The importance of temperature fluctuations in understanding mosquito population dynamics and malaria risk

Abstract

Temperature is a key environmental driver of Anopheles mosquito population dynamics; understanding its central role is important for these malaria vectors. Mosquito population responses to temperature fluctuations, though important across the life history, are poorly understood at a population level. We used stage-structured, temperature-dependent delay-differential equations to conduct a detailed exploration of the impacts of diurnal and annual temperature fluctuations on mosquito population dynamics. The model allows exploration of temperature-driven temporal changes in adult age structure, giving insights into the population’s capacity to vector malaria parasites. Because of temperature-dependent shifts in age structure, the abundance of potentially infectious mosquitoes varies temporally, and does not necessarily mirror the dynamics of the total adult population. In addition to conducting the first comprehensive theoretical exploration of fluctuating temperatures on mosquito population dynamics, we analysed observed temperatures at four locations in Africa covering a range of environmental conditions. We found both temperature and precipitation are needed to explain the observed malaria season in these locations, enhancing our understanding of the drivers of malaria seasonality and how temporal disease risk may shift in response to temperature changes. This approach, tracking both mosquito abundance and age structure, may be a powerful tool for understanding current and future malaria risk.

Weather-driven malaria transmission model with gonotrophic and sporogonic cycles

“…Furthermore, most of the aforementioned modelling studies used constant or mean monthly temperature in their formulation. Recent studies have shown that the incorporation of daily (diurnal) temperature fluctuations in the model may also affect predictions [12,13,74].…”

Partitioning the influence of ecology across scales on parasite evolution

“…Exposed vectors are recruited into the infectious class according to Although can be formulated to fluctuate with diurnal and seasonal temperature variation (Beck‐Johnson et al. , ), we assume constant temperatures so that is constant. The fraction of exposed mosquitoes surviving long enough to become infectious is given by the exponential term in equation .…”

“…) in response to seasonal changes in temperature and rainfall (Beck‐Johnson et al. , reviewed in Eikenberry and Gumel ). Further, interventions aimed at mosquitoes (e.g., insecticide treated nets) are widespread and have contributed to substantial declines in malaria infections (Bhatt et al.…”

Meteorological Parameters and Mosquito Abundance in Pashan Area of Pune, India during South West Monsoon and Post-Monsoon Seasons in 2016

“…Impacts of temperature on population dynamics and vector competence are complex (Beck-Johnson et al, 2013). Mosquitoes are sensitive to temperature throughout their life cycle and it has been shown by mathematical modeling studies that the fluctuations in diurnal temperatures may affect the mosquito life cycle and malaria transmission (Beck-Johnson et al, 2017). Carrington et al, in a study conducted in northwest Thailand have found that large diurnal temperature range (DTR) adversely affects mosquito biology by extending immature development phase, lowered larval survival and reduced female reproductive capacity (Carrington et al, 2013a).…”