Identifying climate drivers of infectious disease dynamics: recent advances and challenges ahead

Abstract

Climate change is likely to profoundly modulate the burden of infectious diseases. However, attributing health impacts to a changing climate requires being able to associate changes in infectious disease incidence with the potentially complex influences of climate. This aim is further complicated by nonlinear feedbacks inherent in the dynamics of many infections, driven by the processes of immunity and transmission. Here, we detail the mechanisms by which climate drivers can shape infectious disease incidence, from direct effects on vector life history to indirect effects on human susceptibility, and detail the scope of variation available with which to probe these mechanisms. We review approaches used to evaluate and quantify associations between climate and infectious disease incidence, discuss the array of data available to tackle this question, and detail remaining challenges in understanding the implications of climate change for infectious disease incidence. We point to areas where synthesis between approaches used in climate science and infectious disease biology provide potential for progress.

Thermal biology of mosquito‐borne disease

“…Temperature defines one dimension of the fundamental ecological niche for mosquito-borne disease transmissionthe range of conditions that is required for transmission to be possiblewhich also includes immature vector habitat and humidity. Within this fundamental niche, the realised ecological niche for transmission additionally depends on host factors including density, movement, behaviour, demography, susceptibility, control strategies, and exposure to mosquito bites (Gething et al 2010;Rodriguez-Barraquer et al 2011;Paaijmans & Thomas 2011a;Parham et al 2015;Wesolowski et al 2015;Krisher et al 2016;Metcalf et al 2017;Salje et al 2017Salje et al , 2018Jaramillo-Ochoa et al 2019). Mosquito and pathogen physiological responses to temperature determine fundamental transmission potential, but the realised impact of climate change on disease dynamics also depends on these host population processes, socio-economics, disease control efforts, or other mitigation measures (Gething et al 2010;Paaijmans & Thomas 2011a;Parham et al 2015;Wesolowski et al 2017).…”

Long-term trends in seasonality of mortality in urban Madagascar: the role of the epidemiological transition

“…depression), or exposure to pollutants [5]. For infectious diseases, climatic variables may drive additional seasonality for a range of pathogens, via their effects on vector life-cycles, how infectious particles fall out of the air for directly transmitted pathogens or by how flooding shapes transmission of water-borne infections [6]. Seasonal patterns of human behavior have also been shown to be a key driver of infections, with seasonal aggregation due to school terms [7] or seasonal migration [8] increasing the magnitude of measles transmission.…”

“…Third, climate change can also affect the seasonality of mortality, e.g. via increases in mortality in the summertime due to the increased frequency of heatwaves [16] or effects on pathogen life history [6].…”

El Niño Southern Oscillation (ENSO) and Health: An Overview for Climate and Health Researchers

“…Numerical schemes take the output from seasonal climate forecast models, usually in the form of a rainfall and/or temperature time series, and ingest this into numerical process-based disease models for diseases such as malaria and dengue (e.g., Liverpool Malaria Model, [99]). Typically the output from disease models includes disease parameters such as disease transmission, size of mosquito population, and disease incidence [100]. Statistical or empirically based forecasting schemes generally draw on a variety of statistical methods and use empirical observations of climate and disease incidence to construct transfer functions that statistically link climate disease associations.…”