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
SN - 0002-9637
VL - 58
SP - 176
EP - 182
JO - Journal. National Malaria Society
JF - Journal. National Malaria Society
IS - 2
ER -
