Circadian rhythms seem to play a crucial role in how vulnerable one is to malaria parasites.
Research conducted by scientists affiliated with McGill University may lead to improved treatments for malaria and other parasitic illnesses.
The findings revealed by research groups from McGill University, the Douglas Research Centre, and the Research Institute of the McGill University Health Centre indicate that when mice are infected with parasites that cause cerebral malaria at midnight, the disease’s symptoms are milder compared to infections that occur during the daytime. Furthermore, the parasites propagate less aggressively in these hosts.
Malaria, which is transmitted by mosquitoes, affects millions globally and results in over half a million deaths annually, with the majority being children. Cerebral malaria represents the most lethal variety of this disease.
These researchers’ discoveries could pave the way for new treatment protocols that coordinate medication with our natural body clocks.
The interaction between the circadian rhythms of hosts and parasites
Circadian rhythms are essentially the physiological and behavioral fluctuations that cycle roughly every 24 hours, aligning with the Earth’s rotation, and continue even without external timing cues. A primary clock in the brain, along with smaller clocks in various organs and cells, regulates these rhythms.
“We investigated how the circadian patterns of both the host and the malaria parasite interact to affect the disease’s severity and the host’s immune response to the parasite,” stated Priscilla Carvalho Cabral, a recent McGill PhD graduate involved in two new studies on this topic.
Nicolas Cermakian, who heads the Laboratory of Molecular Chronobiology and is the lead author of these studies, commented, “The variability in the host’s reaction to infection based on the time of day indicates that their circadian rhythms could be influencing the disease’s development. This aspect of immune clocks’ impact on malaria hasn’t been explored previously.”
A significant leap in understanding
Within parasites and their animal hosts, as well as in most organisms, various physiological functions operate under circadian regulation. For instance, the replication of malaria parasites within a host’s red blood cells follows a daily cycle. Earlier research from this group has shown that the serious parasitic disease leishmaniasis is affected by the host’s internal clocks, with the timing of infection impacting both the parasite’s replication and the host’s immune response. The new studies have found similar effects concerning cerebral malaria.
“Our findings mark a crucial advancement in understanding since many of the factors that influence susceptibility to diseases, particularly parasitic ones, are still largely unknown,” explains Martin Olivier, Director of the Laboratory for the Study of Host-Parasite Interaction and a professor in McGill’s Department of Microbiology and Immunology, who co-authored the studies.
