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VIMS Articles

Immunology and Infectious Disease

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First Comparison Of French And Australian Oshv-1 Μvars By Bath Exposure, Ca Burge, Kimberly S. Reece, Ak Dhar, P Kirkland, B Morga, L Dégremont, N Faury, B Whipple, A Macintyre, C Friedman Jan 2020

First Comparison Of French And Australian Oshv-1 Μvars By Bath Exposure, Ca Burge, Kimberly S. Reece, Ak Dhar, P Kirkland, B Morga, L Dégremont, N Faury, B Whipple, A Macintyre, C Friedman

VIMS Articles

Economically devastating mortality events of farmed and wild shellfish due to infectious disease have been reported globally. Currently, one of the most significant disease threats to Pacific oyster Crassostrea gigas culture is the ostreid herpesvirus 1 (OsHV-1), in particular the emerging OsHV-1 microvariant genotypes. OsHV-1 microvariants (OsHV-1 μvars) are spreading globally, and concern is high among growers in areas unaffected by OsHV-1. No study to date has compared the relative virulence among variants. We provide the first challenge study comparing survival of naïve juvenile Pacific oysters exposed to OsHV-1 μvars from Australia (AUS μvar) and France (FRA μvar). Oysters challenged ...


Characterization Of Microsporidian Ameson Herrnkindi Sp. Nov. Infecting Caribbean Spiny Lobsters Panulirus Argus, Hamish J. Small, Gd Stentiford, Dc Behringer, Ma Freeman, Nam Atherley, Kimberly S. Reece, Jeffrey D. Shields Oct 2019

Characterization Of Microsporidian Ameson Herrnkindi Sp. Nov. Infecting Caribbean Spiny Lobsters Panulirus Argus, Hamish J. Small, Gd Stentiford, Dc Behringer, Ma Freeman, Nam Atherley, Kimberly S. Reece, Jeffrey D. Shields

VIMS Articles

The Caribbean spiny lobster Panulirus argus supports a large and valuable fishery in the Caribbean Sea. In 2007-2008, a rare microsporidian parasite with spore characteristics typical of the Ameson genus was detected in 2 spiny lobsters from southeast Florida (FL). However, the parasite species was not confirmed by molecular analyses. To address this deficiency, reported here are structural and molecular data on single lobsters displaying comparable ‘cotton-like’ abdominal muscle containing ovoid microsporidian spores found at different locations in FL in 2014 and 2018 and in Saint Kitts and Nevis Islands in 2017. In the lobster from 2014, multiple life stages ...


Parasitic Dinoflagellate Hematodinium Perezi Prevalence In Larval And Juvenile Blue Crabs Callinectes Sapidus From Coastal Bays Of Virginia, Hj Small, Jp Huchin-Mian, Ks Reece, Km Pagenkopp Lohan, Mj Butler Iv, Jd Shields Jun 2019

Parasitic Dinoflagellate Hematodinium Perezi Prevalence In Larval And Juvenile Blue Crabs Callinectes Sapidus From Coastal Bays Of Virginia, Hj Small, Jp Huchin-Mian, Ks Reece, Km Pagenkopp Lohan, Mj Butler Iv, Jd Shields

VIMS Articles

The parasitic dinoflagellate Hematodinium perezi infects the American blue crab Callinectes sapidus and other decapods along the Eastern seaboard and Gulf of Mexico coast of the USA. Large juvenile and adult blue crabs experience high mortality during seasonal outbreaks of H. perezi, but less is known about its presence in the early life history stages of this host. We determined the prevalence of H. perezi in megalopae and early benthic juvenile crabs from multiple locations along the Virginia portion of the Delmarva Peninsula. The DNA of H. perezi was not detected in any megalopae collected from several locations within the ...


Method For Serial Passage Of Infectious Hematopoietic Necrosis Virus (Ihnv) In Rainbow Trout, Juliette Doumayrou, M. Gray Ryan, Andrew R. Wargo Jan 2019

Method For Serial Passage Of Infectious Hematopoietic Necrosis Virus (Ihnv) In Rainbow Trout, Juliette Doumayrou, M. Gray Ryan, Andrew R. Wargo

VIMS Articles

Transmission is a fundamental component of pathogen fitness. A better understanding of pathogen transmission can greatly improve disease management. In particular, controlled studies of multiple rounds of natural transmission (i.e. serial passage) can provide powerful epidemiological and evolutionary inferences. However, such studies are possible in only a few systems because of the challenges in successfully initiating and maintaining transmission in the laboratory. Here we developed an efficient and reproducible cohabitation method for conducting controlled experiments investigating the effects of serial passage on infectious hematopoietic necrosis virus (IHNV) in rainbow trout. This method was used to investigate the transmission efficiency ...


Rising Temperatures, Molting Phenology, And Epizootic Shell Disease In The American Lobster, Maya Groner, Jeffrey D. Shields, Df Landers, J Swenarton, Jm Hoenig Nov 2018

Rising Temperatures, Molting Phenology, And Epizootic Shell Disease In The American Lobster, Maya Groner, Jeffrey D. Shields, Df Landers, J Swenarton, Jm Hoenig

VIMS Articles

Phenological mismatchmaladaptive changes in phenology resulting from altered timing of environmental cuesis an increasing concern in many ecological systems, yet its effects on disease are poorly characterized. American lobster (Homarus americanus) is declining at its southern geographic limit. Rising seawater temperatures are associated with seasonal outbreaks of epizootic shell disease (ESD), which peaks in prevalence in the fall. We used a 34-year mark-recapture data set to investigate relationships between temperature, molting phenology, and ESD in Long Island Sound, where temperatures are increasing at 0.4 degrees C per decade. Our analyses support the hypothesis that phenological mismatch is linked to ...


Bottom-Up Control Of Parasites, David S. Johnson, Richard Heard Oct 2017

Bottom-Up Control Of Parasites, David S. Johnson, Richard Heard

VIMS Articles

Parasitism is a fundamental ecological interaction. Yet we understand relatively little about the ecological role of parasites compared to the role of free-living organisms. Bottom-up theory predicts that resource enhancement will increase the abundance and biomass of free-living organisms. Similarly, parasite abundance and biomass should increase in an ecosystem with resource enhancement. We tested this hypothesis in a landscape-level experiment in which salt marshes (60,000 m2 each) received elevated nutrient concentrations via flooding tidal waters for 11 yr to mimic eutrophication. Nutrient enrichment elevated the densities of the talitrid amphipod, Orchestia grillus, and the density and biomass of its ...


Transmission Routes Maintaining A Viral Pathogen Of Steelhead Trout Within A Complex Multi-Host Assemblage, Rachel Breyta, Ilana Brito, Paige Ferguson, Gael Kurath, Kerry Naish, Maureen Purcell, Ar Wargo, Shannon Ladeau Jan 2017

Transmission Routes Maintaining A Viral Pathogen Of Steelhead Trout Within A Complex Multi-Host Assemblage, Rachel Breyta, Ilana Brito, Paige Ferguson, Gael Kurath, Kerry Naish, Maureen Purcell, Ar Wargo, Shannon Ladeau

VIMS Articles

This is the first comprehensive region wide, spatially explicit epidemiologic analysis of surveillance data of the aquatic viral pathogen infectious hematopoietic necrosis virus (IHNV) infecting native salmonid fish. The pathogen has been documented in the freshwater ecosystem of the Pacific Northwest of North America since the 1950s, and the current report describes the disease ecology of IHNV during 2000-2012. Prevalence of IHNV infection in monitored salmonid host cohorts ranged from 8% to 30%, with the highest levels observed in juvenile steelhead trout. The spatial distribution of all IHNV-infected cohorts was concentrated in two sub-regions of the study area, where historic ...


Characterization Of A Rediscovered Haplosporidian Parasite From Cultured Penaeus Vannamei, Lm Nunam, Dv Lightner, Cr Pantoja, Na Stokes, Kimberly S. Reece Feb 2007

Characterization Of A Rediscovered Haplosporidian Parasite From Cultured Penaeus Vannamei, Lm Nunam, Dv Lightner, Cr Pantoja, Na Stokes, Kimberly S. Reece

VIMS Articles

Mortalities of Penaeus vannamei, cultured in ponds in Belize, Central America, began during the last part of the grow-out cycle during the cold weather months from September 2004 through February 2005. Tissue squashes of infected hepatopancreata and histological examination of infected shrimp revealed that the mortalities might have been caused by an endoparasite. To confirm the diagnosis, DNA was extracted from ethanol preserved hepatopancreata and the small-subunit rRNA gene was sequenced. The 1838 by sequence was novel and phylogenetic analysis placed the P. vannamei parasite within the phylum Haplosporidia as a sister taxon to a clade that includes Bonamia and ...


Globally Distributed Mycobacterial Fish Pathogens Produce A Novel Plasmid-Encoded Toxic Macrolide, Mycolactone F, B S. Ranger, E A. Malone, L Mosi, S Adusumilli, R E. Lee, A Coloni, M Rhodes, Plc Small Nov 2006

Globally Distributed Mycobacterial Fish Pathogens Produce A Novel Plasmid-Encoded Toxic Macrolide, Mycolactone F, B S. Ranger, E A. Malone, L Mosi, S Adusumilli, R E. Lee, A Coloni, M Rhodes, Plc Small

VIMS Articles

Mycobacterium ulcerans and Mycobacterium marinum are closely related pathogens which share an aquatic environment. The pathogenesis of these organisms in humans is limited by their inability to grow above 35 degrees C. M. marinum causes systemic disease in fish but produces localized skin infections in humans. M. ulcerans causes Burulli ulcer, a severe human skin lesion. At the molecular level, M. ulcerans is distinguished from M. marinum by the presence of a virulence plasmid which encodes a macrolide toxin, mycolactone, as well as by hundreds of insertion sequences, particularly IS2404. There has been a global increase in reports of fish ...


Plasmablast And Plasma Cell Production And Distribution In Trout Immune Tissues, E S. Bromage, I M. Kaattari, P Zwollo, S L. Kaattari Jan 2004

Plasmablast And Plasma Cell Production And Distribution In Trout Immune Tissues, E S. Bromage, I M. Kaattari, P Zwollo, S L. Kaattari

VIMS Articles

These studies describe the in vitro and ex vivo generation of plasmablasts and plasma cells in trout (Oncorhynchus mykiss) peripheral blood and splenic and anterior kidney tissues. Cells were derived either from naive trout and cultured with the polyclonal activator, Escherichia coli LPS, or from trout that had been immunized with trinitrophenyl-keyhole limpet hemocyanin. Hydroxyurea was used to resolve populations of replicating (plasmablast) and nonreplicating (plasma cell) Ab-secreting cells (ASC). Complete inhibition of Ig secretion was only observed within the PBL. Both anterior kidney and splenic lymphocytes possessed a subset of ASCs that were hydroxyurea resistant. Thus, in vitro production ...


Are Pfiesteria Species Toxicogenic? Evidence Against Production Of Ichthyotoxins By Pfiesteria Shumwayae, Jp Berry, Kimberly S. Reece, Ks Rein, Dg Baden, Lw Haas, Wl Ribeiro, Jeffrey D. Shields, Rv Snyder, Wolfgang K. Vogelbein, Re Gawley Aug 2002

Are Pfiesteria Species Toxicogenic? Evidence Against Production Of Ichthyotoxins By Pfiesteria Shumwayae, Jp Berry, Kimberly S. Reece, Ks Rein, Dg Baden, Lw Haas, Wl Ribeiro, Jeffrey D. Shields, Rv Snyder, Wolfgang K. Vogelbein, Re Gawley

VIMS Articles

The estuarine genus Pfiesteria has received considerable attention since it was first identified and proposed to be the causative agent of fish kills along the mid-Atlantic coast in 1992. The presumption has been that the mechanism of fish death is by release of one or more toxins by the dinoflagellate. In this report, we challenge the notion that Pfiesteria species produce ichthyotoxins. Specifically, we show that (i) simple centrifugation, with and without ultrasonication, is sufficient to "detoxify" water of actively fish-killing cultures of Pfiesteria shumwayae, (ii) organic extracts of lyophilized cultures are not toxic to fish, (fit) degenerate primers that ...


Reduction In Dna Binding Activity Of The Transcription Factor Pax-5a In B Lymphocytes Of Aged Mice, J Anspach, G Poulsen, I Kaattari, R Pollock, P Zwollo Jan 2001

Reduction In Dna Binding Activity Of The Transcription Factor Pax-5a In B Lymphocytes Of Aged Mice, J Anspach, G Poulsen, I Kaattari, R Pollock, P Zwollo

VIMS Articles

Aging has been associated with intrinsic changes of the humoral immune response, which may lead to an increased occurrence of autoimmune disorders and pathogenic susceptibility. The transcription factor Pax-5 is a key regulator of B cell development. Pax-5a/B cell-specific activator protein and an alternatively spliced isoform, Pax-Sd, may have opposing functions in transcriptional regulation due to the lack of a transactivation domain in Pax-Sd. To study B cell-specific changes that occur during the aging process, we investigated expression patterns of Pax-Sa and Sd in mature B cells of young and aged mice. RNase protection assays showed a similar transcriptional ...


Mortality And Hematology Of Blue Crabs, Callinectes Sapidus, Experimentally Infected With The Parasitic Dinoflagellate Hematodinium Perezi, Jeffrey D. Shields, Christopher M. Squyars Jan 2000

Mortality And Hematology Of Blue Crabs, Callinectes Sapidus, Experimentally Infected With The Parasitic Dinoflagellate Hematodinium Perezi, Jeffrey D. Shields, Christopher M. Squyars

VIMS Articles

On the eastern seaboard of the United States, populations of the blue crab, Callinectes sapidus, experi-ence recurring outbreaks of a parasitic dinoflagellate, Hematodinium perezi. Epizootics fulminate in summer and autumn causing mortalities in high-salinity embayments and estuaries. In laboratory studies, we experimentally investigated host mortality due to the disease, assessed differential hemato-logical changes in infected crabs, and examined proliferation of the parasite.


Potential Role Of Protease-Antiprotease Interactions In Perkinsus Marinus Infection In Crassostrea Spp., M Faisal, Jl Oliver, Sl Kaataari Jan 1999

Potential Role Of Protease-Antiprotease Interactions In Perkinsus Marinus Infection In Crassostrea Spp., M Faisal, Jl Oliver, Sl Kaataari

VIMS Articles

Perkinsus marinus causes devastating losses in populations of the eastern oyster (Crassostrea virginica). Our studies have demonstrated that P. marinus secretes extracellular serine proteases which enhance parasite propagation and compromise host defences. Crassostrea virginica. however, possesses several inhibitors of these proteases. The Pacific oyster (C. gigas) is resistant to P. marinus and possesses protease inhibitors with significantly higher specific activities than those in C. virginica. Interestingly, Crassostrea spp. themselves, elaborate metalloprotease activities which can be detected in their plasma, and are increased during P. marinus infections. Together our work suggests that there may be a broad spectrum of humoral host ...


Environmental Factors And The Infectious Disease Caused By The Protozoan Parasite, Perkinsus Marinus, In Eastern Oysters (Crassostrea Virginica), Fle Chu Jan 1999

Environmental Factors And The Infectious Disease Caused By The Protozoan Parasite, Perkinsus Marinus, In Eastern Oysters (Crassostrea Virginica), Fle Chu

VIMS Articles

Temperature and salinity are two important factors limiting the distribution and abundance of Perkinsus marinus, a protozoan parasite of Eastern oysters (Crassostrea virginica). Results of laboratory studies ale consistent with field observations and clearly demonstrate that P. marinus susceptibility and disease advancement are positively correlated with temperature, salinity and in situ number of infective cells. Laboratory findings also suggest that environmental degradation may enhance the epizootic, although disease caused by P. marinus in oysters is known to be predominantly exacerbated by elevated temperature and salinity. Oysters cellular defence mechanisms appear ineffective in defence against P. marinus. Also, pollutant esposure caused ...


Histopathological Alterations Associated With Perkinsus Spp. Infection In The Softshell Clam Mya Arenaria, Sm Mclaughlin, M Faisal Sep 1998

Histopathological Alterations Associated With Perkinsus Spp. Infection In The Softshell Clam Mya Arenaria, Sm Mclaughlin, M Faisal

VIMS Articles

Softshell clams (Mya arenaria) collected from the Chester River in the upper Chesapeake Bay showed the presence of Perkinsus spp, in similar to 12 % (28/240) Of clams examined. The infection seems to run a mild course with the host prevailing in encapsulating invading parasites. The gills appear to be the major site of infection, however, the parasite was also found in the digestive gland, gonads, and kidneys and occasionally in the tissue and sinuses of adductor muscles. Typically, clusters of protozoal cells were embedded in on amorphous PAS-positive substrate and were surrounded by one or more layers of granulocytes ...


In Vitro Propagation Of Two Perkinsus Species From The Softshell Clam Mya Arenaria, Sm Mclaughlin, M Faisal Jan 1998

In Vitro Propagation Of Two Perkinsus Species From The Softshell Clam Mya Arenaria, Sm Mclaughlin, M Faisal

VIMS Articles

Two continuous, axenic cultures of Perkinsus spp. (H49 and G117)were obtained from the softshell clam Mya arenaria collected from Swan Point in the Chester River, Chesapeake Bay (Maryland).

Isolate H49 was obtained from the hemolymph of a heavily infected clam. Except for their larger size, H49 trophozoites and schizonts exhibited the characteristic morphology of Perkinsus marinus and divided by schizogony. Isolate G117 was obtained from a combined gill/palp sample of a moderately infected clam. Unlike H49, vegetative forms (trophozoites and schizonts) of G117 were present along with prezoosporulation stages in the same culture. In culture, G117 cells multiplied ...


Development Of A Protein-Free Chemically Defined Culture Medium For The Propagation Of The Oyster Pathogen Perkinsus Marinus, Jf Lapeyre, M Faisal Jan 1997

Development Of A Protein-Free Chemically Defined Culture Medium For The Propagation Of The Oyster Pathogen Perkinsus Marinus, Jf Lapeyre, M Faisal

VIMS Articles

In the present study we describe a protein-free, chemically defined culture medium, designated JL-ODRP-3, which supports the propagation of Perkinsus marinus, a parasite of the eastern oyster, Crassotrea virginica. P. marinus adapted rapidly to the defined medium and the growth rate of the protozoan increased significantly following a few subcultures. Two isolates of P. marinus, one from the Chesapeake Bay (Virginia) and the other from the Gulf of Mexico (Texas) were cultured for at least ten passes. The doubling times far the isolates from Virginia and Texas, in Jog phase, were 18 +/- 1.2 and 28.6 +/- 3.2 hours ...


Optimal Culture Conditions For The Propagation Of The Oyster Pathogen Perkinsus Marinus (Apicomplexa) In Protein Deficient Medium, Jf Lapeyre, M Faisal Jan 1996

Optimal Culture Conditions For The Propagation Of The Oyster Pathogen Perkinsus Marinus (Apicomplexa) In Protein Deficient Medium, Jf Lapeyre, M Faisal

VIMS Articles

The protozoan, Perkinsus marinus, acclimated and proliferated in the culture medium JL-ODRP-1 without bovine serum albumin. The principal culture conditions for the optimal propagation of P. marinus in this protein deficient culture medium, were determined. The greatest growth rates of the parasite occurred at 28 degrees C, 661 mOsm/kg and pH 7.5. Decreasing seeding densities from 16 x 10(5) to 1 x 10(5) also increased growth rate. After several passages in the absence of 5% CO2 tension, the growth rate of P. marinus was similar to its original value in the presence of 5% CO2 tension ...


Epizootiology Of Late Summer And Fall Infections Of Oysters By Haplosporidium Nelsoni, And Comparisons To Annual Life Cycle Of Haplosporidium Costalis, A Typical Haplosporidan, J. D. Andrews Jan 1982

Epizootiology Of Late Summer And Fall Infections Of Oysters By Haplosporidium Nelsoni, And Comparisons To Annual Life Cycle Of Haplosporidium Costalis, A Typical Haplosporidan, J. D. Andrews

VIMS Articles

The two haplosporidan parasites that cause diseases of oysters along the middle North Atlantic coast of North America differ in their habitats, in timing of oyster mortalities, and in their adaptations to the host. Haplosporidium nelsoni (MSX) kills oysters throughout the year over a wide range of salinities (about 15 to 30 ppt). It has a long infective period of nearly 6 months. This pathogen rarely completes sporulation in its life cycle in oysters. It is highly pathogenic and exhibits irregular activity suggesting that it is poorly adapted to the host species. In contrast, Haplosporidium costalis (SSO) has a short ...