Falciparum malaria in the north of Laos: the occurrence and implications of the Plasmodium falciparum chloroquine resistance transporter (pfcrt) gene haplotype SVMNT.
OBJECTIVE
The Pfcrt-gene encodes a transmembrane protein located in the Plasmodium falciparum digestive vacuole. Chloroquine resistant (CQR) strains of African and Southeast Asian origin carry the Pfcrt-haplotype (c72-76) CVIET, whereas most South American and Papua New Guinean CQR stains carry the SVMNT haplotype.


METHODS
Eighty-eight samples from an area with reported in vivo Chloroquine and in vitro Amodiaquine-resistance were screened for the K76T mutation and their Pfcrt-haplotype (c72-76) using a new SSOP-ELISA.


RESULTS
Hundred percent of the analysed samples showed the K76T mutation which is highly associated with in vivo drug failure. This very high rate of a CQR-marker is alarming in an area were CQ is still used as first line drug. The distribution of the three main Pfcrt-haplotypes was as follows: 68% CVIET, 31% SVMNT, 0% CVMNT.


CONCLUSIONS
These data show, for the first time, the South American/PNG -haplotype (SVMNT) on mainland Southeast Asia. SVMNT-haplotype and others might be associated with a decreased efficacy of Amodiaquine and could therefore be potential markers for of amodiaquine resistance (AQR). If there is a correlation between AQR and the SVMNT-haplotype as suggested, 31% prevalence of a potential resistance marker is cause for concern.
Dittrich
Sabine
S
Institute of Tropical Medicine, Berlin, Germany.
Alifrangis
Michael
M
Stohrer
Jörg M
JM
Thongpaseuth
Vonthalom
V
Vanisaveth
Viengxay
V
Phetsouvanh
Rattanaxay
R
Phompida
Samlane
S
Khalil
Insaf F
IF
Jelinek
Tomas
T
D000293:Adolescent; D000328:Adult; D000368:Aged; D000818:Animals; D000962:Antimalarials / Q000627:therapeutic use; D002648:Child; D002675:Child, Preschool; D002738:Chloroquine / Q000627:therapeutic use; D003430:Cross-Sectional Studies; D004351:Drug Resistance / Q000235:genetics; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D005260:Female; D006239:Haplotypes / Q000235:genetics; D006801:Humans; D007812:Laos / Q000453:epidemiology; D016778:Malaria, Falciparum / Q000188:drug therapy / Q000453:epidemiology / Q000235:genetics*; D008297:Male; D008565:Membrane Proteins / Q000235:genetics*; D026901:Membrane Transport Proteins; D008875:Middle Aged; D009154:Mutation / Q000235:genetics; D009693:Nucleic Acid Hybridization / Q000379:methods; D010963:Plasmodium falciparum / Q000235:genetics*; D015800:Protozoan Proteins; D017211:Treatment Failure
D000962:Antimalarials; D008565:Membrane Proteins; D026901:Membrane Transport Proteins; C416369:PfCRT protein, Plasmodium falciparum; D015800:Protozoan Proteins; D002738:Chloroquine