Vector diversity and malaria prevalence: global trends and local determinants

Abstract

Identifying determinants of global infectious disease burden is a central goal of disease ecology. While it is widely accepted that host diversity structures parasite diversity and prevalence across large spatial scales, the influence of vector diversity on disease risk has rarely been examined despite the role of vectors as obligatory intermediate hosts for many parasites. Malaria, for instance, can be transmitted by over 70 species of mosquitoes, but the impact of this diversity on malaria risk remains unclear. Further, such relationships are likely dependent on the context in which disease transmission occurs, as arthropod life history and behavior are highly sensitive to environmental factors such as temperature. We studied the relationship between vector diversity, malaria prevalence, and environmental attributes using a unique dataset we curated by integrating several open-access sources. Globally, the association between vector species richness and malaria prevalence differed by latitude, indicating that this relationship is strongly dependent on underlying environmental conditions. Structural equation models further revealed different processes by which the environment impacts vector community assemblage and function, and subsequently disease prevalence, in different regions. In Africa, the environment exerted a top-down influence on disease through its role in shaping vector communities, whereas in Southeast Asia, disease prevalence is influenced by more complex interactions between the physical and socioeconomic environment (i.e., rainfall and GDP) and vector diversity across sites. This work highlights the key role of vector diversity in structuring disease distribution at large spatial scales and offers crucial insights to vector management and disease control.

Impact of vector richness on the risk of vector‐borne disease: The role of vector competence

“…A central goal in disease ecology is to identify the factors that drives the spread diseases. Vectors are important intermediate hosts for many parasites and greatly impact parasite transmission (Hoi et al, 2022), yet the role of vector richness and vector competence in moderating the diversity-disease relationship has received little attention. Based on the theoretical model of Takimoto et al (2022), we examined how the combined effect of vector richness, vector competence, and vector interspecific interactions impact disease risk in a multi-vector community.…”

“…In fact, many vectorborne diseases are transmitted between hosts via multiple vectors. For instance, malaria has more than four mosquito vectors (Hoi et al, 2020(Hoi et al, , 2022, West Nile virus has 7-16 mosquito vectors (Roche et al, 2013), and Chagas disease has up to 10 triatomine vectors (Eduardo et al, 2018). Although vector richness may strongly influence the pathogen transmission (Brooks & Zhang, 2010), the effect of vector richness on disease risk is poorly understood.…”

Limited impact of within-vector ecology on the evolution of malaria parasite transmission investment

“…This raises the interesting possibility that parasites in diverse communities may have to be plastic or tune their strategies to the particularities of each community (Sibly, 1996). In different parts of the world where the diversity and seasonality of vector communities are drastically different from one another (Carter and Mendis, 2002;Baird, 2017;Hoi et al, 2022), vector diversity, especially that of seasonally varying community composition, may be an important driver of parasite local adaption.…”

DataSheet_1.docx

“…This raises the interesting possibility that parasites in diverse communities may have to be plastic or tune their strategies to the particularities of each community (Sibly, 1996). In different parts of the world where the diversity and seasonality of vector communities are drastically different from one another (Carter and Mendis, 2002;Baird, 2017;Hoi et al, 2022), vector diversity, especially that of seasonally varying community composition, may be an important driver of parasite local adaption.…”