Humidity – The overlooked variable in the thermal biology of mosquito‐borne disease

Abstract

Vector-borne parasites are common, important biological enemies of humans, animals and plants, transmitted by one living organism to another. Despite the recent gains in reducing the overall global burden for parasites like malaria (Ashepet et al., 2021;Bhatt et al., 2015;Gething et al., 2010), vector-borne diseases still account for 17% of all infectious diseases and cause 700,000 deaths in humans annually (WHO, 2020). Livestock and crop systems are also plagued by vector-borne diseases, which place serious constraints on agricultural production globally (Döring, 2017;Garros et al., 2017), and vector-borne diseases can be devastating in wildlife populations, particularly when introduced to new areas. Collectively, tens of billions of dollars are spent every year on control, medical interventions and mitigating loss of productivity (

Helminth ecological requirements shape the impact of climate change on the hazard of infection

“…Our findings bring a new perspective to the study of climate and infectious diseases by addressing the role of humidity, in addition to temperature, to helminth transmission. Despite the well recognized require ment of humidity for helminth life cycles (Beveridge et al, 1989;Pandey et al, 1993;Prasad, 1959), including vectors and their diseases (Berger et al, 2014;Brown et al, 2023), this variable is often neglected in favour of temperature, which is more frequently recorded in the field and easier to manipulate in the laboratory. We show that humidity is a key environmental vari able for understanding the climate driven dynamics of free living stages of stomach helminths.…”

Oviposition status and sugar availability influence measures of transmission potential in malaria-infected mosquitoes

“…In general, however, as these results suggest, the consequences of the interactions between physiological (nutrition) and evolutionary (egg retention) trade-offs in the vector are likely to be complex for parasite fitness. As such, this complexity further underscores the importance of quantifying the contribution of selective oviposition behavior to disease transmission [41, 65], especially since most integrated vector control strategies [1, 14, 15, 16, 17, 18, 19] and human-induced climate change either directly or indirectly target this key mosquito behavior [20, 21, 22, 23, 24].…”

“…First, integrated vector management strategies either directly or indirectly alter the availability of oviposition sites, by managing water sources for instance, to identifying specific physical, chemical, and biological cues underlying selective oviposition behavior for targeting with chemical or biological means [1, 14, 15, 16, 17, 18, 19]. Second, the availability of oviposition sites will continue to change as a cumulative response to climatic factors such as global warming and changes in rainfall patterns to the increasing urbanization and deforestation [20, 21, 22, 23, 24]. By altering the number and distribution of oviposition habitats, both scenarios could select for variation in oviposition behavior and thus modify parasite/disease transmission in the process.…”

Low humidity enhances Zika virus infection and dissemination inAedes aegyptimosquitoes

“…While most predictions about the impact of climate change on vector-borne disease transmission are focused on temperature, little is known about how other climate variables will impact vector-borne disease dynamics. A climate variable tightly linked to temperature is humidity [8]. Given the importance of dehydration in mosquito physiology [9, 10], the variability in humidity across environments, and the predicted changes in humidity under climate change, it is imperative that we also study the impact that it has on mosquito infection and transmission of arboviruses.…”