Editing Malaria (section)

===Recurrent malaria===
Symptoms of malaria can recur after varying symptom-free periods. Depending upon the cause, recurrence can be classified as either [[recrudescence]], [[relapse]], or reinfection. Recrudescence is when symptoms return after a symptom-free period due to failure to remove blood-stage parasites by adequate treatment.{{sfn|WHO|2015|p=4}} Relapse is when symptoms reappear after the parasites have been eliminated from the blood but have persisted as dormant [[Plasmodium#Life cycle|hypnozoites]]<ref>{{cite journal | vauthors = Markus MB | title = Malaria: origin of the term 'hypnozoite' | journal = Journal of the History of Biology | volume = 44 | issue = 4 | pages = 781–786 | date = 2011 | pmid = 20665090 | doi = 10.1007/s10739-010-9239-3 | s2cid = 1727294 }}</ref> in liver cells. Relapse commonly occurs between 8 and 24 weeks after the initial symptoms and is often seen in ''P.&nbsp;vivax'' and ''P.&nbsp;ovale'' infections.<ref name="Nadjm-2012"/> ''P.&nbsp;vivax'' malaria cases in [[temperate]] areas often involve [[overwintering]] by hypnozoites, with relapses beginning the year after the mosquito bite.<ref name="White-2011"/> Reinfection means that parasites were eliminated from the entire body but new parasites were then introduced. Reinfection cannot readily be distinguished from relapse and recrudescence, although recurrence of infection within two weeks of treatment ending is typically attributed to treatment failure.{{sfn|WHO|2015|p=41}} People may develop some [[premunity|immunity]] when exposed to frequent infections.<ref name="Tran-2012"/>