Many parasitic infections show rhythmic daily patterns. Malaria blood-stage parasites have a synchronous asexual cycle, with a coordinated cycle from the moment of invasion of the red blood cells until their bursting. This cycle lasts 24 hours or multiples of 24 hours, depending on the species, and is associated with recurrent fevers in the host. The human infectious stage of the Schistosoma mansoni parasite (known as cercariae forms) emerges from snails and swims in fresh water to infect humans by penetrating through the skin. Interestingly, the emergence of this infectious stage is rhythmic and matches the behavior of its final host: occurring during the daytime in parasites that infect humans and in the early evening in parasites that infect nocturnal rats.

This work was supported by an HHMI International Early Career Scientist award (55007419, to LMF) and Fundação para a Ciência e Tecnologia award (IF/01050/2014 to LMF). JST is an Investigator in the Howard Hughes Medical Institute. FRF is a Research Associate in the Howard Hughes Medical Institute. HHMI: http://www.hhmi.org; FCT: http://www.fct.pt.

Copyright: © 2017 Rijo-Ferreira et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.