title: Chemotherapy of malaria and resistance to antimalarial drugs in Guayana area, Venezuela.
abstract: Resistance to antimalarial chemotherapy is one of the greatest difficulties for the control of malaria transmission. Seventy patients with Plasmodium falciparum malaria were included in a study of resistance to chloroquine and sulfadoxine-pyrimethamine therapy. Resistance levels RI, RII, and RIII were established. Eighteen infections (51%) cleared after chloroquine treatment and did not recur within 28 days of follow-up; these were classified as sensitive. Ten infections (29%) were resistant at the RI level. Resistance at level RII was observed in 5 (14%) cases, and RIII resistance was demonstrated in 2 infections (6%). With sulfadoxine-pyrimethamine, 28 (80%) infections were classified as sensitive. Six infections (17%) showed resistance at level RII, and 1 (3%) infection was resistant at the RI level. Resistance at level RIII was not observed. In a microtest for chloroquine and sulfadoxine-pyrimethamine sensitivity in vitro, schizont development was accomplished successfully in 70 blood samples. In vitro resistance to chloroquine was demonstrated in 15 of 70 (21%) of all isolates. Eight of 70 (11%) of all isolates showed resistance to sulfadoxine-pyrimethamine. Diversity of response of P. falciparum to the studied antimalarial drugs in the Guayana area of Venezuela is considered a problem restricting the control of malaria in this geographical area. A constant evaluation program monitoring P. falciparum drug sensitivity is necessary for preserving the efficacy of the established treatment.
authors.affiliation: Ministerio de Sanidad, Instituto de Salud Pública, Malariología, Caracas, Venezuela.
authors.forename: A
authors.initials: A
authors.lastname: Caraballo
authors.forename: A
authors.initials: A
authors.lastname: Rodriguez-Acosta
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000818:Animals; D000962:Antimalarials / Q000008:administration & dosage / Q000627:therapeutic use*; D002738:Chloroquine / Q000008:administration & dosage / Q000627:therapeutic use*; D004305:Dose-Response Relationship, Drug; D004338:Drug Combinations; D004351:Drug Resistance; D005260:Female; D006801:Humans; D007962:Leukocytes / Q000469:parasitology; D016778:Malaria, Falciparum / Q000188:drug therapy*; D008297:Male; D008875:Middle Aged; D018512:Parasitemia / Q000097:blood; D010963:Plasmodium falciparum / Q000187:drug effects*; D011739:Pyrimethamine / Q000008:administration & dosage / Q000627:therapeutic use*; D011897:Random Allocation; D012044:Regression Analysis; D012424:Rural Population; D013413:Sulfadoxine / Q000008:administration & dosage / Q000627:therapeutic use*; D014329:Tropical Climate; D014687:Venezuela
chemical_list: D000962:Antimalarials; D004338:Drug Combinations; C001205:fanasil, pyrimethamine drug combination; D013413:Sulfadoxine; D002738:Chloroquine; D011739:Pyrimethamine