The malaria parasite has an intrinsic clock

Copyright © 2020 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works http://www.sciencemag.org/about/science-licenses-journal-article-reuseThis is an article distributed under the terms of the Science Journals Default License.Malarial rhythmic fevers are the consequence of the synchronous bursting of red blood cells (RBCs) on completion of the malaria parasite asexual cell cycle. Here, we hypothesized that an intrinsic clock in the parasite Plasmodium chabaudi underlies the 24-hour-based rhythms of RBC bursting in mice. We show that parasite rhythms are flexible and lengthen to match the rhythms of hosts with long circadian periods. We also show that malaria rhythms persist even when host food intake is evenly spread across 24 hours, suggesting that host feeding cues are not required for synchrony. Moreover, we find that the parasite population remains synchronous and rhythmic even in an arrhythmic clock mutant host. Thus, we propose that parasite rhythms are generated by the parasite, possibly to anticipate its circadian environment.F.R.-F. is an Associate, I.K. is a Lab Manager II, and J.S.T. is an Investigator in the Howard Hughes Medical Institute. J.H.A. is supported by NIH NIA F32-AG064886 and NIH T32-HLO9701; E.B.K. by NIH R01-HL128538, K24-HL105664, and P01-AG009975 and the MGH Department of Neurology; and M.M.M. by PTDC/BIA-MOL/30112/2017 and PTDC/MED-IMU/28664/2017. M.M.M. is supported by FCT grants (PTDC/BIA-MOL/30112/2017 and PTDC/MED-IMU/28664/2017) and F.R.-F. by NIH NIGMS 1K99GM132557-01info:eu-repo/semantics/publishedVersio