Differential Survival of Ichthyophonus Isolates Indicates Parasite Adaptation to its Host Environment

Hershberger, Paul K.; Pacheco, César; Gregg, Jacob L.; Purcell, Maureen K.; LaPatra, Scott E.

doi:10.1645/ge-1553.1

Cited by 17 publications

(11 citation statements)

References 17 publications

(25 reference statements)

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“…EU124916) [87] and to Ichthyophorus hoferi (EU332789), a well-known cosmopolitan parasite of marine fishes [88]. However, the similarity between these two sequences and our clones was low, ranging from 88% to 95% (Table S1).…”

Section: Discussionmentioning

confidence: 85%

Microbial Diversity of a Brazilian Coastal Region Influenced by an Upwelling System and Anthropogenic Activity

et al. 2011

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BackgroundUpwelling systems are characterised by an intense primary biomass production in the surface (warmest) water after the outcrop of the bottom (coldest) water, which is rich in nutrients. Although it is known that the microbial assemblage plays an important role in the food chain of marine systems and that the upwelling systems that occur in southwest Brazil drive the complex dynamics of the food chain, little is known about the microbial composition present in this region.Methodology/Principal FindingsWe carried out a molecular survey based on SSU rRNA gene from the three domains of the phylogenetic tree of life present in a tropical upwelling region (Arraial do Cabo, Rio de Janeiro, Brazil). The aim was to analyse the horizontal and vertical variations of the microbial composition in two geographically close areas influenced by anthropogenic activity (sewage disposal/port activity) and upwelling phenomena, respectively. A lower estimated diversity of microorganisms of the three domains of the phylogenetic tree of life was found in the water of the area influenced by anthropogenic activity compared to the area influenced by upwelling phenomena. We observed a heterogenic distribution of the relative abundance of taxonomic groups, especially in the Archaea and Eukarya domains. The bacterial community was dominated by Proteobacteria, Cyanobacteria and Bacteroidetes phyla, whereas the microeukaryotic community was dominated by Metazoa, Fungi, Alveolata and Stramenopile. The estimated archaeal diversity was the lowest of the three domains and was dominated by uncharacterised marine Crenarchaeota that were most closely related to Marine Group I.Conclusions/SignificanceThe variety of conditions and the presence of different microbial assemblages indicated that the area of Arraial do Cabo can be used as a model for detailed studies that contemplate the correlation between pollution-indicating parameters and the depletion of microbial diversity in areas close to anthropogenic activity; functional roles and geochemical processes; phylogeny of the uncharacterised diversity; and seasonal variations of the microbial assemblages.

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Section: Discussionmentioning

confidence: 85%

Microbial Diversity of a Brazilian Coastal Region Influenced by an Upwelling System and Anthropogenic Activity

et al. 2011

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“…However, a high potential exists for the future establishment of a freshwater life history based on elevated riverine infection pressures (Fig. 2), low parasite host specificity (reviewed in McVicar 1999), plasticity of parasite life stages and life history strategies (Okamoto et al 1985;Kocan et al in press), and precedent for Ichthyophonus establishment in other freshwater systems (Rucker and Gustafson 1953;Erickson 1965;Hershberger et al 2008;Rasmussen et al 2010). Therefore, it is recommended that further expansion of Ichthyophonus throughout the Columbia River system be assessed through continued surveillance efforts in other resident and anadromous fishes.…”

Section: Discussionmentioning

confidence: 99%

Amplification and transport of an endemic fish disease by an introduced species

et al. 2010

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The introduction of American shad from the Atlantic to the Pacific coast of North America in the late 1800's and the subsequent population expansion in the 1980's resulted in the amplification of Ichthyophonus sp., a Mesomycetozoean parasite of wild marine fishes. Sequence analysis of the ribosomal DNA gene complex (small subunit and internal transcribed spacer regions) and Ichthyophonus epidemiological characteristics indicate a low probability that Ichthyophonus was co-introduced with American shad from the Atlantic; rather, Ichthyophonus was likely endemic to marine areas of the Pacific region and amplified by the expanding population of a highly susceptible host species. The migratory life history of shad resulted in the transport of amplified Ichthyophonus from its endemic region in the NE Pacific to the Columbia River watershed. An Ichthyophonus epizootic occurred among American shad in the Columbia River during 2007, when infection prevalence was 72%, and 57% of the infections were scored as moderate or heavy intensities. The epizootic occurred near the record peak of shad biomass in the Columbia River, and corresponded to an influx of 1,595 mt of infected shad tissues into the Columbia River. A high potential for parasite spillback and the establishment of a freshwater Ichthyophonus life cycle in the Columbia River results from currently elevated infection pressures, broad host range, plasticity in Ichthyophonus life history stages, and precedents for establishment of the parasite in other freshwater systems. The results raise questions regarding the risk for sympatric salmonids and the role of Ichthyophonus as a population-limiting factor affecting American shad in the Columbia River.

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“…However, the presence of Ichthyophonus sp. in planktivorous fishes has led some authors (Hershberger et al, 2008;Kocan et al, 2010) to propose that a free-living stage of the parasite is also a possible route of infection. The inability of the freeliving stage of Ichthyophonus sp.…”

Section: Discussionmentioning

confidence: 99%

Parasites and hystopathology of <i>Mullus barbatus</i> and <i>Citharus linguatula</i> (Pisces) from two sites in the NW Mediterranean with different degrees of pollution

Carreras-Aubets¹,

Montero²,

Padrós³

et al. 2010

Sci. Mar.

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SUMMARY: The usefulness of fish parasite communities as bioindicators of environmental stress was tested on two benthic fish species, the red mullet (Mullus barbatus) and the spotted flounder (Citharus linguatula), during the spring of 2006 at two sites of the Catalan coast (northwestern Mediterranean): an anthropogenic-impacted area located close to the city of Barcelona, and a less polluted area close to Blanes (Girona). Gonadosomatic and hepatosomatic indices and condition factor were determined for the fishes caught. Prevalence, mean intensity, mean abundance and species richness of the parasites found in the survey were calculated for both species and locations, and the main histological alterations were recorded. Cysts of unknown aetiology and intestinal coccidians were reported only in red mullets from the area close to Barcelona, which were highly parasitized by the digenean Opecoeloides furcatus and the nematode Capillaria sp. However, a higher prevalence of Ichthyophonus sp. was reported in the spotted flounder from Blanes. Cysts of unknown aetiology, some nematodes and Ichthyophonus sp. may be associated with pollution.Keywords: bioindicators, Mediterranean, Mullus barbatus, Citharus linguatula, cysts of unknown etiology (CUEs), Ichthyophonus sp. RESUMEN: Parásitos e histopatología de Mullus barbatus y Citharus linguatula de dos zonas sometidas a diferente grado de contaminación del Mediterráneo noroccidental. -Se ha comparado la utilidad de las comunidades parasíticas de peces como bioindicadores de estrés ambiental en dos especies bentónicas de peces , el salmonete de fango Mullus barbatus y la solleta Citharus linguatula, durante la primavera de 2006 en dos lugares de la costa catalana (Mediterráneo NO): un área fuertemente impactada cerca de la ciudad de Barcelona, y una menos contaminada cerca de Blanes (Girona). Se determinó el índice gonadosomático, el índice hepatosomático y el factor de condición de los peces capturados. Se calculó la prevalencia, intensidad media, abundancia media y riqueza específica de los diferentes parásitos encontrados por especie y localidad, y se analizaron las principales alteraciones histológicas. Se han encontrado quistes de etiología desconocida y coccidios intestinales tan sólo en los ejemplares de M. barbatus de Barcelona, los cuales también estaban altamente parasitados por el digeneo Opecoeloides furcatus y el nematodo Capillaria sp. Se ha detectado Ichthyophonus sp. tan sólo en los ejemplares de C. linguatula, presentando una mayor prevalencia en los ejemplares de Blanes. Los quistes de etiología desconocida, algunos nematodos e Ichthyophonus sp. podrían estar relacionados con la contaminación.

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Differential Survival of Ichthyophonus Isolates Indicates Parasite Adaptation to its Host Environment

Cited by 17 publications

References 17 publications

Microbial Diversity of a Brazilian Coastal Region Influenced by an Upwelling System and Anthropogenic Activity

Microbial Diversity of a Brazilian Coastal Region Influenced by an Upwelling System and Anthropogenic Activity

Amplification and transport of an endemic fish disease by an introduced species

Parasites and hystopathology of <i>Mullus barbatus</i> and <i>Citharus linguatula</i> (Pisces) from two sites in the NW Mediterranean with different degrees of pollution

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