Sinus tumors of Rocky Mountain bighorn sheep: investigation of an infectious etiology

2013 Spring.Includes bibliographical references.Rocky Mountain bighorn sheep are an icon in Colorado. As our state animal, bighorn sheep are a well-recognized symbol of the wildlife, wildlands, and wilderness-centric people that Colorado is famous for. Efforts to manage and conserve this species are a priority in Colorado and throughout western North America. As part of those efforts a great deal of research has been conducted to understand bighorn sheep respiratory disease, the leading infectious cause of death in these animals. In the process of investigating respiratory disease in bighorn sheep in Colorado, we discovered a surprisingly high occurrence of sinus tumors within the upper respiratory tracts of many animals. This disease had not been described previously and became the focus of work for this dissertation. Here, I have compiled our findings regarding the characterization of bighorn sheep sinus tumors and the results of our efforts to identify an infectious etiology for this disease. Through the examination of naturally-occurring cases, we identified characteristic histologic and gross features of bighorn sheep sinus tumors to define this disease. We also analyzed factors associated with sinus tumors at a population level. The results of this study suggest that bighorn sheep sinus tumors are an infectious disease, maintained within specific geographic areas corresponding to distinct populations of animals. Our results also suggest a role for bighorn sheep sinus tumors in predisposing animals to secondary infections by bacterial agents that can cause pneumonia. To specifically test the hypothesis that bighorn sheep sinus tumors are a transmissible disease, we experimentally inoculated bighorn sheep and domestic sheep lambs with a cell-free filtrate derived from a naturally-occurring bighorn sheep sinus tumor and its associated exudates. Within 18 months post-inoculation we demonstrated transmission of the disease to both bighorn sheep and domestic sheep species, supporting our hypothesis that bighorn sheep sinus tumors represent an infectious process. This experiment also provided an opportunity to examine tumors early in development, further characterize the cells comprising the tumors, and suggest mechanisms for pathogenesis. With evidence that bighorn sheep sinus tumors are caused by an infectious agent, we also attempted to identify a specific etiology for this disease. We primarily used PCR methods with degenerate PCR primers to evaluate samples from bighorn sheep sinus lining tissues for the presence of herpesviruses and retroviruses, which are well-known causes of infectious tumors. We successfully identified the presence of herpesviral and (likely endogenous) retroviral sequences in our samples, but we were unable to find an association between these viruses and the occurrence of sinus tumors. Based on similarities between bighorn sheep sinus tumors and oncogenic retroviral diseases of domestic sheep and goats, we specifically screened our samples for the presence of Jaagsiekte sheep retrovirus (JSRV), and enzootic nasal tumor viruses (ENTV-1 and ENTV-2). We successfully identified ENTV-2-specific sequences from some of our samples, but an association between this virus and bighorn sheep sinus tumors was not clear. We found an association between ENTV-2 and early tumor cases, but not well-defined tumors. While our PCR data alone did not definitively identify ENTV-2 as the cause of bighorn sheep sinus tumors, our histologic, histochemical, and immunohistochemical results have helped us to develop a hypothesis for the pathogenesis of bighorn sheep sinus tumors, and provided additional support for the hypothesis that this disease is caused by ENTV-2. Our working hypothesis for the pathogenesis of bighorn sheep sinus tumors is that epithelial cells of the sinus lining are infected by ENTV-2, but that uninfected periosteal pluripotent cells are stimulated to replicate, resulting in predominantly stromal tumors. This hypothesis is based on histologic observations, histochemical stains used to differentiate cell types, and IHC results specifically identifying the presence of ENTV antigen within surface epithelial cells of experimentally-induced tumors, but not within the predominating stromal cells of the tumors. These results help to explain why detection of the virus is uncommon in well-developed stromal tumors, but more easily detected in early tumor cases with less stromal proliferation. Additional research will help to further elucidate the pathogenesis of bighorn sheep sinus tumors, and the potential role that tumors may play in predisposing bighorn sheep to fatal respiratory disease. The definitive identification of an etiologic agent for bighorn sheep sinus tumors, and the development of an antemortem diagnostic assay will greatly enhance efforts to understand and manage this disease

Fluorescent visualization of a spreading surfactant

The spreading of surfactants on thin films is an industrially and medically important phenomenon, but the dynamics are highly nonlinear and visualization of the surfactant dynamics has been a long-standing experimental challenge. We perform the first quantitative, spatiotemporally-resolved measurements of the spreading of an insoluble surfactant on a thin fluid layer. During the spreading process, we directly observe both the radial height profile of the spreading droplet and the spatial distribution of the fluorescently-tagged surfactant. We find that the leading edge of spreading circular layer of surfactant forms a Marangoni ridge in the underlying fluid, with a trough trailing the ridge as expected. However, several novel features are observed using the fluorescence technique, including a peak in the surfactant concentration which trails the leading edge, and a flat, monolayer-scale spreading film which differs from concentration profiles predicted by current models. Both the Marangoni ridge and surfactant leading edge can be described to spread as $R \propto t^{\delta}$. We find spreading exponents, $\delta_H \approx 0.30$ and $\delta_\Gamma \approx 0.22$ for the ridge peak and surfactant leading edge, respectively, which are in good agreement with theoretical predictions of $\delta = 1/4$. In addition, we observe that the surfactant leading edge initially leads the peak of the Marangoni ridge, with the peak later catching up to the leading edge

Effects of Early Psychosocial Deprivation on the Development of Memory and Executive Function

This study investigated the effects of early institutional care on memory and executive functioning. Subjects were participants in the Bucharest Early Intervention Project (BEIP) and included institutionalized children, children with a history of institutionalization who were assigned to a foster care intervention, and community children in Bucharest, Romania. Memory and executive functioning were assessed at the age of 8 years using the Cambridge Neuropsychological Test and Automated Battery (CANTAB). As expected, children with a history of early institutional care performed worse on measures of both visual memory and executive functioning compared to their peers without a history of institutional care. In comparing children randomly assigned to the foster care intervention with their peers who had continued care in the institution, initial comparisons did not show significant differences on any of the memory or executive functioning outcomes. However, for one of the measures of executive functioning, after controlling for birth weight, head circumference, and duration of time spent in early institutional care, the foster care intervention was a significant predictor of scores. These results support and extend previous findings of deficits in memory and executive functioning among school-age children with a history of early deprivation due to institutional care. This study has implications for the millions of children who continue to experience the psychosocial deprivation associated with early institutional care

Tree Biomass and Carbon Storage in an Old Growth Forest in Southeastern Ohio

Recently there has been increased interest in determining the baseline levels of carbon storage in different ecosystems, because of greater concern over the issue of global climate change and increased atmospheric CO2 concentrations. With a better understanding of carbon sequestration in various ecosystems, we can use land in a more environment-conscious way, and negative human impacts on the earth can be decreased. Forest ecosystems are especially important, because they have an immense capacity to store carbon as compared to other ecosystems. The majority of carbon sequestered in forest ecosystems is contained in tree biomass, but there is also carbon contained in soil, leaf litter, and necromass. The primary objective of our experiment was to determine and compare the baseline amount of carbon sequestered in the biomass of different forest plots: old-growth versus young-growth and north-facing versus south-facing. We also compared these results to data that had been collected from the same plots in 2003. We found that for the most part, the amount of biomass had decreased; the only exception was the north-facing young-growth stand. This forest plot contained the most biomass, followed by the old-growth south-facing, then the young-growth south-facing, then the old-growth north-facing. We believe that the reason for the overall decrease in biomass was a large number of fallen trees

EVIDENCE OF TWO COCIRCULATING CANINE DISTEMPER VIRUS STRAINS IN MESOCARNIVORES FROM NORTHERN COLORADO, USA

Canine distemper virus (CDV) is a highly contagious pathogen that principally infects wildlife and domestic carnivores. Peridomestic species such as raccoons (Procyon lotor) experience outbreaks with high mortality. Clinical signs of infection include anorexia, fever, respiratory infection, and neurologic complications. Although not zoonotic, CDV poses a high risk to unvaccinated domestic animals and the conservation of endangered species. During 2013–16, we opportunistically collected wild and domestic carnivore specimens through a rabies surveillance program in northern Colorado, US. Brainstem and cerebellar tissue samples were independently tested for rabies and CDV by fluorescent antibody test. We tested a total of 478 animals for CDV, comprised of 10 wild and domestic carnivore species. A total of 15% (72/478) of all animals sampled tested positive for CDV, consisting of 24% (71/300) of raccoons and 4% (1/26) of coyotes (Canis latrans), but coinfection with rabies virus was not observed among CDV-positive animals. We extracted RNA from positive tissues, and a reverse-transcription PCR was used to create complementary DNA. We amplified and sequenced the hemagglutinin gene from 60 CDV-positive tissues, and a median joining network and maximum likelihood phylogenetic tree revealed two major lineages among samples. Phylogenetic analysis indicated that our sequences were most similar to the America-2 (n=55) and the America-3 (n=5) CDV lineages circulating in North America. Our results indicated two distinct and distantly related clades of CDV overlapping geographically and temporally among raccoon populations in northern Colorado

Experimental Infection of Brazilian Free-Tailed Bats (\u3ci\u3eTadarida brasiliensis\u3c/i\u3e) with Two Strains of SARS-CoV-2

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is presumed to have originated from wildlife and shares homology with other bat coronaviruses. Determining the susceptibility of North American bat species to SARS-CoV-2 is of utmost importance for making decisions regarding wildlife management, public health, and conservation. In this study, Brazilian free-tailed bats (Tadarida brasiliensis) were experimentally infected with two strains of SARS-CoV-2 (parental WA01 and Delta variant), evaluated for clinical disease, sampled for viral shedding and antibody production, and analyzed for pathology. None of the bats (n = 18) developed clinical disease associated with infection, shed infectious virus, or developed histopathological lesions associated with SARS-CoV-2 infection. All bats had low levels of viral RNA in oral swabs, six bats had low levels of viral RNA present in the lungs during acute infection, and one of the four bats that were maintained until 28 days post-infection developed a neutralizing antibody response. These findings suggest that Brazilian free-tailed bats are permissive to infection by SARS-CoV-2, but they are unlikely to contribute to environmental maintenance or transmission

Moving forward in circles: challenges and opportunities in modelling population cycles

Population cycling is a widespread phenomenon, observed across a multitude of taxa in both laboratory and natural conditions. Historically, the theory associated with population cycles was tightly linked to pairwise consumer–resource interactions and studied via deterministic models, but current empirical and theoretical research reveals a much richer basis for ecological cycles. Stochasticity and seasonality can modulate or create cyclic behaviour in non-intuitive ways, the high-dimensionality in ecological systems can profoundly influence cycling, and so can demographic structure and eco-evolutionary dynamics. An inclusive theory for population cycles, ranging from ecosystem-level to demographic modelling, grounded in observational or experimental data, is therefore necessary to better understand observed cyclical patterns. In turn, by gaining better insight into the drivers of population cycles, we can begin to understand the causes of cycle gain and loss, how biodiversity interacts with population cycling, and how to effectively manage wildly fluctuating populations, all of which are growing domains of ecological research

Data Availability Principles and Practice

publishedVersio

Literacy in Early Intervention for Children with Visual Impairments: Insights from Individual Cases.

A qualitative case study design was used to investigate the ways in which two early interventionists supported emergent literacy development for infants and toddlers with visual impairment. Three themes are addressed: (1) the importance of a family-centered approach in addressing emergent literacy in early intervention; (2) the role of the early interventionist in language and concept development; and (3) the need to focus on the senses as they relate to literacy. The findings provide practical insights into the role of the early interventionist in supporting early literacy development

Targeted Nasal Vaccination Provides Antibody-Independent Protection Against Staphylococcus aureus

Despite showing promise in preclinical models, anti-Staphylococcus aureus vaccines have failed in clinical trials. To date, approaches have focused on neutralizing/opsonizing antibodies; however, vaccines exclusively inducing cellular immunity have not been studied to formally test whether a cellular-only response can protect against infection. We demonstrate that nasal vaccination with targeted nanoparticles loaded with Staphylococcus aureus antigen protects against acute systemic S. aureus infection in the absence of any antigen-specific antibodies. These findings can help inform future developments in staphylococcal vaccine development and studies into the requirements for protective immunity against S. aureu