Do seasonal microbiome changes affect infection susceptibility, contributing to seasonal disease outbreaks?

Abstract

The aim of the present paper is to explore whether seasonal outbreaks of infectious diseases may be linked to changes in host microbiomes. This is a very important issue, because one way to have more control over seasonal outbreaks is to understand the factors that underlie them. In this paper, I will evaluate the relevance of the microbiome as one of such factors. The paper is based on two pillars of reasoning. Firstly, on the idea that microbiomes play an important role in their hosts' defence against infectious diseases. Secondly, on the idea that microbiomes are not stable, but change seasonally. These two ideas are combined in order to argue that seasonal changes in a given microbiome may influence the functionality of the host's immune system and consequently make it easier for infectious agents to infect the host at certain times of year. I will argue that, while this is only a theoretical possibility, certain studies may back up such claims. Furthermore, I will show that this does not necessarily contradict other hypotheses aimed at explaining seasonal outbreaks; in fact, it may even enhance them.

The Immunology Of Suicidal Behavior

“…Indeed, activation of IL13 alpha 1 receptor (IL-13Rα1) in the dopaminergic neurons of substantia nigra was found to increase the vulnerability of these cells to oxidative damage, likely predisposing to Parkinson's disease (PD) [25]. The human saliva and gut microbiomes were reported to undergo diurnal, seasonal as well as geographical variations that affect gene expression, including those of the MHC [26][27][28][29]. This is significant, as numerous epidemiological studies have reported a seasonal pattern of suicidal behavior (with counts peaking in the spring and declining in winter) probably coinciding with viral infections [30,31].…”

Global climate change, diet, and the complex relationship between human host and microbiome: Towards an integrated picture

“…[ 51–57 ] It follows that climate change‐induced modifications in diet or life‐style may also impact the host's health status, in line with recent suggestions. [ 58 ] Indeed, changes in the human gut microbiome (e.g., due to the increasing use of antibiotics in food production) have been associated with the genesis and progression of different disorders [ 59–61 ] such as autoimmune diseases, [ 62–65 ] cancer, [ 66 ] metabolic disorders (e.g., [ 60,67 ] ) and mental disorders, like depression, [ 68 ] via the so‐called “gut‐brain axis.” The molecular basis of this relationship as well as the range and strength of the linkages between a phenotype and a microbiome's composition and abundance remains, however, unclear. [ 69 ]…”

Infection by a eukaryotic gut parasite in wild Daphnia sp. associates with a distinct bacterial community

“…There is now an increased appreciation for the putative role of bacterial communities in natural epidemics of infectious diseases (Stencel, 2021). Infection by a parasite leads to disease-induced dysbiosis or progressive changes in the host's bacterial community structure, with late-stage infections typically correlating with a lower diversity of associated microbes (Chen, Ng, Wu, Chen, & Wang, 2017;Jani & Briggs, 2014;Lloyd & Pespeni, 2018;Nunez-Pons, Work, Angulo-Preckler, Moles, & Avila, 2018;Rosado et al, 2019) and an increased occurrence of opportunistic pathogens (Cornejo-Granados et al, 2017;Griffiths et al, 2019).…”

“…There is now an increased appreciation for the putative role of bacterial communities in natural epidemics of infectious diseases (Stencel 2021 ). Infection by a parasite leads to disease-induced dysbiosis or progressive changes in the host's bacterial community structure, with late-stage infections typically correlating with a lower diversity of associated microbes (Chen et al .…”