Evaluation of fatty acids and carnitine as biomarkers of PFOS exposure in biota (fish and dolphin) from Galveston Bay and the northwestern Gulf of Mexico.

Perfluorooctane sulfonate (PFOS) is a ubiquitous pollutant that elicits a wide range of toxic effects in exposed biota. Coastal zones in highly urbanized or industrial areas are particularly vulnerable to PFOS pollution. At present, information is lacking on biomarkers to assess PFOS effects on aquatic wildlife. This study investigated the efficacy of l-carnitine (or carnitine) and fatty acids as biomarkers of PFOS exposure in aquatic biota. The levels of PFOS, total and free carnitine, and 24 fatty acids (measured as fatty acid methyl esters or FAMEs) were measured in the liver, and muscle or blubber, of fish and dolphins sampled from Galveston Bay and the northern Gulf of Mexico (nGoM). Overall, bottlenose dolphins (Tursiops truncatus) had the highest hepatic PFOS levels. Galveston Bay fish, gafftopsail catfish (Bagre marinus), red drum (Sciaenops ocellatus), and spotted seatrout (Cynoscion nebulosus), had hepatic PFOS levels ∼8-13× higher than nGoM pelagic fish species, red snapper (Lutjanus campechanus) and yellowfin tuna (Thunnus albacares). The multivariate analysis of PFOS liver body-burdens and biomarkers found carnitine to be a more modal biomarker of PFOS exposure than FAMEs. Significant positive correlation of hepatic PFOS levels with total carnitine was evident for biota from Galveston Bay (fish only), and a significant correlation between PFOS and total and free carnitine was evident for biota from the nGoM (fish and dolphins). Given the essential role of carnitine in mediating fatty acid ß-oxidation, our results suggest carnitine to be a likely candidate biomarker of environmental PFOS exposure and indicative of potential dyslipidemia effects.

Draft Genome Sequences of Erysipelothrix sp. Strains Isolated from Stranded Septic Bottlenose Dolphins in Alabama, USA.

We report the genome sequences of two Erysipelothrix isolates from fatal cases of sepsis in bottlenose dolphins (Tursiops truncatus). The genomes were found to be most closely related to Erysipelothrix rhusiopathiae and Erysipelothrix piscisicarius. This information expands our knowledge of the genetic characteristics of this pathogen, which can affect free-ranging marine mammals.

Survival of an Indian Ocean humpback dolphin Sousa plumbea in the wild despite chronic osteologic pathologies.

Skeletal examination of a female adult Indian Ocean humpback dolphin Sousa plumbea from South Africa suggested a chronic disease process. It manifested as erosions and pitting of the atlanto-occipital articulation as well as circumferential hyperostosis and ankylosis of some of the caudal vertebrae, findings rarely recorded together in the same animal. The character of the erosive process and vertebral fusion appeared chronic, and further findings of underdevelopment of the fluke, sternum and left humerus with remodeling of the periarticular region of the left scapula may support initiation of the process early in life. Because such chronic pathology would have affected the individual's locomotion and foraging abilities, we also postulate how this individual survived until its demise in a human-derived environmental hazard. Ecological and socio-behavioral aspects observed in S. plumbea, including habitat preference for inshore and shallow waters, small social group aggregations and feeding cooperation, may have contributed to its ability to survive.

Experimental Infection of Domestic Piglets (Sus scrofa) with Rift Valley Fever Virus.

Rift Valley fever phlebovirus (RVFV) is a mosquito-transmitted phlebovirus (Family: Phenuiviridae, Order: Bunyavirales) causing severe neonatal mortality and abortion primarily in domestic ruminants. The susceptibility of young domestic swine to RVFV and this species' role in geographic expansion and establishment of viral endemicity is unclear. Six commercially bred Landrace-cross piglets were inoculated subcutaneously with 105 plaque-forming units of RVFV ZH501 strain and two piglets received a sham inoculum. All animals were monitored for clinical signs, viremia, viral shedding, and antibody response for 14 days. Piglets did not develop evidence of clinical disease, become febrile, or experience decreased weight gain during the study period. A brief lymphopenia followed by progressive lymphocytosis was observed following inoculation in all piglets. Four piglets developed a brief viremia for 2 days post-inoculation and three of these had detectable virus in oronasal secretions three days post-inoculation. Primary inoculated piglets seroconverted and those that developed detectable viremias had the highest titers assessed by serum neutralization (1:64-1:256). Two viremic piglets had a lymphoplasmacytic encephalitis with glial nodules; RVFV was not detected by immunohistochemistry in these sections. While young piglets do not appear to readily develop clinical disease following RVFV infection, results suggest swine could be subclinically infected with RVFV.

Chronic Wasting Disease Diagnostic Discrepancies: The Importance of Testing Both Medial Retropharyngeal Lymph Nodes.

Chronic wasting disease (CWD) of white-tailed deer (Odocoileus virginianus) is a fatal neurologic disease that is spreading across North America. A common surveillance protocol for CWD currently involves screening with an enzyme-linked immunosorbent assay (ELISA) followed by confirmatory testing with immunohistochemistry (IHC). Medial retropharyngeal lymph nodes (MRPLN) are the tissue of choice to diagnose CWD in free-ranging white-tailed deer. We examined left and right MRPLN from 101 ELISA-positive deer harvested from 2015 to 2019 to determine the prevalence of cases in which prion protein was not detected by IHC as well as differences in IHC labeling between contralateral lymph nodes. Prion protein was not detected using IHC in either MRPLN in 5.9% (6/101) of cases. There was a significant but weak positive relationship between the number of IHC-positive follicles and ELISA optical density values (R2=0.08, P=0.039). Mean optical density values in IHC-positive MRPLN were higher than in IHC-negative MRPLN; however, this was not statistically significant (P=0.260). Failure to confirm ELISA diagnoses with IHC may have been because the methods tested different areas of MRPLN, or that there were differences in test sensitivity or antibody affinity. An additional 5.9% (6/101) of cases had one IHC-positive MRPLN, whereas the contralateral MRPLN was IHC negative. Therefore, testing a single MRPLN for CWD may lead to false-negative results, regardless of methodology, which highlights the importance of collecting and testing both MRPLN.

The effect of diet on the gastrointestinal microbiome of juvenile rehabilitating green turtles (Chelonia mydas).

Threatened and endangered green turtles (Chelonia mydas) are unique because as juveniles they recruit from pelagic to near-shore waters and shift from an omnivorous to primarily herbivorous diet (i.e. seagrass and algae). Nevertheless, when injured and ill animals are admitted to rehabilitation, animal protein (e.g. seafood) is often offered to combat poor appetite and emaciation. We examined how the fecal microbiome of juvenile green turtles changed in response to a dietary shift during rehabilitation. We collected fecal samples from January 2014 -January 2016 from turtles (N = 17) in rehabilitation at the Georgia Sea Turtle Center and used next generation sequencing to analyze bacterial community composition. Samples were collected at admission, mid-rehabilitation, and recovery, which entailed a shift from a mixed seafood-vegetable diet at admission to a primarily herbivorous diet at recovery. The dominant phyla changed over time, from primarily Firmicutes (55.0%) with less Bacteroidetes (11.4%) at admission, to primarily Bacteroidetes (38.4%) and less Firmicutes (31.8%) at recovery. While the microbiome likely shifts with the changing health status of individuals, this consistent inversion of Bacteroidetes and Firmicutes among individuals likely reflects the increased need for protein digestion, for which Bacteroidetes are important. Firmicutes are significant in metabolizing plant polysaccharides; thus, fewer Firmicutes may result in underutilization of wild diet items in released individuals. This study demonstrates the importance of transitioning rehabilitating green turtles to an herbivorous diet as soon as possible to afford them the best probability of survival.

COMPARISON OF HEMATOLOGICAL, PLASMA BIOCHEMICAL, AND NUTRITIONAL ANALYTES OF REHABILITATING AND APPARENTLY HEALTHY FREE-RANGING ATLANTIC GREEN TURTLES (CHELONIA MYDAS).

Green turtles (Chelonia mydas) are unique because hatchlings and pelagic juveniles are carnivorous, whereas later life stages become primarily herbivorous. Although this dietary shift is well understood, nutritional requirements at each developmental stage are not. Diet selection during rehabilitation is challenging, because turtles are often fed high-protein, low-fiber diets to counteract poor appetite and emaciation, which can result in gastrointestinal disorders. The objective of this study was to analyze hematology, plasma biochemistry, and nutritional analytes to determine the effect of diet on rehabilitating green turtle health and recovery. Turtles in rehabilitation at the Georgia Sea Turtle Center (GSTC) on Jekyll Island, Georgia (n = 21) were sampled at admission, mid-rehabilitation, and recovery. Duration of rehabilitation ranged from 48 to 233 days (mean = 117) and included a shift from a mixed seafood-vegetable diet at admission to a primarily herbivorous diet at recovery. For comparison, free-ranging turtles captured during an ongoing monitoring project in St. Lucie County, Florida (n = 34) were evaluated for the same variables. Several analytes improved during rehabilitation, including total protein, uric acid, potassium, and vitamins A and E. Others were significantly different, including higher cholesterol and triglycerides, but lower calcium, vitamin D, and magnesium in recovery compared with freeranging turtles. These variations illustrate the benefits of appropriate supportive care during rehabilitation as well as the importance of a species-specific diet for green turtles, and may facilitate formulation of nutritionally complete gel diets for this species under human care.