Biology subjects

Erbeck, K.

Publications and source records attributed to Erbeck, K..

3 recordsLinked to original sources

bioRxiv2024

SARS-CoV-2 within-host population expansion, diversification and adaptation in zoo tigers, lions and hyenas

SARS-CoV-2 rapidly adapts to new hosts following cross-species transmission; this is highly relevant as novel within-host variants have emerged following infection of susceptible wild and domestic animal species. Furthermore, SARS-CoV-2 transmission from animals (e.g., white-tailed deer, mink, domestic cats, and others) back to humans has also been observed, documenting the potential of novel animal-derived variants to infect humans. We investigated SARS-CoV-2 evolution and host-specific adaptation during an outbreak in Amur tigers (Panthera tigris altaica), African lions (Panthera leo), and spotted hyenas (Crocuta crocuta) at Denver Zoo in late 2021. SARS-CoV-2 genomes from longitudinal samples collected from 16 individuals were evaluated for within-host variation and genomic signatures of selection. The outbreak was likely initiated by a single spillover of a rare Delta sublineage subsequently transmitted from tigers to lions to hyenas. Within-host virus populations rapidly expanded and diversified. We detected signatures of purifying and positive selection, including strong positive selection in hyenas and in the nucleocapsid (N) gene in all animals. Four candidate species-specific adaptive mutations were identified: N A254V in lions and hyenas, and ORF1a E1724D, spike T274I, and N P326L in hyenas. These results reveal accelerated SARS-CoV-2 adaptation following host shifts in three non-domestic species in daily contact with humans.

evolutionary biology↗

bioRxiv2024

SARS-CoV-2 outbreak in lions, tigers and hyenas at Denver Zoo

In late 2019, SARS-CoV-2 spilled-over from an animal host into humans, where it efficiently spread, resulting in the COVID-19 pandemic. Through both natural and experimental infections, we learned that many animal species are susceptible to SARS-CoV-2. Importantly, animals in close proximity to humans, including companion, farmed, and those at zoos and aquariums, became infected, and many studies demonstrated transmission to/from humans in these settings. In this study, we first review the literature of SARS-CoV-2 infections in tigers and lions, and compare species, sex, age, virus and antibody detection assay, and types, frequency and length of clinical signs, demonstrating broad heterogeneity amongst infections. We then describe a SARS-CoV-2 outbreak in lions, tigers and hyenas at Denver Zoo in late 2021. Animals were tested for viral RNA (vRNA) for four months. Lions had significantly more viral RNA in nasal swabs than both tigers and hyenas, and many individual lions experienced viral recrudescence after weeks of undetectable vRNA. Infectious virus was correlated with high levels of vRNA and was more likely to be detected earlier during infection. Four months post-infection, all tested animals generated robust neutralizing antibody titers. Animals were infected with Delta lineage AY.20 identical to a variant circulating at less than 1% in Colorado humans at that time, suggesting a single spillover event from an infected human spread within and between species housed at the zoo. Better understanding of epidemiology and susceptibility of SARS-CoV-2 infections in animals is critical to limit the current and future spread and protect animal and human health. ImportanceSurveillance and experimental testing have shown many animal species, including companion, wildlife, and conservatory, are susceptible to SARS-CoV-2. Early in the COVID-19 pandemic, big cats at zoological institutions were among the first documented cases of naturally infected animals; however, challenges in the ability to collect longitudinal samples in zoo animals have limited our understanding of SARS-CoV-2 kinetics and clearance in these settings. We measured SARS-CoV-2 infections over three months in lions, tigers and hyenas at Denver Zoo, and detected viral RNA, infectious virus, neutralizing antibodies, and recrudescence after initial clearance. We found lions had longer and higher levels of virus compared to the other species. All animals were infected by a rare viral lineage circulating in the human population, suggesting a single spillover followed by interspecies transmission. These data are important in better understanding natural SARS-CoV-2 spillover, spread and infection kinetics within multiple species of zoo animals.

microbiology↗

bioRxiv2021

Feline leukemia virus (FeLV) endogenous and exogenous recombination events result in multiple FeLV-B subtypes during natural infection

Feline leukemia virus (FeLV) is associated with a range of clinical signs in felid species. The primary hosts of FeLV are domestic cats of the Felis genus that also harbor endogenous FeLV (enFeLV) elements stably integrated in their genomes. EnFeLV elements display 86% nucleotide identity to exogenous, horizontally transmitted FeLV (FeLV-A). Variation between enFeLV and FeLV-A is primarily in the long terminal repeat (LTR) and env regions, which potentiates generation of FeLV-B recombinant subtypes during natural infection with enhanced virulence. The aim of this study was to examine exogenous FeLV (exFeLV) and enFeLV recombination events in a natural FeLV epizootic. We previously described that of 32 individuals in a closed colony with productive FeLV-A infection, 22 had detectable circulating FeLV-B. We cloned and sequenced the env gene of FeLV-B, FeLV-A, and enFeLV spanning known recombination breakpoints, examining between 1-13 clones per individual to assess sequence diversity and recombination sites. We documented multiple recombination breakpoints resulting in the production of unique FeLV-B genotypes. At least half of the cats harbored more than one FeLV-B variant, and almost all animals had variants similar to those recovered from at least one other individual in the colony. This analysis reveals that FeLV-B is predominantly generated de novo within each host, though horizontal transmission may be inferred based upon FeLV-B sequence identities between individuals. This work represents a comprehensive analysis of endogenous-exogenous retroviral interactions with important insights into host-viral interactions that underlie disease pathogenesis in a natural setting. ImportanceFeline leukemia virus (FeLV) is a felid retrovirus associated with a variety of disease outcomes. Exogenous FeLV-A is the most common horizontally transmitted virus subgroup. Domestic cats (Felis catus) harbor endogenous copies of FeLV (enFeLV) in their genomes. Recombination between FeLV-A and enFeLV may result in emergence of largely replication-defective, but highly virulent recombinant strains. FeLV-B, the most common recombinant form, results when enFeLV env recombines with FeLV-A during FeLV replication. This study evaluated endogenous-exogenous recombination outcomes in a naturally-infected closed colony of domestic cats to determine recombination sites and FeLV-B genotypic heterogeneity associated with enhanced disease virulence. While FeLV-A and enFeLV genotypes were highly conserved, a large number of unique FeLV-B variants were identified in association with predicted recombination hotspots. The findings provide insight into recombination events between viral and host genomes that result in new, and potentially more pathogenic, viral strains.

microbiology↗