BRIEF REPORT • JID 2004:190 (15 August) • 853
B R I E F R E P O R T
Molecular Diagnosis of Resistance
to Antimalarial Drugs during Epidemics
and in War Zones
Abdoulaye A. Djimde ´,1Amagana Dolo,1Amed Ouattara,1Sira Diakite ´,2
Christopher V. Plowe,3and Ogobara K. Doumbo1
1Malaria Research and Training Center, Department of Epidemiology of Parasitic
Diseases, Faculty of Medicine, Pharmacy, and Dentistry, University of Bamako,
3Malaria Section, Center for Vaccine Development, University of Maryland
School of Medicine, Baltimore
2National Malaria Control Program, Ministry of Health, Bamako, Mali;
Plasmodium falciparum mutations pfcrt K76T and the dhfr/
dhps “quintuple mutant” are molecular markersofresistance
to chloroquine and sulfadoxine-pyrimethamine,respectively.
During an epidemic of P. falciparum malaria in an area of
political unrest in northern Mali, where standard efficacy
studies have been impossible, we measured the prevalence
of these markers in a cross-sectional survey. In 80% of cases
of infection, pfcrt K76T was detected, but none of the cases
carried the dhfr/dhps quintuple mutant. On the basis of
these results, chloroquine was replaced by sulfadoxine-pyri-
methamine in control efforts. This example illustrates how
molecular markers for drug resistance can provide timely
data that inform malaria-control policy during epidemics
and other emergency situations.
Standard in vitro and in vivo studies of resistance to anti-
malarial drugs are time consuming and often difficult to in-
terpret in endemic settings where transmission is ongoing .
Furthermore, these methods are not feasible in emergencycon-
ditions, such as war zones, and for displaced populations .
The pfcrt K76T mutation is a molecular marker of resistance
Received 12 December 2003; accepted 11 March 2004; electronically published 15 July
Presented in part: 49th Annual Meeting of the American Society of Tropical Medicine and
Hygiene, Houston, Texas, 30 October 2000 (abstract 10).
Financial support: United Nations Development Programme (UNDP)/World Bank/World Health
Organization (WHO), Special Programme forTropical DiseaseResearch(TDR)/MultilateralInitiative
on Malaria (grant 980152); Department of Technical Cooperation, International Atomic Energy
Agency; UNDP/World Bank/WHO TDR Research Training Grant and NIH Research Fellowship
(both to A.A.D.).
Reprints or correspondence: Dr. Christopher V. Plowe, Center for Vaccine Development,
University of Maryland School of Medicine, 685 W. Baltimore St., HSF1 480, Baltimore, MD
The Journal of Infectious Diseases2004;190:853–5
? 2004 by the Infectious Diseases Society of America. All rights reserved.
to chloroquine . Age-adjusted ratios of the prevalence of this
marker to the prevalence of in vivo resistance to chloroquine
have been described as a practical means of using molecular
markers to estimate levels of resistance to chloroquine (i.e., the
genotype-resistance index [GRI]) . The prevalence of the
Plasmodium falciparum genotype with the “quintuple mutant”
is strongly associated with in vivo resistance to sulfadoxine-
pyrimethamine . This quintuple mutant includes theS108N,
N51I, and C59R mutations in the dihydrofolate reductase gene
(dhfr) and the A437G and K540E mutations in the dihydrop-
teroate synthase gene (dhps). We report the first use of molec-
ular markers of drug-resistant malaria in the management of
a malaria epidemic.
The study was conducted in October 1999 in
Kidal, a district of 42,500 people in the Sahara Desert in north-
ern Mali. The inhabitants are nomadic Touareg and Arab cattle
or after heavy rainfall. The region was emerging from a 10-
year rebellion that resulted in a disruption of all government
services, including health care. Although the average annual
rainfall is 100 mm, Kidal received 280 mm of rain in August
1999. During the following September, a sharp increase in the
number of cases of clinically suspected malaria (fever without
any other apparent cause) was reported to the Malian Ministry
of Health in Bamako (table 1).
Because land travel was not safe, staff from theMalianNation-
al Malaria Control Program (Bamako) and scientists from the
Malaria Research and Training Center (Bamako) were flown to
Kidal in a military plane. From 11 to 18 October 1999, epide-
miological and entomological surveys were done to assess the
epidemic, which was confirmed by microscopy to have been
caused by P. falciparum. Stocks of chloroquine and sulfadoxine-
pyrimethamine in the public sector and in private pharmacies
were measured. The lack of security prevented the use of con-
ventional methods of measuring resistance to antimalarialdrugs.
Under military escort, a cross-sectional survey was conducted in
5 nomadic camps. Eighty-seven suspected cases of malaria were
detected on the basis of clinical diagnoses. Thick and thin blood
smears were obtained for microscopy, and blood samples from
finger pricks were spotted onto filter-paper strips for molecular
analysis. The prevalences of molecular markers for resistance to
chloroquine and sulfadoxine-pyrimethamineweredeterminedas
described elsewhere [1, 3, 4]. Informed consent was obtained
from patients or their parents or guardians.
The inventory of drugs yielded 194,600 tablets of
chloroquine, 1748 bottles of chloroquine syrup, and 4254 am-
by guest on February 2, 2016