Research effort on birds’ reservoir host potential for Lyme borreliosis: A systematic review and perspectives

Abstract

Zoonotic tick‐borne diseases threat human and animal health. Understanding the role of hosts in the production of infected ticks in an epidemiological system is essential to be able to design effective measures to reduce the exposure of humans and animals to infectious tick bites. The reservoir host potential, that is, number of infected ticks produced by a host species, depends on three components: tick production, realized reservoir competence and host density. The parameters and factors that determine the reservoir host potential need to be characterized to achieve a robust understanding of the dynamics of pathogen–tick–host systems, and thus to mitigate the acarological risk of emerging infections. Few studies have investigated the role of birds in the local spread of Lyme borreliosis Borrelia. Knowledge of the research effort on the reservoir host potential of birds in Lyme borreliosis Borrelia circulation is necessary to prioritize future research on this topic. We provide a systematic review of the research effort on components of the reservoir host potential of wild birds for Lyme borreliosis Borrelia circulation, and factors that modulate these components in the European epidemiological system. Our review of 242 selected publications showed that tick production has been 1.4 and 21 times more studied than realized reservoir competence and bird density respectively. Only one study achieved to characterize the global host reservoir potential of birds in a given epidemiological system. Investigated factors were mostly related to bird species identity, individual characteristics of birds and tick characteristics, whereas the influence of bird life‐history traits have been largely under‐investigated. Because simultaneous characterization of all parameters is notoriously complex, interdisciplinary research is needed to combine and accumulate independent field and laboratory investigations targeting each parameter on specific epidemiological system or host species. This can help gain an integrated appraisal of the functioning of the studied system at a local scale.

Host adaptation drives genetic diversity in a vector-borne disease system

“…Further, we found that individual bird infection communities were characterized by greater genotype co-occurrence, indicating facilitation, in contrast with mammal communities that appear to exhibit only competitive interactions among genotypes. These findings may be partially explained by birds' longer lifespan, different immunity mechanisms, larger home ranges, or other life-history traits resulting in more opportunities for infection (Rataud et al 2021). Thus, our study emphasizes the role of passerine birds in maintaining Bb transmission and increasing human disease risk locally, in addition to their known roles as reservoir hosts and tick dispersers (Ginsberg et al 2006;Brinkerhoff et al 2010Brinkerhoff et al , 2011Vuong et al 2014;Loss et al 2016;Becker & Han 2021).…”

“…Further, we found that individual bird infection communities were characterized by greater genotype co-occurrence, indicating facilitation, in contrast with mammal communities that appear to exhibit only competitive interactions among genotypes. These findings may be partially explained by birds’ longer lifespan, different immunity mechanisms, larger home ranges, or other life-history traits resulting in more opportunities for infection (Rataud et al . 2021).…”

Host adaptation drives genetic diversity in a vector-borne disease system

“…Further, individual bird infection communities were characterized by greater genotype co-occurrence, indicating facilitation, in contrast with mammal communities that appear to exhibit only competitive interactions among genotypes. These findings may be partially explained by birds' longer lifespans, different immunity mechanisms, larger home ranges, or other life-history traits resulting in more opportunities for infection ( 76 ). Thus, our study emphasizes the role of passerine birds in maintaining Bb transmission and increasing human disease risk locally, in addition to their known roles as reservoir hosts and tick dispersers ( 18 , 45 , 74 , 77–79 ).…”

Detection of Pathogens and Ticks on Sedentary and Migratory Birds in Two Corsican Wetlands (France, Mediterranean Area)

“…Hard ticks (Ixodidae) are vectors of several pathogens, such as Rickettsia spp., Borrelia spp., and Crimean-Congo Hemorrhagic Fever virus (CCHFV) [50][51][52]. In Europe and the Mediterranean, most ticks found on avian species are immature stages from the genus Hyalomma, Ixodes ticks of all stages and, sporadically, immature stages from the genera Haemaphysalis and Rhipicephalus [52,53].…”