The synzootic potential of common epidemics in chamois populations

Abstract

Southern chamois (Rupicapra pyrenaica) is a medium-sized and gregarious mountain ungulate with populations affected by periodic outbreaks of border disease virus (BD), infectious keratoconjunctivitis (IKC), and sarcoptic mange (SM). Even though the impact of each disease on chamois populations has been described in detail, there is a lack of information about the potential impact of concomitant epidemics and the synzootic potential (co-occurring enzootic or epizootic processes producing worse health outcomes in wildlife) on chamois populations. Furthermore, whether a specific order of apparition of epidemics is more or less harmful for the host population is practically unknown not only for chamois but also for most mammal populations. Using a population viability analysis (PVA), we studied the consequences of multiple disease outbreaks with synzootic potential on growth rates and probabilities of extinction of virtual populations exposed to hard winters, density dependence, and co-occurring BD, IKC, and SM outbreaks. Such infections are not under cross-immunity nor density-dependent processes and thus are supposed to affect population demography independently. Heavy snowfalls are also likely to occur in our simulated populations. Our simulations showed that a second outbreak, even caused by a low virulent pathogen, causes an increase in the probability of extinction of the host population with regard to the first outbreak. IKC-BD- and SM-BD-affected populations had a higher risk of becoming extinct in 50 years confirming the extra risk of multiple outbreaks on the viability of the affected populations.

Overcoming the limitations of wildlife disease monitoring

“…By merging both HCM and WHM, IWM allows a comprehensive understanding of role of each species in pathogen transmission and maintenance, transmission routes, and disease status in a system (Fenton and Pedersen, 2005;Pepin et al, 2017;Gortázar et al, 2021), requiring collaboration among health, wildlife, and livestock authorities and managers. Furthermore, achieving knowledge of the host community assemblage allows identifying the drivers of epidemiology and infection within the system (Martínez-López et al, 2009;Barasona et al, 2019;Triguero-Ocaña et al, 2020;Barroso et al, 2023), and monitoring the host network community and the population structure of the indicator host species provide additional early indicators of trends and changes in disease and mortality through network imbalances before the pathogen crosses the interspecies barrier (Craft, 2015;Espinaze et al, 2018;Garrido-Amaro et al, 2023).…”