Host competence, interspecific competition and vector preference interact to determine the vector-borne infection ecology

Abstract

Understanding how ecological interactions affect vector-borne disease dynamics is crucial in the context of rapid biodiversity loss and increased emerging vector-borne diseases. Although there have been many studies on the impact of interspecific competition and host competence on disease dynamics, few of them have addressed the case of a vector-borne disease. Using a simple compartment model with two competing host species and one vector, we investigated the combined effects of vector preference, host competence, and interspecific competition on disease risk in a vector-borne system. Our research demonstrated that disease transmission dynamics in multi-host communities are more complex than anticipated. Vector preference and differences in host competence shifted the direction of the effect of competition on community disease risk, yet interspecific competition quantitatively but not qualitatively changed the effect of vector preference on disease risk. Our work also identified the conditions of the dilution effect and amplification effect in frequency-dependent transmission mode, and we discovered that adding vector preference and interspecific competition into a simple two-host-one-vector model altered the outcomes of how increasing species richness affects disease risk. Our work explains some of the variation in outcomes in previous empirical and theoretical studies on the dilution effect.

Towards a Generic Agent Based Vector-Host Model

“…This model complements studies e.g. [44,45,46] by incorporating temperaturedependent vector developmental stages, host-vector interactions, and the influence of host movement on tick species characterized by passive host-seeking behaviour, exemplified by Ixodes ricinus. Our model's uniqueness lies in its ability to encompass the entire tick life cycle, representing development as a temperature-dependent process and the sole interaction between vector and host through blood meals.…”

Effects of cattle on vector-borne disease risk to humans: A systematic review

“…An amplifying host is an organism in which an infectious agent (such as a virus or bacterium) that is pathogenic for some other species is able to replicate rapidly and to high concentrations (97) as evidenced in the case of Japanese encephalitis virus for which pigs are the amplifying host species (98). The ability to obtain and transmit pathogens to other organisms refers to the competence of the host in transmitting that infection (99).…”

Mixed-species assemblages and disease: the importance of differential vector and parasite attraction in transmission dynamics

“…Given conservation and public health threats from emerging and zoonotic vector-borne pathogens, this warrants future exploration. Additionally, because host competence, tolerance and avoidance behaviours can greatly influence disease dynamics, especially when paired with vector or parasite bias for certain host-types [62], incorporation of interspecific variation in host ecological and epidemiological features into our model could be important for predicting and managing zoonotic risk. As disease control strategies often focus on a single or few hosts that play comparatively large roles in amplifying pathogen transmission [91], these could include highly competent hosts that are attractive to vectors within an assemblage.…”

“…Mathematical models demonstrate that disparities among host types in attack rates, such as those described above, can strongly affect community-level disease dynamics. In cases where hosts vary in competence, amplification generally results from attack biases toward more competent hosts, and dilution from biases toward less competent hosts [60][61][62]. While models often assume that vector and parasite biases are static, these biases and their effects on disease dynamics can change.…”