Enhanced transmission of drug-resistant parasites to mosquitoes following drug treatment in rodent malaria.
The evolution of drug resistant Plasmodium parasites is a major challenge to effective malaria control. In theory, competitive interactions between sensitive parasites and resistant parasites within infections are a major determinant of the rate at which parasite evolution undermines drug efficacy. Competitive suppression of resistant parasites in untreated hosts slows the spread of resistance; competitive release following treatment enhances it. Here we report that for the murine model Plasmodium chabaudi, co-infection with drug-sensitive parasites can prevent the transmission of initially rare resistant parasites to mosquitoes. Removal of drug-sensitive parasites following chemotherapy enabled resistant parasites to transmit to mosquitoes as successfully as sensitive parasites in the absence of treatment. We also show that the genetic composition of gametocyte populations in host venous blood accurately reflects the genetic composition of gametocytes taken up by mosquitoes. Our data demonstrate that, at least for this mouse model, aggressive chemotherapy leads to very effective transmission of highly resistant parasites that are present in an infection, the very parasites which undermine the long term efficacy of front-line drugs.
Center for Infectious Disease Dynamics, Departments of Biology and Entomology, The Pennsylvania State University, University Park, Pennsylvania, United States of America.
Andrew S
AS
Bell
Silvie
S
Huijben
Krijn P
KP
Paaijmans
Derek G
DG
Sim
Brian H K
BH
Chan
William A
WA
Nelson
Andrew F
AF
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D000818:Animals; D000852:Anopheles / Q000469:parasitology*; D017931:DNA Primers / Q000235:genetics; D004351:Drug Resistance; D005260:Female; D016014:Linear Models; D016015:Logistic Models; D008288:Malaria / Q000188:drug therapy* / Q000635:transmission*; D051379:Mice; D008810:Mice, Inbred C57BL; D059208:Parasite Load; D016788:Plasmodium chabaudi / Q000235:genetics*; D016133:Polymerase Chain Reaction; D011739:Pyrimethamine / Q000627:therapeutic use*; D060888:Real-Time Polymerase Chain Reaction
D017931:DNA Primers; D011739:Pyrimethamine