À la carte: how mosquitoes choose their blood meals

Abstract

Mosquitoes are important vectors for human diseases, transmitting pathogens that cause a range of parasitic and viral infections. Mosquito blood-feeding is heterogeneous, meaning that some human hosts are at higher risk of receiving bites than others, and this heterogeneity is multifactorial. Mosquitoes integrate specific cues to locate their hosts, and mosquito attraction differs considerably between individual human hosts. Heterogeneous mosquito biting results from variations in both host attractiveness and availability and can impact transmission of vector-borne diseases. However, the extent and drivers of this heterogeneity and its importance for pathogen transmission remain incompletely understood. Here, we review methods and recent data describing human characteristics that affect host-seeking behavior and host preferences of mosquito disease vectors, and the implications for vector-borne disease transmission.

Keywords: biting heterogeneity; host attraction; mosquito behavior; pathogen transmission.

Figure 1.. Graphic overview of host-related cues involved in mosquito host localization.

As a mosquito approaches a host (proximity to host increases), the number of host-related cues and the differences in such cues between individual hosts increases. The arrows and symbols indicate previously observed synergistic effects between host-related cues [, , –19]. The factors depicted here may interact to dictate host attractiveness and, together with host availability, relate to successful mosquito feeding.

Figure 2.. Mosquito feeding success based on host age and gender determined by STR genotyping.

Right: proportion of nightly bites by age and gender of study participants using bloodmeals from indoor caught mosquitoes from Burkina Faso [31], Kenya [28], and Malawi [26], and from barrier-screen caught mosquitoes from Papua New Guinea [23]. Left: proportion of nightly bites across all sites, separated by age and gender. Age category is represented by color and gender is represented by shade. Size of pie chart segments represent the number of bites per night at risk for a given category.

Figure I.. Application of forensic weight-of-evidence likelihood models to mosquito bloodmeal identification using bistro R package.

Left: mosquitoes that have taken bloodmeals from Person 1 (blue), Person 2 (red), or both. Middle: Corresponding simulated STR profiles at 3 representative loci for each bloodmeal. STR profiles simulated from peak heights provided in the ProvedIt dataset for samples and mixtures containing DNA from individuals RD14–0003-31 and RD14–0003-32 [110, 111]. Peak heights are normalized to the highest peak across all samples. Right: normalized log10 likelihood ratios (log10LR) for all people in the ProvedIt dataset, generated using the bistro R package [110]. Normalized log10LR values are highlighted for Person 1 (blue) and Person 2 (red), and matches determined by the bistro algorithm are highlighted with squares.