject whom this infected mosquito stings. On reaching maturity in the blood, the protozoan invades the red blood-corpuscles, and so completes the two cycles of its existence. The malarial paroxysm of chill, fever, and sweating occurs at the time of invasion of the blood-cells by a new brood of the parasites, either those resulting from segmentation of the protozoan within the human blood-vessels or those reproduced sexually in the body of the mosquito and thence injected into man. There are three varieties of the Hæmamœba which are concerned in the production of the three varieties of malaria, tertian, quartan, and estivoautumnal or pernicious. Symptomatically, there are four forms of malaria: the intermittent, in which the interval between the paroxysms is fever-free; the remittent, in which the fever is continuous, but is marked by exacerbations with intercurrent chill and sweating; the pernicious or congestive form, in which the blood-poisoning is profound; and the chronic form, constituting what is called the malarial cachexia. See Laverania.

Wiktionary

1. n. A disease spread by mosquito, in which a protozoan, Plasmodium, multiplies in blood every few days.

GNU Webster's 1913

1. n. Archaic Air infected with some noxious substance capable of engendering disease; esp., an unhealthy exhalation from certain soils, as marshy or wet lands, producing fevers; miasma.
2. n. (Med.) A human disease caused by infection of red blood cells by a protozoan of the genus Plasmodium, giving rise to fever and chills and many other symptoms, characterized by their tendency to recur at definite and usually uniform intervals. The protozoal infection is usually transmitted from another infected individual by the bite of an Anopheles mosquito.

WordNet 3.0

1. n. an infective disease caused by sporozoan parasites that are transmitted through the bite of an infected Anopheles mosquito; marked by paroxysms of chills and fever