Exocrine Pancreatic Neoplasms in the Mummichog (Fundulus heteroclitus) from a Creosote-Contaminated Site

A high prevalence of exocrine pancreatic neoplasms occurred in mummichog, Fundulus heteroclitus, from a creosote-contaminated site in the Elizabeth River, Virginia. A total of 20 neoplasms were found in a group of about 1,300 fish obtained at this site over a 2-yr period. Of 240 fish collected during October 1991, 3.3% had pancreatic neoplasms. Adjusted total lesion prevalence for large adult fish (Size Class III: total length = 75–85 mm; Size Class IV: total length \u3e 85 mm) was 6.7%. Pancreatic neoplasms were not observed in 234 fish collected at this site during May 1991, nor were they found in 420 fish obtained during fall 1991 from 1 uncontaminated and 6 moderately contaminated localities. Lesions involved both mesenteric and intrahepatic exocrine pancreas and ranged from well-differentiated acinar cell adenomas to poorly differentiated acinar cell carcinomas. One fish had an atypical acinar cell focus. All specimens with pancreatic neoplasms also had hepatocellular lesions. This epizootic of exocrine pancreatic neoplasia is the first to be reported in a wild fish population. Based on chemical characterization of the site and limited experimental data on chemically induced pancreatic carcinogenesis in other small fish species, the neoplasms were probably caused by exposure of the mummichog to chemical carcinogens in their environment

Parasite Fauna Of 3 Species Of Antarctic Whales With Reference To Their Use As Potential Stock Indicators

Seventeen species of parasites representing the Cestoda, Nematoda, Acanthocephala, and Crustacea are reported from three species of Antarctic whales. Thirty-five sei whales Balaenoptera borealis, 106 minke whales B. acutorostrata, and 35 sperm whales Physeter catodon were examined from latitudes 30-degrees to 64-degrees-S, and between longitudes 106-degrees-E to 108-degrees-W, during the months of November to March 1976-77. Collection localities and regional helminth fauna diversity are plotted on distribution maps. Antarctic host-parasite records from B. borealis, B. acutorostrata, and P. catodon are updated and tabulated by commercial whaling sectors. The use of acanthocephalan parasites of the genus Corynosoma as potential Antarctic sperm whale stock indicators is discussed

Liver carcinogenesis in a non-migratory fish: The association with polycyclic aromatic hydrocarbon exposure

Field and laboratory studies indicate a strong positive association between exposure to chemical pollutants in aquatic environments and development of neoplasia in fishes. This brief communication reviews some of the more important North American and European studies that have been conducted on this relationship. We then review work conducted on a small nonmigratory estuarine cyprinodontid teleost fish, the mummichog (Fundulus heteroclitus) in the industrialized Elizabeth River, Virginia USA. Histopathological surveys of mummichogs from variously degraded habitats indicate an association between PAH exposure and development of neoplasia. We have observed non-neoplastic lesions, preneoplasms and hepatic, biliary, exocrine pancreatic and vascular neoplasms in mummichogs inhabiting Virginia and Maryland estuaries. These lesions track a sediment PAH gradient with highest prevalence occurring in fish from PAI-I-contaminated sites in the industrialized portions of the Elizabeth River, Virginia. Liver metabolizing enzyme profiles typical of those observed in carcinogen-challenged laboratory rodents (e.g., depressed phase I enzymes, elevated phase II enzymes, elevated p-glycoprotein) provided additional support of a chemical etiology for the neoplasms occurring in these fish. Long-term laboratory exposure of mummichogs to creosote-contaminated sediments resulted in development of altered hepatocellular foci and hepatic neoplasms. Biomarkers of fish exposure and effects (e.g., CYPlA induction, bile FA C\u27s, DNA adducts, liver histopathology) are presently used in the Puget Sound, Washington USA and Elizabeth River, Virginia USA to track long-term environmental recovery following habitat remediation

Epizootiology of mycobacteriosis in Chesapeake Bay striped bass (Morone saxatilis): Large-scale field survey

Striped bass in Virginia and Maryland waters of Chesapeake Bay are experiencing an ongoing epizootic of mycobacteriosis. Visceral disease prevalence exceeding 50% has been reported in several locations by various authors, and skin lesion prevalence exceeding 30% has been observed. The high prevalence of skin lesions observed in Chesapeake Bay striped bass is unusual and has not, to our knowledge, been reported previously in wild fishes.https://scholarworks.wm.edu/vimsbooks/1083/thumbnail.jp

Heritable Melanism and Parasitic Infection Both Result in Black-Spotted Mosquitofish

Male Gambusia holbrooki (Eastern Mosquitofish) express a heritable pigmentation polymorphism: ≈99% of males are silver, and only ≈1% have a melanic, black-spotted pattern. Sex-linkage, an autosomal modifier, and temperature control the expression of this heritable melanism. In many teleosts, melanin also accumulates around the site of parasitic invasion. We have identified black-spot disease in wild mosquitofish from their native habitat. Here, we demonstrate convergence upon the black-pigmented phenotype through two means: 1) heritable melanism, and 2) melanic spotting on the silver genotype that results from infection with immature encysted trematodes. Females are silver and express greater avoidance ofmelanic males during mating attempts. The resemblance of the black-spotted pattern of the melanic genotype to that of silver genotype infected with trematodes may affect the fitness ofmelanic males if females perceive them as diseased. Alternatively, females may shun parasitized silverfish because they resemble the melanic genotype, which is larger and has a larger mating orga

The Elizabeth River Monitoring Program 2006-2007: Association Between Mummichog Liver Histopathology And Sediment Chemical Contamination

The Virginia Department of Environmental Quality has conducted an environmental monitoring program in the Elizabeth River, Virginia for several years. The overall aim of this monitoring program has been to develop an assessment of the rivers “health” and to develop methods that would allow DEQ to track the state of the watershed through implementation of a long-term monitoring program for water, sediment and biota. This report summarizes the results from an investigation of mummichog (Fundulus heteroclitus) liver pathology and sediment chemical analyses

AHR-related activities in a creosote-adapted population of adult atlantic killifish, Fundulus heteroclitus, two decades post-EPA superfund status at the Atlantic Wood Site, Portsmouth, VA USA

Atlantic killifish, Fundulus heteroclitus, are adapted to creosote-based PAHs at the US EPA Superfund site known as Atlantic Wood (AW) on the southern branch of the Elizabeth River, VA USA. Subsequent to the discovery of the AW population in the early 1990s, these fish were shown to be recalcitrant to CYP1A induction by PAHs under experimental conditions, and even to the time of this study, killifish embryos collected from the AW site are resistant to developmental deformities typically associated with exposure to PAHs in reference fish. Historically, however, 90 +% of the adult killifish at this site have proliferative hepatic lesions including cancer of varying severity. Several PAHs at this site are known to be ligands for the aryl hydrocarbon receptor (AHR). In this study, AHR-related activities in AW fish collected between 2011 and 2013 were re-examined nearly 2 decades after first discovery. This study shows that CYP1A mRNA expression is three-fold higher in intestines of AW killifish compared to a reference population. Using immunohistochemistry, CYP1A staining in intestines was uniformly positive compared to negative staining in reference fish. Livers of AW killifish were examined by IHC to show that CYP1A and AHR2 protein expression reflect lesions-specific patterns, probably representing differences in intrinsic cellular physiology of the spectrum of proliferative lesions comprising the hepatocarcinogenic process. We also found that COX2 mRNA expression levels were higher in AW fish livers compared to those in the reference population, suggesting a state of chronic inflammation. Overall, these findings suggest that adult AW fish are responsive to AHR signaling, and do express CYP1A and AHR2 proteins in intestines at a level above what was observed in the reference population. (C) 2016 Elsevier B.V. All rights reserved

The Morphology, Development, and Function of Experimentally Induced Macrophage Aggregates in Rivulus Marmoratus.

Calyptospora funduli is a pathogenic coccidium that infects the liver and pancreas of estuarine killifishes belonging to the genus Fundulus. Experimental infection of the atypical fish host Rivulus marmoratus with this intracellular protozoan parasite caused the development of hepatic macrophage aggregates (MA\u27s) and granulomas. The Rivulus/Calyptospora host-parasite system thus represents a new laboratory model for investigations of MA biology. In the present study, this model was used to: (1) examine the morphology and sequential development of the parasite-elicited hepatic MA\u27s in R. marmoratus, (2) define the role that these structures play in the pathogenesis of an infectious disease process, and (3) quantify effects of a selected chemical toxicant on MA, granuloma, and parasite development using morphometric analysis. Histopathological evaluation of R. marmoratus at various time intervals following experimental infection indicates that parasite-elicited hepatic MA\u27s and granulomas represent endstages of a chronic inflammatory process in which a mononuclear phagocyte, apparently derived from the peripheral circulation, plays a prominent role. MA formation is initiated during the gamogonic development of the parasite in response to degenerating gamonts and necrosis of hepatocytes. Granulomas are elicited during sporogony and develop in response to the oocyst stage of the parasite. Sequential histochemical analysis of developing MA\u27s indicates that most of the pigment that is sequestered by these structures is the lipogenic substance ceroid. Melanin is present but not abundant. Ultrastructural analysis of parasite-elicited hepatic MA\u27s suggests that the sequestered pigments are lysosomally derived. Pigment granules are lysosomal residual bodies that are retained by macrophages after the intracellular digestion of phagocytosed host and parasite-derived debris. In addition to the mononuclear phagocyte, five other morphologically distinct leukocytes are associated with the inflammatory response leading to MA and granuloma formation. Ultrastructurally, the parasite-elicited hepatic MA\u27s resemble those that occur in the spleen and kidney of this species. Exposure of experimentally infected fish to cadmium chloride for 50 days suppressed parasite development and caused a reduction in the number and size of the MA\u27s and granulomas. Cadmium did not measurably affect macrophage function at the tested exposure concentration

Re-Emergence of the Harmful Algal Bloom Species Alexandrium Monilatum in the Chesapeake Bay: Assessing Bloom Dynamics and Potential Health Impacts

Effective management of harmful algal blooms (HABs) within a region requires an understanding of species-specific HAB spatial and temporal distributions, bloom dynamics, as well as potential health impacts. In 2007, the southern Chesapeake Bay witnessed its first blooms of the HAB species Alexandrium monilatum. Since then, A. monilatum has bloomed in the region almost annually. A. monilatum produces the toxin ‘goniodomin A’ and is suspected in local mass mortalities of oyster larvae (Crassostrea virginica) grown for aquaculture and restoration projects. Representatives from Virginia’s multimillion dollar oyster aquaculture industry recently expressed great concern over A. monilatum impacts to their businesses; field and lab studies were designed to address these concerns. Sediment samples were collected from the southwest portion of the Chesapeake Bay in a systematic grid-sampling design to assess cyst (resting cell stage) distributions. Cysts were present in low densities at most sites, and cyst densities were high where blooms had been recorded in previous years. HAB toxicity bioassay methods developed at the Virginia Institute of Marine Science were modified to investigate adverse health impacts of five different A. monilatum cell density treatments on sub-adult oysters (~40-70 mm). Oysters delayed grazing when exposed to high densities (\u3e1000 cells/mL) of A. monilatum. Data from the 2015 bloom season and additional bioassays will be presented. Results from these studies could aid in the prediction of A. monilatum bloom severity and health effects on wild and aquacultured oysters, enabling development of best management practices to minimize impacts to the Virginia oyster industry

Epizootic mycobacteriosis in Chesapeake Bay striped bass: What is the fate of infected fish?

Striped bass (Morone saxatilis) in Chesapeake Bay, USA, are currently experiencing an epizootic of mycobacteriosis. Visceral disease prevalence in resident fish exceeds 50% and prevalence of skin ulcers can exceed 30% in some areas. Two primary hypotheses regarding emergence of this chronic bacterial disease propose that anthropogenic stressors constitute important underlying modulating factorshttps://scholarworks.wm.edu/vimsbooks/1081/thumbnail.jp