TY - JOUR

T1 - The differing impact of chloroquine and pyrimethamine/sulfadoxine upon the infectivity of malaria species to the mosquito vector

AU - Hogh, B

AU - Gamage-Mendis, A

AU - Butcher, G A

AU - Thompson, R

AU - Begtrup, K

AU - Mendis, C

AU - Enosse, S M

AU - Dgedge, M

AU - Barreto, J

AU - Eling, W

AU - Sinden, R E

PY - 1998/2

Y1 - 1998/2

N2 - Using serum or infected blood from Danish volunteers and Plasmodium falciparum-infected Mozambican patients, respectively, the impact of curative doses of chloroquine and pyrimethamine/sulfadoxine upon infectivity of P. falciparum to Anopheles arabiensis and An. gambiae or of P. berghei to An. stephensi was studied. Both treatments cleared circulating P. falciparum gametocytes within 28 days. Before this clearance, chloroquine enhanced infectivity to An. arabiensis, whereas pyrimethamine/sulfadoxine decreased infectivity. Patients harboring chloroquine-resistant parasites as opposed to -sensitive ones were 4.4 times more likely to have gametocytes following treatment. In contrast, pyrimethamine/sulfadoxine-resistant parasites were 1.9 times less likely to produce gametocytes. In laboratory infections using replicated P. berghei or P. falciparum preparations, serum from chloroquine-treated, uninfected, nonimmune volunteers enhanced gametocyte infectivity with increasing efficiency for 21 days following treatment, whereas pyrimethamine/sulfadoxine significantly suppressed infectivity. The observed enhancement in infectivity induced by the use of chloroquine combined with increased gametocytemias in chloroquine-resistant strains may in part explain the rapid spread of chloroquine resistance in endemic populations.

AB - Using serum or infected blood from Danish volunteers and Plasmodium falciparum-infected Mozambican patients, respectively, the impact of curative doses of chloroquine and pyrimethamine/sulfadoxine upon infectivity of P. falciparum to Anopheles arabiensis and An. gambiae or of P. berghei to An. stephensi was studied. Both treatments cleared circulating P. falciparum gametocytes within 28 days. Before this clearance, chloroquine enhanced infectivity to An. arabiensis, whereas pyrimethamine/sulfadoxine decreased infectivity. Patients harboring chloroquine-resistant parasites as opposed to -sensitive ones were 4.4 times more likely to have gametocytes following treatment. In contrast, pyrimethamine/sulfadoxine-resistant parasites were 1.9 times less likely to produce gametocytes. In laboratory infections using replicated P. berghei or P. falciparum preparations, serum from chloroquine-treated, uninfected, nonimmune volunteers enhanced gametocyte infectivity with increasing efficiency for 21 days following treatment, whereas pyrimethamine/sulfadoxine significantly suppressed infectivity. The observed enhancement in infectivity induced by the use of chloroquine combined with increased gametocytemias in chloroquine-resistant strains may in part explain the rapid spread of chloroquine resistance in endemic populations.

KW - Animals

KW - Anopheles/parasitology

KW - Antimalarials/pharmacokinetics

KW - Carrier State/drug therapy

KW - Chloroquine/pharmacokinetics

KW - Drug Combinations

KW - Drug Resistance

KW - Female

KW - Humans

KW - Insect Vectors/parasitology

KW - Malaria/drug therapy

KW - Malaria, Falciparum/drug therapy

KW - Mice

KW - Mozambique/epidemiology

KW - Plasmodium berghei/drug effects

KW - Plasmodium falciparum/drug effects

KW - Prevalence

KW - Pyrimethamine/pharmacokinetics

KW - Risk Factors

KW - Sulfadoxine/pharmacokinetics

M3 - Journal article

C2 - 9502601

VL - 58

SP - 176

EP - 182

JO - Journal. National Malaria Society

JF - Journal. National Malaria Society

SN - 0002-9637

IS - 2

ER -