Seacoast Science Center

Anthropogenic pressures have increased the emergence and spread of infectious diseases in wildlife in recent decades, with cascading impacts on ecosystem dynamics and elevated risk to public health. Understanding factors that contribute to disease severity, and population- and community-level impacts, is critical to predicting and mitigating infectious disease outbreaks. We aimed to investigate how host genetic factors contribute to harbor seal susceptibility to phocine distemper virus (PDV), a virus that has caused variable levels of mortality among pinniped populations across the North Atlantic. We conducted whole-genome sequencing of harbor seals that were stranded during and after a PDV outbreak that occurred in the Northeastern United States in 2018 and used genome-wide association and FST-based approaches to identify genetic variants putatively associated with survival. A subset of harbor seals (10 cases, 10 controls) were sequenced at high coverage (~58×) to generate a reference haplotype panel and impute genotypes in the remaining samples (37 cases, 45 controls), which were sequenced at a lower coverage (~4×). On investigation of 148,644 filtered single nucleotide polymorphisms, we identified 33 candidate genes related to innate and adaptive immunity and 37 genes related to the nervous system that were associated with harbor seal survival. These results provide further evidence for the importance of immunogenetic variation and highlight additional key pathways and biological processes that may confer resistance to PDV. Genome-wide approaches, which can reveal the complexity of genetic variation underpinning disease-associated traits, are critical tools to help us understand and potentially predict the impact of future disease outbreaks.

Natural infections of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) have been documented in over 60 animal species, some distantly related. Several marine mammals have been predicted as highly susceptible to SARS-CoV-2 infection based on the homology of their ACE2 receptors to those of humans. To assess potential exposure of marine mammals to SARS-CoV-2, we conducted an opportunistic survey from 2020 to 2025 and tested 1,808 swabs and 378 serum samples from 21 marine mammal species in the United States. All the swabs tested by RT-qPCR were negative, indicating the absence of active infection. A low level of SARS-CoV-2 neutralizing antibodies was detected in three pinniped species, including Phoca vitulina (harbor seal, 13.6%, 95% CI: 5.2-27.4%), Zalophus californianus (California sea lion, 7%, 95% CI: 1.9-17.0%), and Halichoerus grypus (grey seal, 3.7%, 95% CI: 0.5-12.7%). These findings represent the first serological evidence of SARS-CoV-2 exposure in marine mammals in the United States, highlighting the need for continued monitoring of these populations and further research on SARS-CoV-2 transmission dynamics in wildlife.

Phocine distemper virus (PDV) is a morbillivirus that circulates within pinnipeds in the North Atlantic. PDV has caused two known unusual mortality events (UMEs) in western Europe (1988, 2002), and two UMEs in the northwest Atlantic (2006, 2018). Infrequent cross-species transmission and waning immunity are believed to contribute to periodic outbreaks with high mortality in western Europe. The viral ecology of PDV in the northwest Atlantic is less well defined and outbreaks have exhibited lower mortality than those in western Europe. This study sought to understand the molecular and ecological processes underlying PDV infection in eastern North America. We provide phylogenetic evidence that PDV was introduced into northwest Atlantic pinnipeds by a single lineage and is now endemic in local populations. Serological and viral screening of pinniped surveillance samples from 2006 onward suggest there is continued circulation of PDV outside of UMEs among multiple species with and without clinical signs. We report six full genome sequences and nine partial sequences derived from harbour and grey seals in the northwest Atlantic from 2011 through 2018, including a possible regional variant. Work presented here provides a framework towards greater understanding of how recovering populations and shifting species may impact disease transmission.

Cyanide (both HCN and CN- are represented by CN) has multiple industrial applications, is commonly found in some foods, and is a component of fire smoke. Upon exposure, CN blocks production of adenosine triphosphate, causing cellular hypoxia and cytotoxic anoxia, which can eventually result in death. Considering CN's quick onset of action and the long analysis times associated with current techniques, the objective of this study was to develop and validate a rapid and field-portable sensor to detect blood CN concentrations focusing on both concentration and diagnostic accuracy. The sensor takes advantage of the chemical properties of CN by converting it exclusively to HCN via acidification of whole blood. High-speed headspace transfer is used to deliver HCN to a capture solution where it is reacted with naphthalene dialdehyde and taurine to produce a fluorescent beta-isoindole product. Simple spectrofluorometric analysis of the product provides quantitative analysis of CN from whole blood in 60 s and requires only 25 mu L of blood (obtainable via fingerstick). A limit of detection of 5 mu M, a linear range of 10 -200 mu M (with >= 15 mu M considered CN exposed), and excellent accuracy (100 +/- 15%) and precision (<= 15.2% relative standard deviation) were obtained. To evaluate the diagnostic accuracy of the sensor, rabbit blood samples (N = 190, including 24 blinded samples) were analyzed by both the sensor and a lab-based spectrophotometric method. An excellent positive correlation was obtained between the sensor and the lab-based method (R-2 > 0.995) confirming the concentration accuracy of the CN sensor. Moreover, the sensor produced no false positives or negatives when diagnosing CN poisoning. (C) 2019 Elsevier B.V. All rights reserved.

We report γ-ray dosimeters using carbon nanotubes wrapped with metastable poly(olefin sulfone)s (POSs) that readily depolymerize when exposed to ionizing radiation. New POSs, designed for wrapping single-walled carbon nanotubes (SWCNTs), are synthesized and characterized. The resulting POS-SWCNT composites serve as the active transducer in a novel class of γ-ray dosimeters. In our devices, polymer degradation results in immediate changes in the electronic potential of the POS-SWCNT active layers by decreasing the electron tunneling barriers between individualized tubes and by creating enhanced cofacial π-π electron contacts. By incorporating the SWCNT-POS composites into small resistive device platforms, we establish a rare example of real-time detection and dosimetry of radioactive ionizing radiation using organic-based materials. We show that the sensitivity of our platform closely depends on the intrinsic stability of the polymer matrix, the opacity toward γ-rays, and the dispersion efficiency (i.e., the individualization and isolation of the individual SWCNT charge carriers). Resistance decreases up to 65% after irradiation with a 40 krad dose demonstrates the high sensitivity of this novel class of γ-ray sensors. In addition, the detection mechanism was evaluated using a commercial capacitive device platform. The ease of fabrication and low power consumption of these small and inexpensive sensor platforms combined with appealing sensitivity parameters establishes the potential of the poly(olefin sulfone)-SWCNT composites to serve as a new transduction material in γ-ray sensor applications.