One of my [Micaela’s] primary interests is the intersection of chronobiology and infectious disease ecology. I have an active collaboration with Barbara Helm of the Institute of Biodiversity, Animal Health and Comparative Medicine at Glasgow University. Barbara and I have been developing ecological and evolutionary models for integrating biological rhythms (i.e., circadian and circannual rhythms) into the study of infectious disease ecology and evolution. We have a couple projects in the works, including a paper “The Influence of Biological Rhythms on Host-Parasite Interactions” which will be published in the June 2015 issue of Trends in Ecology & Evolution. PDF available here.

I also recently co-authored a paper “Disrupted Seasonal Biology Impacts Health, Food Security and Ecosystems” in Proceedings of the Royal Society B with a large international & interdisciplinary group of colleagues. This review focuses on the disruption of seasonal rhythms and the impact on health. PDF available here.

The timing of host and parasite activities falls in the intersection of environmental rhythms, host life history, host immune rhythms, and parasite rhythms. This intersection is embedded within geophysical rhythms, the diel and annual cycles.

The timing of host and parasite activities falls in the intersection of environmental rhythms, host life history, host immune rhythms, and parasite rhythms. This intersection is embedded within geophysical rhythms, the diel and annual cycles. (Art by M. Martinez)

Biological rhythms are ubiquitous in eukaryotes and govern processes ranging from circadian gene expression to seasonal life history. Exciting new research in immunology and chronobiology is revealing the rhythmic nature of immunity in animals, including humans. The picture that has emerged is that there are measurable effects of host circadian and seasonal rhythms on infection. A long-standing puzzle in infectious disease ecology has been to understand the mechanisms responsible for shaping the periodicity of infection, both within hosts—such as diel cycles of malaria parasite reproduction—and on the population level, including seasonal incidence, a feature of nearly all acute infections and macroparasitic diseases. It seems clear that biological rhythms are an important, but so far under-studied, contributor to host-parasite interactions. We are convinced that ecological and evolutionary perspectives can help clarify these interactions, and thereby contribute to a better understanding of disease patterns. 

 

Circannual cycles, which are endogenous seasonal rhythms, structure life history events including reproduction, hibernation, and migration. We seek to understand how these rhythms, and accompanying rhythms in the immune system influence infectious diseases.

Circannual cycles, which are endogenous seasonal rhythms, structure life history events including reproduction, hibernation, and migration. We seek to understand how life history rhythms, and accompanying rhythms in the immune system, influence the transmission and pathology of infectious diseases. (Art by M. Martinez)