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Chloroquine-susceptible and -resistant parasites recrudesced after 3 and 5 days of chloroquine exposure. Recrudescence occurred in one out of four 7 day exposure series but not after 14 days exposure. The median time to recrudescence was 13 to 28 days with a range of 8 to 41 days after the end of exposure. Time to recrudescence after the end of exposure increased with duration of exposure for susceptible and resistant strains (P &amp;lt; 0.001). Time to recrudescence did not correlate with concentrations greater than 1\u00d7 IC90.<\/jats:p><\/jats:sec><jats:sec><jats:title>Conclusions<\/jats:title><jats:p>Chloroquine-susceptible and -resistant P. falciparum probably become dormant. Elimination of dormant parasites is primarily dependent upon the duration of chloroquine exposure. Exposure to effective drug concentrations for 7 days eliminates most parasites in vitro. The results support in vivo data indicating that elimination of chloroquine-resistant P. falciparum correlates with Day 7 chloroquine concentrations.<\/jats:p><\/jats:sec>","DOI":"10.1093\/jac\/dkac008","type":"journal-article","created":{"date-parts":[[2022,1,16]],"date-time":"2022-01-16T20:06:05Z","timestamp":1642363565000},"page":"1005-1011","source":"Crossref","is-referenced-by-count":5,"title":["Chloroquine-susceptible and -resistant<i>Plasmodium falciparum<\/i>strains survive high chloroquine concentrations by becoming dormant but are eliminated by prolonged exposure"],"prefix":"10.1093","volume":"77","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-5508-9327","authenticated-orcid":false,"given":"Johan","family":"Ursing","sequence":"first","affiliation":[{"name":"Projecto de Sa\u00fade de Bandim, Indepth Network, Bissau, Guinea-Bissau"},{"name":"Department of Clinical Sciences, Karolinska Institutet, Stockholm, Sweden"},{"name":"Department of Infectious Diseases, Danderyd 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