The macroecology and evolution of avian competence for Borrelia burgdorferi

Abstract

Aim Prediction of novel reservoirs of zoonotic pathogens would be improved by the identification of interspecific drivers of host competence (i.e., the ability to transmit pathogens to new hosts or vectors). Tick‐borne pathogens can provide a useful model system, because larvae become infected only when feeding on a competent host during their first blood meal. For tick‐borne diseases, competence has been studied best for Borrelia burgdorferi sensu lato (Bbsl), which causes Lyme borreliosis. Major reservoirs include several small mammal species, but birds might play an under‐recognized role in human risk given their ability to disperse infected ticks across large spatial scales. Here, we provide a global synthesis of the ecological and evolutionary factors that determine the ability of bird species to infect larval ticks with Bbsl. Location Global. Time period 1983–2019. Major taxa studied Birds. Methods We compiled a dataset of Bbsl competence across 183 bird species and applied meta‐analysis, phylogenetic factorization and boosted regression trees to describe spatial and temporal patterns in competence, characterize its phylogenetic distribution across birds, reconstruct its evolution and evaluate the trait profiles associated with competent avian species. Results Half of the sampled bird species show evidence of competence for Bbsl. Competence displays moderate phylogenetic signal, has evolved multiple times across bird species and is pronounced in the genus Turdus. Trait‐based analyses distinguished competent birds with 80% accuracy and showed that such species have low baseline corticosterone, exist on both ends of the pace‐of‐life continuum, breed and winter at high latitudes and have broad migratory movements into their breeding range. We used these trait profiles to predict various likely but unsampled competent species, including novel concentrations of avian reservoirs within the Neotropics. Main conclusion Our results can generate new hypotheses for how birds contribute to the dynamics of tick‐borne pathogens and help to prioritize surveillance of likely but unsampled competent birds. Our findings also emphasize that birds display under‐recognized variation in their contributions to enzootic cycles of Bbsl and the broader need to consider competence in ecological and predictive studies of multi‐host pathogens.

Optimising predictive models to prioritise viral discovery in zoonotic reservoirs

“… 6 For example, machine learning approaches have generated candidate lists of probable, but unsampled, primate reservoirs of Zika virus, bat reservoirs of filoviruses, and avian reservoirs of Borrelia burgdorferi . 7 , 8 , 9 …”

Cellular and immunological mechanisms influence host-adapted phenotypes in a vector-borne microparasite

“…Given the importance to human health, recent reviews and meta-analyses have sought to identify host- and pathogen-derived traits contributing to potential zoonotic emergence. Host-associated traits included life-history traits [5–7], relationships among hosts [8], species interaction dynamics (e.g. domestication) [9–11] and phylogenetic relationships [12,13].…”

“…To understand the role of intraspecific Bb variation in host competence and assess the plausibility of MNP as a driver of Bb diversification, we experimentally evaluated the interaction between two reservoir vertebrate hosts and three genotypically distinct Bb strains. Hosts were rodents (white-footed mice, Peromyscus leucopus ) and birds (American robins, Turdus migratorius ) that are competent for Bb and frequently infected in nature [5]. We aimed to address the following questions: (i) do Bb strains with distinct ospC genotypes exhibit variation in fitness (transmission to ticks) across two representative host species?…”

The effect of host community functional traits on plant disease risk varies along an elevational gradient

“…The functional traits expressed by those species that are able to colonize and persist in a given location can, in turn, affect disease risk Johnson et al, 2013;Kirk et al, 2019). Specifically, an infected host's ability to transmit disease to uninfected hosts, a trait often referred to as host competence, is often related to fast-growing, poorly defended tissues and short lifespans (Becker and Han, 2021;Cronin et al, 2014Cronin et al, , 2010Huang et al, 2013;Johnson et al, 2012;Martin et al, 2019Martin et al, , 2016Parker and Gilbert, 2018;Stewart Merrill and Johnson, 2020;Welsh et al, 2020). Importantly, these functional trait values also underlie ecological tradeoffs related to host growth and defense, resource acquisition and allocation, and survival and reproduction (i.e., life history) (Coley et al, 1985;Herms and Mattson, 1992;Martin et al, 2016;Reich, 2014;Reich et al, 2003;Ricklefs and Wikelski, 2002;Stearns, 1992Stearns, , 1989Wright et al, 2004).…”