Plasmodium berghei NK65: studies on the effect of treatment duration and inoculum size on recrudescence.
Recrudescence of Plasmodium berghei NK65 infection was studied to examine factors affecting recrudescence. Treatment with a high dose of chloroquine did not prevent recrudescence, but an extended duration of treatment suppressed the frequency of recrudescence. Infection with a larger number of parasites also resulted in more frequent recrudescences. Recrudescent parasites were as sensitive to chloroquine as those before treatment. Splenectomized mice were administered carbon particles, infected, and treated with chloroquine. Recrudescence was significantly more frequent in these mice than in mice given a sham operation and PBS. The results do not suggest that merozoite stages escape the effect of chloroquine by 'hiding' in phagocytes, but that latent parasites such as dormant ring stages may cause recrudescence.
Nakazawa
Shusuke
S
Department of Protozoology, Institute of Tropical Medicine, Nagasaki University, Sakamoto 1-12-4, Nagasaki 852-8523, Japan. nakazawa@net.nagasaki-u.ac.jp
D000818:Animals; D000962:Antimalarials / Q000008:administration & dosage / Q000494:pharmacology / Q000627:therapeutic use*; D002738:Chloroquine / Q000008:administration & dosage / Q000494:pharmacology / Q000627:therapeutic use*; D004305:Dose-Response Relationship, Drug; D004912:Erythrocytes / Q000469:parasitology; D005260:Female; D007928:Lethal Dose 50; D008288:Malaria / Q000188:drug therapy* / Q000517:prevention & control; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D008808:Mice, Inbred CBA; D008813:Mice, Inbred ICR; D018512:Parasitemia / Q000188:drug therapy / Q000517:prevention & control; D010962:Plasmodium berghei / Q000187:drug effects / Q000472:pathogenicity*; D055502:Secondary Prevention; D013997:Time Factors
D000962:Antimalarials; D002738:Chloroquine