Genetic epidemiology of the Alpine ibex reservoir of persistent and virulent brucellosis outbreak

Abstract

While it is now broadly accepted that inter-individual variation in the outcomes of host–pathogen interactions is at least partially genetically controlled, host immunogenetic characteristics are rarely investigated in wildlife epidemiological studies. Furthermore, most immunogenetic studies in the wild focused solely on the major histocompatibility complex (MHC) diversity despite it accounts for only a fraction of the genetic variation in pathogen resistance. Here, we investigated immunogenetic diversity of the Alpine ibex (Capra ibex) population of the Bargy massif, reservoir of a virulent outbreak of brucellosis. We analysed the polymorphism and associations with disease resistance of the MHC Class II Drb gene and several non-MHC genes (Toll-like receptor genes, Slc11A1) involved in the innate immune response to Brucella in domestic ungulates. We found a very low neutral genetic diversity and a unique MHC Drb haplotype in this population founded few decades ago from a small number of individuals. By contrast, other immunity-related genes have maintained polymorphism and some showed significant associations with the brucellosis infection status hence suggesting a predominant role of pathogen-mediated selection in their recent evolutionary trajectory. Our results highlight the need to monitor immunogenetic variation in wildlife epidemiological studies and to look beyond the MHC.

Genetic characterizations of Toll‐like receptors in the brown rat and their associations with pathogen infections

“…2018; Quéméré et al . 2020). The PCR was carried out in a 20 μL volume, containing 1 μL of cDNA, 10 μL 2 × Taq MasterMix (Dye) (CWBio, Beijng, China), 1 μL of corresponding primer (10 μM), and 7 μL sterilized water.…”

Selection Balancing at Innate Immune Genes: Adaptive Polymorphism Maintenance in Toll-Like Receptors

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Evolutionary pressures rendered by animal husbandry practices for avian influenza viruses to adapt to humans

“…This decrease in variation was also affected by positive selection to adapt to different ambient temperatures, which also affects the types of pathogens that will challenge these animals ( Stefanović et al., 2021 ). Very low genetic diversity and a unique MHC (Drb) haplotype in a population of Alpine ibex seem to be the cause of these animals’ susceptibility to brucellosis and their role as a reservoir for virulent outbreaks of this disease ( Quéméré et al., 2020 ).…”