Urban malaria in Dakar, Senegal: chemosusceptibility and genetic diversity of Plasmodium falciparum isolates.
The chemosusceptibility and genetic polymorphism of Plasmodium falciparum populations from 48 patients hospitalized for malaria at the Hospital Principal in Dakar, Senegal were investigated during the 2002 malaria transmission season. Sixty-two percent of the isolates collected were from patients with severe malaria and 38% were from patients with mild malaria. In vitro activities of chloroquine, quinine, cycloguanil, atovaquone, mefloquine, halofantrine, and artesunate were evaluated. The prevalence of mutations in the Plasmodium falciparum dihydrofolate reductase (dhfr) and dihyropteroate synthetase (dhps) genes and the P. falciparum chloroquine resistance transporter (Pfcrt) gene associated with cycloguanil, pyrimethamine, sulfadoxine, and chloroquine resistance were estimated. The genetic polymorphism of the parasite populations was evaluated by analysis of the highly polymorphic regions of merozoite surface protein 1 (msp1) block 2 and msp2. Seventy percent of the isolates were assessed by an in vitro assay. Fifty-two percent of the isolates were chloroquine resistant, 45% were cycloguanil resistant, and 24% were atovaquone resistant. Four percent had low susceptibility to quinine. The Pfcrt and dhfr mutations were associated with in vitro chloroquine- and antimetabolic drug-resistant isolates, respectively. Approximately 70% of the isolates contained two or more clones. Genetic diversity of P. falciparum was high. The prevalence of allelic family K1 of msp1 was 68%. Isolates of P. falciparum were highly resistant to chloroquine, cycloguanil and atovaquone. The transmission rate of malaria in Dakar is low but a high degree of genetic polymorphism can increase severe malaria, as shown by persons coming to Dakar from areas highly endemic for malaria. Areas with urban malaria should use vector control measures and efficient chemoprophylaxis for non-immune populations.
Henry
Maud
M
Unité de Recherche en Biologie et Epidémiologie Parasitaires, Institut de Médecine Tropicale du Service de Santé des Armées, Marseille, France.
Diallo
Ibrahima
I
Bordes
Julien
J
Ka
Sidy
S
Pradines
Bruno
B
Diatta
Bakary
B
M'Baye
Papa Sialou
PS
Sane
Mouhamadou
M
Thiam
Massamba
M
Gueye
Pape Mandoumbe
PM
Wade
Boubacar
B
Touze
Jean Etienne
JE
Debonne
Jean-Marc
JM
Rogier
Christophe
C
Fusai
Thierry
T
D000293:Adolescent; D000328:Adult; D000368:Aged; D000818:Animals; D000953:Antigens, Protozoan / Q000235:genetics; D000962:Antimalarials / Q000494:pharmacology*; D002648:Child; D002675:Child, Preschool; D004094:Dihydropteroate Synthase / Q000235:genetics; D005260:Female; D005787:Gene Frequency; D006801:Humans; D016778:Malaria, Falciparum / Q000469:parasitology*; D008297:Male; D008565:Membrane Proteins / Q000235:genetics; D026901:Membrane Transport Proteins; D020066:Merozoite Surface Protein 1 / Q000235:genetics; D008875:Middle Aged; D021261:Parasitic Sensitivity Tests / Q000379:methods; D010963:Plasmodium falciparum / Q000187:drug effects* / Q000235:genetics*; D011110:Polymorphism, Genetic; D015800:Protozoan Proteins / Q000235:genetics; D012675:Senegal; D014505:Urban Population
D000953:Antigens, Protozoan; D000962:Antimalarials; D008565:Membrane Proteins; D026901:Membrane Transport Proteins; D020066:Merozoite Surface Protein 1; C416369:PfCRT protein, Plasmodium falciparum; D015800:Protozoan Proteins; C065974:merozoite surface protein 2, Plasmodium; D004094:Dihydropteroate Synthase