Malaria, Vivax: Malaria caused by PLASMODIUM VIVAX. This form of malaria is less severe than MALARIA, FALCIPARUM, but there is a higher probability for relapses to occur. Febrile paroxysms often occur every other day.Malaria: A protozoan disease caused in humans by four species of the PLASMODIUM genus: PLASMODIUM FALCIPARUM; PLASMODIUM VIVAX; PLASMODIUM OVALE; and PLASMODIUM MALARIAE; and transmitted by the bite of an infected female mosquito of the genus ANOPHELES. Malaria is endemic in parts of Asia, Africa, Central and South America, Oceania, and certain Caribbean islands. It is characterized by extreme exhaustion associated with paroxysms of high FEVER; SWEATING; shaking CHILLS; and ANEMIA. Malaria in ANIMALS is caused by other species of plasmodia.Plasmodium vivax: A protozoan parasite that causes vivax malaria (MALARIA, VIVAX). This species is found almost everywhere malaria is endemic and is the only one that has a range extending into the temperate regions.Malaria, Falciparum: Malaria caused by PLASMODIUM FALCIPARUM. This is the severest form of malaria and is associated with the highest levels of parasites in the blood. This disease is characterized by irregularly recurring febrile paroxysms that in extreme cases occur with acute cerebral, renal, or gastrointestinal manifestations.Trypanosoma vivax: An active blood parasite that is present in practically all domestic animals in Africa, the West Indies, and parts of Central and South America. In Africa, the insect vector is the tsetse fly. In other countries, infection is by mechanical means indicating that the parasites have been introduced to these countries and have been able to maintain themselves in spite of the lack of a suitable intermediate host. It is a cause of nagana, the severity of which depends on the species affected.Antimalarials: Agents used in the treatment of malaria. They are usually classified on the basis of their action against plasmodia at different stages in their life cycle in the human. (From AMA, Drug Evaluations Annual, 1992, p1585)Malaria, Cerebral: A condition characterized by somnolence or coma in the presence of an acute infection with PLASMODIUM FALCIPARUM (and rarely other Plasmodium species). Initial clinical manifestations include HEADACHES; SEIZURES; and alterations of mentation followed by a rapid progression to COMA. Pathologic features include cerebral capillaries filled with parasitized erythrocytes and multiple small foci of cortical and subcortical necrosis. (From Adams et al., Principles of Neurology, 6th ed, p136)Plasmodium falciparum: A species of protozoa that is the causal agent of falciparum malaria (MALARIA, FALCIPARUM). It is most prevalent in the tropics and subtropics.Malaria Vaccines: Vaccines made from antigens arising from any of the four strains of Plasmodium which cause malaria in humans, or from P. berghei which causes malaria in rodents.Plasmodium: A genus of protozoa that comprise the malaria parasites of mammals. Four species infect humans (although occasional infections with primate malarias may occur). These are PLASMODIUM FALCIPARUM; PLASMODIUM MALARIAE; PLASMODIUM OVALE, and PLASMODIUM VIVAX. Species causing infection in vertebrates other than man include: PLASMODIUM BERGHEI; PLASMODIUM CHABAUDI; P. vinckei, and PLASMODIUM YOELII in rodents; P. brasilianum, PLASMODIUM CYNOMOLGI; and PLASMODIUM KNOWLESI in monkeys; and PLASMODIUM GALLINACEUM in chickens.Parasitemia: The presence of parasites (especially malarial parasites) in the blood. (Dorland, 27th ed)Anopheles: A genus of mosquitoes (CULICIDAE) that are known vectors of MALARIA.Primaquine: An aminoquinoline that is given by mouth to produce a radical cure and prevent relapse of vivax and ovale malarias following treatment with a blood schizontocide. It has also been used to prevent transmission of falciparum malaria by those returning to areas where there is a potential for re-introduction of malaria. Adverse effects include anemias and GI disturbances. (From Martindale, The Extra Pharmacopeia, 30th ed, p404)Protozoan Proteins: Proteins found in any species of protozoan.Antigens, Protozoan: Any part or derivative of any protozoan that elicits immunity; malaria (Plasmodium) and trypanosome antigens are presently the most frequently encountered.Chloroquine: The prototypical antimalarial agent with a mechanism that is not well understood. It has also been used to treat rheumatoid arthritis, systemic lupus erythematosus, and in the systemic therapy of amebic liver abscesses.Duffy Blood-Group System: A blood group consisting mainly of the antigens Fy(a) and Fy(b), determined by allelic genes, the frequency of which varies profoundly in different human groups; amorphic genes are common.Insect Vectors: Insects that transmit infective organisms from one host to another or from an inanimate reservoir to an animate host.DNA, Protozoan: Deoxyribonucleic acid that makes up the genetic material of protozoa.Mosquito Control: The reduction or regulation of the population of mosquitoes through chemical, biological, or other means.Endemic Diseases: The constant presence of diseases or infectious agents within a given geographic area or population group. It may also refer to the usual prevalence of a given disease with such area or group. It includes holoendemic and hyperendemic diseases. A holoendemic disease is one for which a high prevalent level of infection begins early in life and affects most of the child population, leading to a state of equilibrium such that the adult population shows evidence of the disease much less commonly than do children (malaria in many communities is a holoendemic disease). A hyperendemic disease is one that is constantly present at a high incidence and/or prevalence rate and affects all groups equally. (Last, A Dictionary of Epidemiology, 3d ed, p53, 78, 80)Papua New Guinea: A country consisting of the eastern half of the island of New Guinea and adjacent islands, including New Britain, New Ireland, the Admiralty Islands, and New Hanover in the Bismarck Archipelago; Bougainville and Buka in the northern Solomon Islands; the D'Entrecasteaux and Trobriand Islands; Woodlark (Murua) Island; and the Louisiade Archipelago. It became independent on September 16, 1975. Formerly, the southern part was the Australian Territory of Papua, and the northern part was the UN Trust Territory of New Guinea, administered by Australia. They were administratively merged in 1949 and named Papua and New Guinea, and renamed Papua New Guinea in 1971.Antibodies, Protozoan: Immunoglobulins produced in a response to PROTOZOAN ANTIGENS.Plasmodium malariae: A protozoan parasite that occurs primarily in subtropical and temperate areas. It is the causal agent of quartan malaria. As the parasite grows it exhibits little ameboid activity.Pyrimethamine: One of the FOLIC ACID ANTAGONISTS that is used as an antimalarial or with a sulfonamide to treat toxoplasmosis.Pregnancy Complications, Parasitic: The co-occurrence of pregnancy and parasitic diseases. The parasitic infection may precede or follow FERTILIZATION.Microscopy: The use of instrumentation and techniques for visualizing material and details that cannot be seen by the unaided eye. It is usually done by enlarging images, transmitted by light or electron beams, with optical or magnetic lenses that magnify the entire image field. With scanning microscopy, images are generated by collecting output from the specimen in a point-by-point fashion, on a magnified scale, as it is scanned by a narrow beam of light or electrons, a laser, a conductive probe, or a topographical probe.Plasmodium berghei: A protozoan parasite of rodents transmitted by the mosquito Anopheles dureni.Thailand: Formerly known as Siam, this is a Southeast Asian nation at the center of the Indochina peninsula. Bangkok is the capital city.Travel: Aspects of health and disease related to travel.Drug Resistance: Diminished or failed response of an organism, disease or tissue to the intended effectiveness of a chemical or drug. It should be differentiated from DRUG TOLERANCE which is the progressive diminution of the susceptibility of a human or animal to the effects of a drug, as a result of continued administration.Sulfadoxine: A long acting sulfonamide that is used, usually in combination with other drugs, for respiratory, urinary tract, and malarial infections.Malaria, Avian: Any of a group of infections of fowl caused by protozoa of the genera PLASMODIUM, Leucocytozoon, and Haemoproteus. The life cycles of these parasites and the disease produced bears strong resemblance to those observed in human malaria.Drug Combinations: Single preparations containing two or more active agents, for the purpose of their concurrent administration as a fixed dose mixture.Fluorenes: A family of diphenylenemethane derivatives.Parasitology: The study of parasites and PARASITIC DISEASES.Indonesia: A republic stretching from the Indian Ocean east to New Guinea, comprising six main islands: Java, Sumatra, Bali, Kalimantan (the Indonesian portion of the island of Borneo), Sulawesi (formerly known as the Celebes) and Irian Jaya (the western part of New Guinea). Its capital is Djakarta. The ethnic groups living there are largely Chinese, Arab, Eurasian, Indian, and Pakistani; 85% of the peoples are of the Islamic faith.Kenya: A republic in eastern Africa, south of ETHIOPIA, west of SOMALIA with TANZANIA to its south, and coastline on the Indian Ocean. Its capital is Nairobi.Culicidae: A family of the order DIPTERA that comprises the mosquitoes. The larval stages are aquatic, and the adults can be recognized by the characteristic WINGS, ANIMAL venation, the scales along the wing veins, and the long proboscis. Many species are of particular medical importance.Sporozoites: The product of meiotic division of zygotes in parasitic protozoa comprising haploid cells. These infective cells invade the host and undergo asexual reproduction producing MEROZOITES (or other forms) and ultimately gametocytes.Plasmodium knowlesi: A protozoan parasite from Southeast Asia that causes monkey malaria. It is naturally acquired by man in Malaysia and can also be transmitted experimentally to humans.Insecticides: Pesticides designed to control insects that are harmful to man. The insects may be directly harmful, as those acting as disease vectors, or indirectly harmful, as destroyers of crops, food products, or textile fabrics.Erythrocytes: Red blood cells. Mature erythrocytes are non-nucleated, biconcave disks containing HEMOGLOBIN whose function is to transport OXYGEN.Tanzania: A republic in eastern Africa, south of UGANDA and north of MOZAMBIQUE. Its capital is Dar es Salaam. It was formed in 1964 by a merger of the countries of TANGANYIKA and ZANZIBAR.AfricaMefloquine: A phospholipid-interacting antimalarial drug (ANTIMALARIALS). It is very effective against PLASMODIUM FALCIPARUM with very few side effects.Quinine: An alkaloid derived from the bark of the cinchona tree. It is used as an antimalarial drug, and is the active ingredient in extracts of the cinchona that have been used for that purpose since before 1633. Quinine is also a mild antipyretic and analgesic and has been used in common cold preparations for that purpose. It was used commonly and as a bitter and flavoring agent, and is still useful for the treatment of babesiosis. Quinine is also useful in some muscular disorders, especially nocturnal leg cramps and myotonia congenita, because of its direct effects on muscle membrane and sodium channels. The mechanisms of its antimalarial effects are not well understood.Insecticide-Treated Bednets: Lightweight meshwork fabric made of cotton, silk, polyester, nylon (polyamides), or other material impregnated with insecticide, having openings too small to allow entry of mosquitoes or other insects, thereby offering protection against insect bite and insect-borne diseases.Bedding and Linens: Articles of cloth, usually cotton or rayon and other synthetic or cotton-blend fabrics, used in households, hospitals, physicians' examining rooms, nursing homes, etc., for sheets, pillow cases, toweling, gowns, drapes, and the like.Mali: A country in western Africa, east of MAURITANIA and south of ALGERIA. Its capital is Bamako. From 1904-1920 it was known as Upper Senegal-Niger; prior to 1958, as French Sudan; 1958-1960 as the Sudanese Republic and 1959-1960 it joined Senegal in the Mali Federation. It became an independent republic in 1960.Plasmodium yoelii: A species of PLASMODIUM causing malaria in rodents.Seasons: Divisions of the year according to some regularly recurrent phenomena usually astronomical or climatic. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)Anopheles gambiae: A species of mosquito in the genus Anopheles and the principle vector of MALARIA in Africa.French Guiana: A French overseas department on the northeast coast of South America. Its capital is Cayenne. It was first settled by the French in 1604. Early development was hindered because of the presence of a penal colony. The name of the country and the capital are variants of Guyana, possibly from the native Indian Guarani guai (born) + ana (kin), implying a united and interrelated race of people. (From Webster's New Geographical Dictionary, 1988, p418 & Room, Brewer's Dictionary of Names, 1992, p195)Host-Parasite Interactions: The relationship between an invertebrate and another organism (the host), one of which lives at the expense of the other. Traditionally excluded from definition of parasites are pathogenic BACTERIA; FUNGI; VIRUSES; and PLANTS; though they may live parasitically.Ghana: A republic in western Africa, south of BURKINA FASO and west of TOGO. Its capital is Accra.ColombiaBlood: The body fluid that circulates in the vascular system (BLOOD VESSELS). Whole blood includes PLASMA and BLOOD CELLS.Vanuatu: A republic consisting of an island group in Melanesia, in the southwest Pacific Ocean. Its capital is Port-Vila. It was called New Hebrides until 1980. It was discovered in 1606 by the Portuguese, forgotten for 160 years, then visited by Bougainville in 1768 and Captain Cook in 1774. It was under joint British and French administration from 1906 until it became independent in 1980 under the name of Vanuatu. The name is native, meaning our land. (From Webster's New Geographical Dictionary, 1988, p833 & Room, Brewer's Dictionary of Names, 1992, p570)Insect Bites and Stings: Bites and stings inflicted by insects.Disease Eradication: Termination of all transmission of infection by global extermination of the infectious agent through surveillance and containment (From Porta, A Dictionary of Epidemiology, 5th ed).SesquiterpenesDiagnostic Tests, Routine: Diagnostic procedures, such as laboratory tests and x-rays, routinely performed on all individuals or specified categories of individuals in a specified situation, e.g., patients being admitted to the hospital. These include routine tests administered to neonates.Parasitic Sensitivity Tests: Tests that demonstrate the relative effectiveness of chemotherapeutic agents against specific parasites.Polymerase Chain Reaction: In vitro method for producing large amounts of specific DNA or RNA fragments of defined length and sequence from small amounts of short oligonucleotide flanking sequences (primers). The essential steps include thermal denaturation of the double-stranded target molecules, annealing of the primers to their complementary sequences, and extension of the annealed primers by enzymatic synthesis with DNA polymerase. The reaction is efficient, specific, and extremely sensitive. Uses for the reaction include disease diagnosis, detection of difficult-to-isolate pathogens, mutation analysis, genetic testing, DNA sequencing, and analyzing evolutionary relationships.Amodiaquine: A 4-aminoquinoline compound with anti-inflammatory properties.Parasite Load: Measure of the number of the PARASITES present in a host organism.Plasmodium chabaudi: A protozoan parasite of rodents transmitted by the mosquito Anopheles stephensi.Plasmodium cynomolgi: A protozoan parasite that occurs naturally in the macaque. It is similar to PLASMODIUM VIVAX and produces a type of malaria similar to vivax malaria (MALARIA, VIVAX). This species has been found to give rise to both natural and experimental human infections.CambodiaMauritania: A republic in western Africa, southwest of ALGERIA and west of MALI. Its capital is Nouakchott.Anemia: A reduction in the number of circulating ERYTHROCYTES or in the quantity of HEMOGLOBIN.Ethanolamines: AMINO ALCOHOLS containing the ETHANOLAMINE; (-NH2CH2CHOH) group and its derivatives.Melanesia: The collective name for the islands of the Pacific Ocean northeast of Australia, including NEW CALEDONIA; VANUATU; New Hebrides, Solomon Islands, Admiralty Islands, Bismarck Archipelago, FIJI, etc. Melanesia (from the Greek melas, black + nesos, island) is so called from the black color of the natives who are generally considered to be descended originally from the Negroid Papuans and the Polynesians or Malays. (From Webster's New Geographical Dictionary, 1988, p748 & Room, Brewer's Dictionary of Names, 1992, p344)Mosquito Nets: Free-standing or supported lightweight meshwork fabric made of cotton, silk, polyester or other material, having openings too small to allow entry of mosquitoes or other insects, thereby protecting against INSECT BITES; INSECT STINGS, and insect-borne diseases.Topography, Medical: The systematic surveying, mapping, charting, and description of specific geographical sites, with reference to the physical features that were presumed to influence health and disease. Medical topography should be differentiated from EPIDEMIOLOGY in that the former emphasizes geography whereas the latter emphasizes disease outbreaks.Prevalence: The total number of cases of a given disease in a specified population at a designated time. It is differentiated from INCIDENCE, which refers to the number of new cases in the population at a given time.Genes, Protozoan: The functional hereditary units of protozoa.Ethiopia: An independent state in eastern Africa. Ethiopia is located in the Horn of Africa and is bordered on the north and northeast by Eritrea, on the east by Djibouti and Somalia, on the south by Kenya, and on the west and southwest by Sudan. Its capital is Addis Ababa.Mozambique: A republic in southern Africa, south of TANZANIA, east of ZAMBIA and ZIMBABWE, bordered on the west by the Indian Ocean. Its capital is Maputo. It was formerly called Portuguese East Africa.Guyana: A republic in the north of South America, east of VENEZUELA and west of SURINAME. Its capital is Georgetown.Uganda: A republic in eastern Africa, south of SUDAN and west of KENYA. Its capital is Kampala.Disease Vectors: Invertebrates or non-human vertebrates which transmit infective organisms from one host to another.Fever: An abnormal elevation of body temperature, usually as a result of a pathologic process.Life Cycle Stages: The continuous sequence of changes undergone by living organisms during the post-embryonic developmental process, such as metamorphosis in insects and amphibians. This includes the developmental stages of apicomplexans such as the malarial parasite, PLASMODIUM FALCIPARUM.BrazilGabon: A republic in west equatorial Africa, south of CAMEROON and west of the CONGO. Its capital is Libreville.New Guinea: Originally an island of the Malay Archipelago, the second largest island in the world. It divided, West New Guinea becoming part of Indonesia and East New Guinea becoming Papua New Guinea.Senegal: A republic in western Africa, southwest of MAURITANIA and east of MALI. Its capital is Dakar.Genome, Protozoan: The complete genetic complement contained in a set of CHROMOSOMES in a protozoan.Burkina Faso: A republic in western Africa, south and east of MALI and west of NIGER. Its capital is Ouagadougou. It was formerly called Upper Volta until 1984.Chemoprevention: The use of chemical compounds to prevent the development of a specific disease.IndiaPeruSudan: A country in northeastern Africa. The capital is Khartoum.Gambia: A republic in western Africa, constituting an enclave within SENEGAL extending on both sides of the Gambia River. Its capital is Banjul, formerly Bathurst.Sri LankaInfant, Newborn: An infant during the first month after birth.Merozoite Surface Protein 1: A surface protein found on Plasmodium species which induces a T-cell response. The antigen is polymorphic, sharing amino acid sequence homology among PLASMODIUM FALCIPARUM; PLASMODIUM CHABAUDI; PLASMODIUM VIVAX; and PLASMODIUM YOELII.Plasmodium ovale: A species of protozoan parasite causing MALARIA. It is the rarest of the four species of PLASMODIUM infecting humans, but is common in West African countries and neighboring areas.Geography: The science dealing with the earth and its life, especially the description of land, sea, and air and the distribution of plant and animal life, including humanity and human industries with reference to the mutual relations of these elements. (From Webster, 3d ed)Rural Population: The inhabitants of rural areas or of small towns classified as rural.Tetrahydrofolate Dehydrogenase: An enzyme of the oxidoreductase class that catalyzes the reaction 7,8-dihyrofolate and NADPH to yield 5,6,7,8-tetrahydrofolate and NADPH+, producing reduced folate for amino acid metabolism, purine ring synthesis, and the formation of deoxythymidine monophosphate. Methotrexate and other folic acid antagonists used as chemotherapeutic drugs act by inhibiting this enzyme. (Dorland, 27th ed) EC 126.96.36.199.Incidence: The number of new cases of a given disease during a given period in a specified population. It also is used for the rate at which new events occur in a defined population. It is differentiated from PREVALENCE, which refers to all cases, new or old, in the population at a given time.Placenta Diseases: Pathological processes or abnormal functions of the PLACENTA.Rain: Water particles that fall from the ATMOSPHERE.Malawi: A republic in southern Africa east of ZAMBIA and MOZAMBIQUE. Its capital is Lilongwe. It was formerly called Nyasaland.Reagent Kits, Diagnostic: Commercially prepared reagent sets, with accessory devices, containing all of the major components and literature necessary to perform one or more designated diagnostic tests or procedures. They may be for laboratory or personal use.Benin: A republic in western Africa, south of NIGER and between TOGO and NIGERIA. Its capital is Porto-Novo. It was formerly called Dahomey. In the 17th century it was a kingdom in the southern area of Africa. Coastal footholds were established by the French who deposed the ruler by 1892. It was made a French colony in 1894 and gained independence in 1960. Benin comes from the name of the indigenous inhabitants, the Bini, now more closely linked with southern Nigeria (Benin City, a town there). Bini may be related to the Arabic bani, sons. (From Webster's New Geographical Dictionary, 1988, p136, 310 & Room, Brewer's Dictionary of Names, 1992, p60)Aotidae: A family of the New World monkeys inhabiting the forests of South and Central America. There is a single genus and several species occurring in this family, including AOTUS TRIVIRGATUS (Northern night monkeys).DDT: A polychlorinated pesticide that is resistant to destruction by light and oxidation. Its unusual stability has resulted in difficulties in residue removal from water, soil, and foodstuffs. This substance may reasonably be anticipated to be a carcinogen: Fourth Annual Report on Carcinogens (NTP-85-002, 1985). (From Merck Index, 11th ed)Korea: Former kingdom, located on Korea Peninsula between Sea of Japan and Yellow Sea on east coast of Asia. In 1948, the kingdom ceased and two independent countries were formed, divided by the 38th parallel.AfghanistanClimate: The longterm manifestations of WEATHER. (McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)Pyrethrins: The active insecticidal constituent of CHRYSANTHEMUM CINERARIIFOLIUM flowers. Pyrethrin I is the pyretholone ester of chrysanthemummonocarboxylic acid and pyrethrin II is the pyretholone ester of chrysanthemumdicarboxylic acid monomethyl ester.Molecular Sequence Data: Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.Cameroon: A republic in central Africa lying east of CHAD and the CENTRAL AFRICAN REPUBLIC and west of NIGERIA. The capital is Yaounde.Drug Therapy, Combination: Therapy with two or more separate preparations given for a combined effect.Pregnancy: The status during which female mammals carry their developing young (EMBRYOS or FETUSES) in utero before birth, beginning from FERTILIZATION to BIRTH.Sensitivity and Specificity: Binary classification measures to assess test results. Sensitivity or recall rate is the proportion of true positives. Specificity is the probability of correctly determining the absence of a condition. (From Last, Dictionary of Epidemiology, 2d ed)Africa South of the Sahara: All of Africa except Northern Africa (AFRICA, NORTHERN).Nigeria: A republic in western Africa, south of NIGER between BENIN and CAMEROON. Its capital is Abuja.Merozoites: Uninuclear cells or a stage in the life cycle of sporozoan protozoa. Merozoites, released from ruptured multinucleate SCHIZONTS, enter the blood stream and infect the ERYTHROCYTES.Glucosephosphate Dehydrogenase Deficiency: A disease-producing enzyme deficiency subject to many variants, some of which cause a deficiency of GLUCOSE-6-PHOSPHATE DEHYDROGENASE activity in erythrocytes, leading to hemolytic anemia.Insecticide Resistance: The development by insects of resistance to insecticides.Sequence Analysis, DNA: A multistage process that includes cloning, physical mapping, subcloning, determination of the DNA SEQUENCE, and information analysis.VenezuelaBurundi: A republic in eastern Africa bounded on the north by RWANDA and on the south by TANZANIA. Its capital is Bujumbura.Genetic Variation: Genotypic differences observed among individuals in a population.Polymorphism, Genetic: The regular and simultaneous occurrence in a single interbreeding population of two or more discontinuous genotypes. The concept includes differences in genotypes ranging in size from a single nucleotide site (POLYMORPHISM, SINGLE NUCLEOTIDE) to large nucleotide sequences visible at a chromosomal level.Schizonts: Multinucleate cells or a stage in the development of sporozoan protozoa. It is exemplified by the life cycle of PLASMODIUM FALCIPARUM in the MALARIA infection cycle.Communicable Disease Control: Programs of surveillance designed to prevent the transmission of disease by any means from person to person or from animal to man.Angola: A republic in southern Africa, southwest of DEMOCRATIC REPUBLIC OF THE CONGO and west of ZAMBIA. Its capital is Luanda.Artemisinins: A group of SESQUITERPENES and their analogs that contain a peroxide group (PEROXIDES) within an oxepin ring (OXEPINS).VietnamEnzyme-Linked Immunosorbent Assay: An immunoassay utilizing an antibody labeled with an enzyme marker such as horseradish peroxidase. While either the enzyme or the antibody is bound to an immunosorbent substrate, they both retain their biologic activity; the change in enzyme activity as a result of the enzyme-antibody-antigen reaction is proportional to the concentration of the antigen and can be measured spectrophotometrically or with the naked eye. Many variations of the method have been developed.Genotype: The genetic constitution of the individual, comprising the ALLELES present at each GENETIC LOCUS.Permethrin: A pyrethroid insecticide commonly used in the treatment of LICE INFESTATIONS and SCABIES.Military Personnel: Persons including soldiers involved with the armed forces.Eritrea: A country of eastern Africa, west of the Red Sea, bordered west and northwest by SUDAN, and south by ETHIOPIA. Its capital is Asmara.Entomology: A discipline or occupation concerned with the study of INSECTS, including the biology and the control of insects.QuinolinesOceania: The islands of the central and South Pacific, including Micronesia, Melanesia, Polynesia, and traditionally Australasia. (Random House Dictionary, 2d ed)Cross-Sectional Studies: Studies in which the presence or absence of disease or other health-related variables are determined in each member of the study population or in a representative sample at one particular time. This contrasts with LONGITUDINAL STUDIES which are followed over a period of time.Recurrence: The return of a sign, symptom, or disease after a remission.Asia, Southeastern: The geographical area of Asia comprising BORNEO; BRUNEI; CAMBODIA; INDONESIA; LAOS; MALAYSIA; the MEKONG VALLEY; MYANMAR (formerly Burma), the PHILIPPINES; SINGAPORE; THAILAND; and VIETNAM.Republic of Korea: The capital is Seoul. The country, established September 9, 1948, is located on the southern part of the Korean Peninsula. Its northern border is shared with the Democratic People's Republic of Korea.Zambia: A republic in southern Africa, south of DEMOCRATIC REPUBLIC OF THE CONGO and TANZANIA, and north of ZIMBABWE. Its capital is Lusaka. It was formerly called Northern Rhodesia.Immunoglobulin G: The major immunoglobulin isotype class in normal human serum. There are several isotype subclasses of IgG, for example, IgG1, IgG2A, and IgG2B.Rural Health: The status of health in rural populations.Coma: A profound state of unconsciousness associated with depressed cerebral activity from which the individual cannot be aroused. Coma generally occurs when there is dysfunction or injury involving both cerebral hemispheres or the brain stem RETICULAR FORMATION.Azure Stains: PHENOTHIAZINES with an amino group at the 3-position that are green crystals or powder. They are used as biological stains.Madagascar: One of the Indian Ocean Islands off the southeast coast of Africa. Its capital is Antananarivo. It was formerly called the Malagasy Republic. Discovered by the Portuguese in 1500, its history has been tied predominantly to the French, becoming a French protectorate in 1882, a French colony in 1896, and a territory within the French union in 1946. The Malagasy Republic was established in the French Community in 1958 but it achieved independence in 1960. Its name was changed to Madagascar in 1975. (From Webster's New Geographical Dictionary, 1988, p714)Parasites: Invertebrate organisms that live on or in another organism (the host), and benefit at the expense of the other. Traditionally excluded from definition of parasites are pathogenic BACTERIA; FUNGI; VIRUSES; and PLANTS; though they may live parasitically.Oocysts: Zygote-containing cysts of sporozoan protozoa. Further development in an oocyst produces small individual infective organisms called SPOROZOITES. Then, depending on the genus, the entire oocyst is called a sporocyst or the oocyst contains multiple sporocysts encapsulating the sporozoites.Africa, Western: The geographical area of Africa comprising BENIN; BURKINA FASO; COTE D'IVOIRE; GAMBIA; GHANA; GUINEA; GUINEA-BISSAU; LIBERIA; MALI; MAURITANIA; NIGER; NIGERIA; SENEGAL; SIERRA LEONE; and TOGO.Folic Acid Antagonists: Inhibitors of the enzyme, dihydrofolate reductase (TETRAHYDROFOLATE DEHYDROGENASE), which converts dihydrofolate (FH2) to tetrahydrofolate (FH4). They are frequently used in cancer chemotherapy. (From AMA, Drug Evaluations Annual, 1994, p2033)Treatment Outcome: Evaluation undertaken to assess the results or consequences of management and procedures used in combating disease in order to determine the efficacy, effectiveness, safety, and practicability of these interventions in individual cases or series.RNA, Protozoan: Ribonucleic acid in protozoa having regulatory and catalytic roles as well as involvement in protein synthesis.Trophozoites: Cells or feeding stage in the life cycle of sporozoan protozoa. In the malarial parasite, the trophozoite develops from the MEROZOITE and then splits into the SCHIZONT. Trophozoites that are left over from cell division can go on to form gametocytes.Splenomegaly: Enlargement of the spleen.Time Factors: Elements of limited time intervals, contributing to particular results or situations.Population Surveillance: Ongoing scrutiny of a population (general population, study population, target population, etc.), generally using methods distinguished by their practicability, uniformity, and frequently their rapidity, rather than by complete accuracy.Coinfection: Simultaneous infection of a host organism by two or more pathogens. In virology, coinfection commonly refers to simultaneous infection of a single cell by two or more different viruses.Djibouti: A republic in eastern Africa, on the Gulf of Aden at the entrance to the Red Sea. Djibouti is also the name of its capital.Equatorial Guinea: A republic in central Africa, bordering the Bay of Biafra, CAMEROON is to the north and GABON to the south. Its capital is Malabo.Amino Acid Sequence: The order of amino acids as they occur in a polypeptide chain. This is referred to as the primary structure of proteins. It is of fundamental importance in determining PROTEIN CONFORMATION.Population Density: Number of individuals in a population relative to space.RNA, Ribosomal, 18S: Constituent of the 40S subunit of eukaryotic ribosomes. 18S rRNA is involved in the initiation of polypeptide synthesis in eukaryotes.Pregnancy Complications, Infectious: The co-occurrence of pregnancy and an INFECTION. The infection may precede or follow FERTILIZATION.Travel Medicine: Multidisciplinary field focusing on prevention of infectious diseases and patient safety during international TRAVEL. Key element of patient's pre-travel visit to the physician is a health risk assessment.HondurasAminoquinolines: Quinolines substituted in any position by one or more amino groups.L-Lactate Dehydrogenase: A tetrameric enzyme that, along with the coenzyme NAD+, catalyzes the interconversion of LACTATE and PYRUVATE. In vertebrates, genes for three different subunits (LDH-A, LDH-B and LDH-C) exist.Asymptomatic Infections: Infections that do not exhibit symptoms.Epidemiological Monitoring: Collection, analysis, and interpretation of data about the frequency, distribution, and consequences of disease or health conditions, for use in the planning, implementing, and evaluating public health programs.Proguanil: A biguanide compound which metabolizes in the body to form cycloguanil, an anti-malaria agent.Clinical Laboratory Techniques: Techniques used to carry out clinical investigative procedures in the diagnosis and therapy of disease.Dihydropteroate Synthase: An enzyme that catalyzes the formation of dihydropteroate from p-aminobenzoic acid and dihydropteridine-hydroxymethyl-pyrophosphate. EC 188.8.131.52.Disease Transmission, Infectious: The transmission of infectious disease or pathogens. When transmission is within the same species, the mode can be horizontal or vertical (INFECTIOUS DISEASE TRANSMISSION, VERTICAL).PakistanSickle Cell Trait: The condition of being heterozygous for hemoglobin S.Hemoglobins: The oxygen-carrying proteins of ERYTHROCYTES. They are found in all vertebrates and some invertebrates. The number of globin subunits in the hemoglobin quaternary structure differs between species. Structures range from monomeric to a variety of multimeric arrangements.Inhibitory Concentration 50: The concentration of a compound needed to reduce population growth of organisms, including eukaryotic cells, by 50% in vitro. Though often expressed to denote in vitro antibacterial activity, it is also used as a benchmark for cytotoxicity to eukaryotic cells in culture.Alleles: Variant forms of the same gene, occupying the same locus on homologous CHROMOSOMES, and governing the variants in production of the same gene product.Tropical Climate: A climate which is typical of equatorial and tropical regions, i.e., one with continually high temperatures with considerable precipitation, at least during part of the year. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)Trypanosomiasis: Infection with protozoa of the genus TRYPANOSOMA.Placenta: A highly vascularized mammalian fetal-maternal organ and major site of transport of oxygen, nutrients, and fetal waste products. It includes a fetal portion (CHORIONIC VILLI) derived from TROPHOBLASTS and a maternal portion (DECIDUA) derived from the uterine ENDOMETRIUM. The placenta produces an array of steroid, protein and peptide hormones (PLACENTAL HORMONES).Polymorphism, Restriction Fragment Length: Variation occurring within a species in the presence or length of DNA fragment generated by a specific endonuclease at a specific site in the genome. Such variations are generated by mutations that create or abolish recognition sites for these enzymes or change the length of the fragment.Receptors, Cell Surface: Cell surface proteins that bind signalling molecules external to the cell with high affinity and convert this extracellular event into one or more intracellular signals that alter the behavior of the target cell (From Alberts, Molecular Biology of the Cell, 2nd ed, pp693-5). Cell surface receptors, unlike enzymes, do not chemically alter their ligands.Insect Repellents: Substances causing insects to turn away from them or reject them as food.Disease Outbreaks: Sudden increase in the incidence of a disease. The concept includes EPIDEMICS and PANDEMICS.Risk Factors: An aspect of personal behavior or lifestyle, environmental exposure, or inborn or inherited characteristic, which, on the basis of epidemiologic evidence, is known to be associated with a health-related condition considered important to prevent.Refugees: Persons fleeing to a place of safety, especially those who flee to a foreign country or power to escape danger or persecution in their own country or habitual residence because of race, religion, or political belief. (Webster, 3d ed)Indians, South American: Individual members of South American ethnic groups with historic ancestral origins in Asia.Atlantic Islands: Widely scattered islands in the Atlantic Ocean as far north as the AZORES and as far south as the South Sandwich Islands, with the greatest concentration found in the CARIBBEAN REGION. They include Annobon Island, Ascension, Canary Islands, Falkland Islands, Fernando Po (also called Isla de Bioko and Bioko), Gough Island, Madeira, Sao Tome and Principe, Saint Helena, and Tristan da Cunha.Hemeproteins: Proteins that contain an iron-porphyrin, or heme, prosthetic group resembling that of hemoglobin. (From Lehninger, Principles of Biochemistry, 1982, p480)Species Specificity: The restriction of a characteristic behavior, anatomical structure or physical system, such as immune response; metabolic response, or gene or gene variant to the members of one species. It refers to that property which differentiates one species from another but it is also used for phylogenetic levels higher or lower than the species.Guinea: A republic in western Africa, south of SENEGAL and MALI, east of GUINEA-BISSAU. Its capital is Conakry.Treatment Failure: A measure of the quality of health care by assessment of unsuccessful results of management and procedures used in combating disease, in individual cases or series.Vaccines, Synthetic: Small synthetic peptides that mimic surface antigens of pathogens and are immunogenic, or vaccines manufactured with the aid of recombinant DNA techniques. The latter vaccines may also be whole viruses whose nucleic acids have been modified.