Human–Mosquito Contact: A Missing Link in Our Understanding of Mosquito-Borne Disease Transmission Dynamics

Abstract

Despite the critical role that contact between hosts and vectors, through vector bites, plays in driving vector-borne disease (VBD) transmission, transmission risk is primarily studied through the lens of vector density and overlooks host–vector contact dynamics. This review article synthesizes current knowledge of host–vector contact with an emphasis on mosquito bites. It provides a framework including biological and mathematical definitions of host–mosquito contact rate, blood-feeding rate, and per capita biting rates. We describe how contact rates vary and how this variation is influenced by mosquito and vertebrate factors. Our framework challenges a classic assumption that mosquitoes bite at a fixed rate determined by the duration of their gonotrophic cycle. We explore alternative ecological assumptions based on the functional response, blood index, forage ratio, and ideal free distribution within a mechanistic host–vector contact model. We highlight that host–vector contact is a critical parameter that integrates many factors driving disease transmission. A renewed focus on contact dynamics between hosts and vectors will contribute new insights into the mechanisms behind VBD spread and emergence that are sorely lacking. Given the framework for including contact rates as an explicit component of mathematical models of VBD, as well as different methods to study contact rates empirically to move the field forward, researchers should explicitly test contact rate models with empirical studies. Such integrative studies promise to enhance understanding of extrinsic and intrinsic factors affecting host–vector contact rates and thus are critical to understand both the mechanisms driving VBD emergence and guiding their prevention and control.

Superinfection plays an important role in the acquisition of complexPlasmodium falciparuminfections among femaleAnophelesmosquitoes

“…This setup allows, with relatively low probabilities, for mosquitoes to feed on humans multiple days in a row to complete a single blood meal. This is supported by evidence of female Anopheles mosquitoes imbibing multiple blood meals per gonotrophic cycle 35,36 . This simulation also allows for the possibility that a mosquito may not feed on a human, which can occur if the mosquito feeds on other animals or does not successfully find a host.…”

Spatial Dynamics of Malaria Transmission

“…Blood Feeding With a well-defined population denominator, we can compute the frequency of blood feeding rates and the human fraction (i.e., the fraction of human blood meals among all blood meals) in each patch in response to the availability of humans and other available vertebrate hosts. To do so, we use functional responses to model blood feeding rates and habits [33][34][35][36].…”

“…e ., the fraction of human blood meals among all blood meals) in each patch in response to the availability of humans and other available vertebrate hosts. To do so, we use functional responses to model blood feeding rates and habits [33–36].…”

“…Adding spatial complexity to the model means the daily emigration rate (σ), mosquito dispersal (K), distribution of habitats (N ) and the distribution of eggs among patches (U) are additional parameters which define how populations may interact in space. While our analysis has focused on steady states, the models were formulated with parameters that can vary over time in response to changing availability of resources [33][34][35][36].…”

Aedes albopictus host odor preference does not drive observed variation in feeding patterns across field populations

“…Host preference plays a role in host contact rates, interacting with external factors, such as host availability, to influence feeding patterns in the field 1,4,5 . Feeding patterns, in turn, influence the probability of mosquito contact with infectious host reservoirs and onward transmission to susceptible hosts 6,7 .Despite the important role of host preference in pathogen transmission, this trait is not well characterized for the tiger mosquito, Aedes albopictus, a highly invasive nuisance species with the potential to transmit over twenty pathogens that infect a range of vertebrate host species 8,9 . Several of these pathogens share another mosquito vector, Ae.…”