Host-pathogen interactions under pressure: a review and meta-analysis of stress-mediated effects on disease dynamics

Human activities have increased the intensity and frequency of natural stressors and created novel stressors, altering host-pathogen interactions, and changing the risk of emerging infectious diseases. Despite the ubiquity of such anthropogenic impacts, predicting the directionality of outcomes has proven challenging. Here, we conduct a review and meta-analysis to determine the primary mechanisms through which stressors affect host-pathogen interactions and to evaluate the impacts stress has on host fitness (survival and fecundity) and pathogen infectivity (prevalence and intensity). We assessed 891 effect sizes from 71 host species (representing seven taxonomic groups) and 78 parasite taxa from 98 studies. We found that infected and uninfected hosts had similar sensitivity to stressors and that responses varied according to stressor type. Specifically, limited resources compromised host fecundity and decreased pathogen intensity, while abiotic environmental stressors (e.g., temperature..., We conducted a systematic literature search and meta-analysis to evaluate the impacts of three broad types of environmental stressors on disease dynamics. First, we confirmed that pathogen exposure in laboratory studies typically negatively affected host fitness. We then proceeded with our main meta-analyses focused on two specific questions: Q1) were stressor fitness effects more severe for infected vs. uninfected hosts?, and Q2) was infectivity more susceptible to environmental stress than host fitness traits? To address these questions with data from primary studies, we used infection intensity and prevalence as proxies for infectivity and survivorship and fecundity as proxies of host fitness.
To identify studies that evaluated the effects of environmental stressors on infectivity and host fitness traits in host-parasite systems, on February 9th of 2021, we conducted a systematic literature search in Web of Science using the search terms: (parasit* OR pathogen* OR disease) AND (envir..., , # Host-pathogen interactions under pressure: a systematic review and meta-analysis of stress-mediated effects on disease dynamics

Data from experimental research evaluating the effects of stress (resource limitation, environmental stress, and pollution) on host-parasite interactions. Empty cells are present because the screened papers only reported one or few statistics that could be recorded. Included is also the code for the meta-analysis evaluating the effects. Our code ignores the empty cells from the database.