Boughton, R. | bioRxiv Science

bioRxiv2024

Torque Teno Sus Virus 1: A Potential Surrogate Pathogen to Study Pig-Transmitted Transboundary Animal Diseases

Understanding the epidemiology and transmission dynamics of transboundary animal diseases (TADs) among wild pigs (Sus scrofa) will aid in preventing the introduction or containment of TADs among wild populations. Given challenges associated with studying TADs in free-ranging populations, a surrogate pathogen system for in situ studies of pathogen dynamics would be ideal to elucidate how pathogens may circulate and be maintained within populations, how they may spillover into domestic populations, and how disease spread may be mitigated. We assessed the suitability of Torque teno sus virus 1 (TTSuV1) to serve as a surrogate pathogen for molecular epidemiological studies in wild pigs by investigating the prevalence, persistence, correlation with host health status and genetic variability at two study areas: Archbolds Buck Island Ranch in Florida and Savannah River Site in South Carolina. We then conducted a molecular epidemiological case study within the Archbolds Buck Island Ranch site to determine how analysis of this pathogen could inform transmission studies. Prevalence was high at both study areas (40%, n = 190). Phylogenetic analyses revealed high levels of genetic variability within and between study sites. Our case study showed that pairwise host relatedness and geographic distance were highly correlated to pairwise viral genetic similarity. Molecular epidemiological analyses revealed a distinct pattern of direct transmission from pig to pig occurring within and between family groups. Our results suggest TTSuV1 is highly suitable for molecular epidemiological analyses and will be useful for future in situ studies of transmission dynamics in wild pigs.

ecology↗

bioRxiv2023

Translocations spur population growth but exacerbate inbreeding in an imperiled species

Land and natural resource usage that supports human society can pose a risk to the survival of other species, spurring biodiversity loss. In extreme cases, when development threatens the existence of individuals, wildlife managers may perform mitigation translocations, relocating individuals out of harms way. We investigated the efficacy of mitigation translocations as a conservation strategy in Federally Threatened Florida Scrub-Jays using a dataset that provided unprecedented resolution into both the demographic and genomic outcomes of translocations. Over the course of seven years, a total of fourteen groups (51 jays) from five subpopulations that had been declining from agriculture and lack-of-fire driven habitat degradation were translocated to a larger site of more contiguous restored habitat with only four family groups, to mitigate for loss of these subpopulations from mining activity. Habitat restoration and translocations established a core population that increased 10-fold in size after only 17 years from the first translocations. Pedigree analyses of this population revealed that a small subset of mostly translocated individuals fueled the demographic expansion, with a single breeding pair responsible for [~]24% of the ancestral genetic contributions since 2008. Genomic comparisons between translocated individuals and individuals from the core population before and after translocations revealed that the high reproductive skew led to increased inbreeding and loss of genetic diversity. This study stresses the importance of demographic and genetic monitoring following translocations, and that subsequent, genetic-rescue-oriented translocations may be necessary in mitigation scenarios to counter the genetic consequences of reproductive skew in fragmented populations. Significance StatementThere is ongoing debate surrounding the effectiveness of mitigation-driven translocations for conservation, however we show that translocations to mitigate the effects of mining on Federally Threatened Florida Scrub-Jays spurred population growth; a major boon to the viability of this species. We translocated individuals from at-risk subpopulations that were demographic sinks into recently restored habitat, which quickly established a rapidly growing core population. We demonstrate that demographic and genetic recovery do not necessarily go hand-in-hand, as reproduction was highly skewed towards a small subset of mostly translocated individuals, which increased inbreeding and eroded genetic diversity. This stresses the importance of demographic and genetic monitoring for identifying reproductive skew, allowing for adaptive management that addresses inbreeding and achieves broader conservation goals.

evolutionary biology↗