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1.
Dis Aquat Organ ; 143: 79-100, 2021 Feb 11.
Artigo em Inglês | MEDLINE | ID: mdl-33570042

RESUMO

The response of macrophage aggregates in fish to a variety of environmental stressors has been useful as a biomarker of exposure to habitat degradation. Total volume of macrophage aggregates (MAV) was estimated in the liver and spleen of white perch Morone americana from Chesapeake Bay using stereological approaches. Hepatic and splenic MAV were compared between fish populations from the rural Choptank River (n = 122) and the highly urbanized Severn River (n = 131). Hepatic and splenic MAV increased with fish age, were greater in females from the Severn River only, and were significantly greater in fish from the more polluted Severn River (higher concentrations of polycyclic aromatic hydrocarbons, organochlorine pesticides, and brominated diphenyl ethers). Water temperature and dissolved oxygen had a significant effect on organ volumes, but not on MAV. Age and river were most influential on hepatic and splenic MAV, suggesting that increased MAV in Severn River fish resulted from chronic exposures to higher concentrations of environmental contaminants and other stressors. Hemosiderin was abundant in 97% of spleens and was inversely related to fish condition and positively related to fish age and trematode infections. Minor amounts of hemosiderin were detected in 30% of livers and positively related to concentrations of benzo[a]pyrene metabolite equivalents in the bile. This study demonstrated that hepatic and splenic MAV were useful indicators in fish from the 2 tributaries with different land use characteristics and concentrations of environmental contaminants. More data are needed from additional tributaries with a wider gradient of environmental impacts to validate our results in this species.


Assuntos
Bass , Doenças dos Peixes , Poluentes Químicos da Água , Animais , Baías , Monitoramento Ambiental , Feminino , Macrófagos , Rios
2.
Dis Aquat Organ ; 143: 119-127, 2021 Feb 11.
Artigo em Inglês | MEDLINE | ID: mdl-33570045

RESUMO

Sea lice are amongst the most ecologically and economically damaging parasites of farmed salmonids globally. Spill-over from aquaculture can increase parasite pressure on wild fish populations, but quantifying this effect is challenging due to the relative paucity of data available on 'natural' salmonid louse burdens in the absence of aquaculture, particularly for Atlantic salmon Salmo salar. Here, wild Atlantic salmon and sea trout S. trutta were screened at the tidal limit of the River Tamar (UK) for the presence of sea lice. During 2013 and 2015, the prevalence of sea lice ranged from 41 (n = 361) to 60% (n = 275) and 55 (n = 882) to 58% (n = 800) in Atlantic salmon and sea trout, respectively. All sea lice collected were identified as Lepeophtheirus salmonis. Mean L. salmonis infection intensity across the study period was 5.84 (range: 1-66) in Atlantic salmon and 6.45 (range: 1-37) in sea trout. Infection intensity was positively correlated with the amount of external damage present for both fish species. Given that the fish were examined when returning to freshwater, the lice burdens obtained may represent an underestimate. Nevertheless, these data provide important baseline information on 'natural' sea louse infections in South West England, which has been proposed as a potential region for aquaculture development.


Assuntos
Copépodes , Doenças dos Peixes , Salmo salar , Animais , Inglaterra , Doenças dos Peixes/epidemiologia , Rios , Truta , Reino Unido
3.
Dis Aquat Organ ; 143: 129-138, 2021 Feb 11.
Artigo em Inglês | MEDLINE | ID: mdl-33570046

RESUMO

Ichthyophonus infection was first detected in Peruvian Oncorhynchus mykiss in 1986, but the occurrence of ichthyophonosis disease in the region is unknown. This study investigated the presence and distribution of Ichthyophonus sp. in Peruvian rainbow trout using traditional and DNA sequencing tools. Between 2007 and 2008, 205 rainbow trout from 13 hatcheries in the Mantaro river basin were examined for the presence of Ichthyophonus, and at that time only 3 farms were positive. This early study confirmed the presence of Ichthyophonus sp. in the Tranca Grande lagoon for the first time, at a prevalence of 50%. In 2012, examination of 240 trout from 24 fish farms in 2 Peruvian Departments found 9 infected farms. More recently, in 2018, Ichthyophonus sp. was found in Lake Titicaca, infecting a trout in the Ichu area (in the Department of Puno). Our molecular analysis of the infected trout showed that ichthyophonosis disease in the Peruvian trout was caused by Ichthyophonus sp. Clade C. The finding of this pathogen in Lake Titicaca should be an alert for nearby farms and entities dealing with fish of economic importance in the rivers of Peru.


Assuntos
Doenças dos Peixes , Mesomycetozoea , Oncorhynchus mykiss , Animais , Doenças dos Peixes/epidemiologia , Mesomycetozoea/genética , Peru/epidemiologia , Rios
4.
Viruses ; 13(2)2021 02 07.
Artigo em Inglês | MEDLINE | ID: mdl-33562288

RESUMO

Carassius auratus herpesvirus (CaHV) has been identified as a high-virulence pathogenic virus that infects aquatic animals, but the key factor for virus-host interaction is still unclear. Five Really interesting new genes (RING) finger proteins (39L, 52L, 131R, 136L, and 143R) of CaHV were screened to determine structural diversity. RING finger proteins were also predicted in other known fish herpesviruses, with an arrangement and number similar to CaHV. We performed multifaceted analyses of the proteins, including protein sizes, skeleton structures, subcellular localizations, and ubiquitination activities, to determine their precise roles in virus-host interactions. The five proteins were overexpressed and detected different levels of ubiquitination activities, and 143R showed the highest activity. Then, the prokaryotic expressed and purified full-length proteins (131R and 136L), RING domain isolates (131R12-43 and 136L45-87), and RING domain-deleted mutants (131RΔ12-43 and 136LΔ45-87) were prepared to detect their activities through ubiquitination assays. The results indicate that both full-length proteins and their isolates have activities that catalyze ubiquitination, and the full-length proteins possess higher activity than the isolates, but RING domain-deleted mutants lose their activities. Furthermore, the activities of the five proteins were verified as E3 ubiquitin ligase activity, showing that the RING domains determine the ubiquitination activity. These proteins present different subcellular localization. RING domain-deleted mutants showed similar subcellular localization with their full-length proteins, and all the isolates diffused in whole cells. The current results indicate that the sequence outside the RING domain determines subcellular localization and the level of ubiquitination activity, suggesting that the RING finger proteins of fish herpesviruses might have diverse functions in virus-host interaction.


Assuntos
Herpesviridae/metabolismo , Proteínas Virais/química , Proteínas Virais/metabolismo , Animais , Doenças dos Peixes/virologia , Carpa Dourada/virologia , Células HEK293 , Herpesviridae/genética , Herpesviridae/fisiologia , Infecções por Herpesviridae/veterinária , Infecções por Herpesviridae/virologia , Interações Hospedeiro-Patógeno , Humanos , Espaço Intracelular/metabolismo , Mutação , Domínios RING Finger/genética , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Ubiquitina-Proteína Ligases/química , Ubiquitina-Proteína Ligases/genética , Ubiquitina-Proteína Ligases/metabolismo , Ubiquitinação , Proteínas Virais/genética
5.
Dis Aquat Organ ; 143: 159-168, 2021 Feb 25.
Artigo em Inglês | MEDLINE | ID: mdl-33632994

RESUMO

We investigated the cause of skeletal deformities found in brown trout from the Aspromonte mountain area in Reggio Calabria, Italy. Toxicological, histopathological and parasitological analyses were carried out on 14 fish with evident macro-morphological alterations from 2 different locations in the same river, and 4 control fish without morphological alterations from a different river (far from the first river but still within the area under study). Histopathological and radiological observations confirmed severe skeletal deformities in the specimens investigated. Parasitological examinations highlighted the presence of the nematode Cystidicoloides ephemeridarum, found only within the gastrointestinal tract of specimens showing deformities. Moreover, a direct correlation between parasite number and fish size was found. Given the low heavy metal levels and the presence of a massive parasitosis in teleosts showing deformities, we postulate a correlation between skeletal deformities and nematode infestation: the parasites caused a serious vitamin and mineral deficiency in the fish, which led to a dysplastic vertebral column. The low calcium levels found in malformed specimens compared with negative controls effectively confirm this hypothesis.


Assuntos
Doenças dos Peixes , Animais , Itália , Truta
6.
Oecologia ; 195(1): 155-161, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33387006

RESUMO

The reduction in host fitness caused by parasite infections (virulence) depends on infection intensity and the degree of damage caused per parasite. Environmental conditions can shape both virulence components, but in contrast to infection intensity, environmental impacts on per-parasite damage are poorly understood. Here, we studied the effect of ambient temperature on per-parasite damage, which is jointly determined by the ability of parasites to induce harm (per-parasite pathogenicity) and the ability of hosts to limit damage (tolerance). We experimentally exposed two salmonid species, Atlantic salmon (Salmo salar) and sea trout (Salmo trutta), to replicated genotypes of the eye fluke Diplostomum pseudospathaceum. After development of health damage (eye cataracts) in warm water (16 °C) during the first 12 weeks post exposure, we maintained the fish at either 5 °C (cold water) or 16 °C for another 8 weeks and quantified changes in cataracts as a function of parasite load. We found that per-parasite damage was reduced in cold compared to warm water, suggesting that cold temperatures improved host health. Per-parasite damage was also affected by parasite genotype and host species, but these effects did not change with temperature. Our findings suggest that cold-water seasons, which are often neglected in host-parasite studies due to low infection risk, could allow hosts to recuperate and thus, may have important implications for the ecology and epidemiology of parasite infections.


Assuntos
Doenças dos Peixes , Parasitos , Salmo salar , Trematódeos , Animais , Interações Hospedeiro-Parasita , Truta , Água
7.
Dis Aquat Organ ; 143: 37-50, 2021 Jan 28.
Artigo em Inglês | MEDLINE | ID: mdl-33506814

RESUMO

Studies of ectoparasites of wild-caught queenfish Scomberoides commersonnianus from several areas in northern Australia were reviewed to investigate relationships between parasite burdens, environmental conditions and external lesions. A sample of 27 queenfish captured near a dredge spoil disposal site in Gladstone Harbour, Queensland, Australia, in January 2012 was anomalous, with a high percentage of fish (66.6%) exhibiting grossly visible skin lesions including foci of erythema and petechial haemorrhages, particularly on the pectoral girdle and ventrolateral surfaces. Microscopically, lesions comprised acute epidermal erosion, ulceration and/or perivascular dermatitis with dermal oedema and depigmentation. Skin lesions were associated with high prevalence (100%) and intensity (mean = 21.2 copepods fish-1, range 4-46) of infection by sea lice Lepeophtheirus spinifer. Only queenfish infected with >10 L. spinifer presented with skin lesions. This is the first record of L. spinifer from Australia. In contrast, grossly visible skin lesions were not reported from queenfish (n = 152) sampled from other sites in the Northern Territory and Queensland, where the sampled fish had a much lower prevalence (51.3%) and intensity (mean = 3.54, range 0-26) of copepod (L. spinifer, Caligus spp. and Tuxophorus sp.) infections. Copepods from queenfish in studies undertaken outside Gladstone Harbour exhibited an over-dispersed pattern of infection, with the vast majority (n = 137, or 90.1%) of fish infected with <5 copepods. These data demonstrate that heavy L. spinifer infections, combined with poor water quality and/or direct exposure to contaminated dredge spoil and blooms of the cyanobacterium Lyngbya majuscula, can be associated with cutaneous disease in wild-caught queenfish.


Assuntos
Copépodes , Doenças dos Peixes , Perciformes , Animais , Austrália , Doenças dos Peixes/epidemiologia , Peixes , Queensland/epidemiologia
8.
Dis Aquat Organ ; 143: 51-56, 2021 Jan 28.
Artigo em Inglês | MEDLINE | ID: mdl-33506815

RESUMO

Myxobolus cerebralis (Hofer, 1903), the etiological agent of salmonid whirling disease, reportedly matures in only the oligochaete 'Tubifex tubifex'. The concept of 'T. tubifex' is problematic because it is renowned as a species complex (or having 'strains'), and many sequences ascribed to this taxon in GenBank are misidentified or indicate several cryptic species. These facts cast doubt on the long-held notion that M. cerebralis is strictly host-specific to the single definitive host, T. tubifex. Herein, as part of an ongoing regional whirling disease monitoring project, oligochaetes (452 specimens) were collected from 31 riverine sites in western North Carolina (August through September 2015) and screened for infection by M. cerebralis. The species-specific nested PCR for M. cerebralis was positive for 8 oligochaete specimens from the French Broad River Basin (Mill Creek and Watauga River) and New River Basin (Big Horse Creek). We individually barcoded these M. cerebralis-positive oligochaete specimens using cytochrome oxidase 1 (CO1) primers and then conducted a Bayesian inference phylogenetic analysis. We identified 2 oligochaete genotypes: one sister to a clade comprising Limnodrilus udekemianus (Haplotaxida: Naididae) and another sister to Limnodrilus hoffmeisteri. This is the first detection of M. cerebralis from an oligochaete in the SE USA and the first detection of M. cerebralis from an oligochaete other than T. tubifex. These results suggest that other non-T. tubifex definitive hosts can harbor the pathogen and should be considered in the context of fish hatchery biosecurity and monitoring wild trout streams for M. cerebralis and whirling disease in the southeastern USA.


Assuntos
Doenças dos Peixes , Doenças dos Cavalos , Myxobolus , Oligoquetos , Animais , Teorema de Bayes , Eucariotos , Cavalos , Myxobolus/genética , North Carolina , Filogenia
9.
Int J Food Microbiol ; 337: 108930, 2021 Jan 16.
Artigo em Inglês | MEDLINE | ID: mdl-33161348

RESUMO

Anisakiasis is a gastrointestinal disease caused by parasitic anisakid nematodes, mainly Anisakis simplex sensu stricto (A. simplex). Anisakiasis is prevalent in Japan and approximately 40% of anisakiasis cases in Tokyo occur through the consumption of raw or marinated mackerel. However, in 2018, there was a sudden increase in the number of the food poisoning cases in Tokyo caused by consumption of skipjack tuna (Katsuwonus pelamis). Therefore, we investigated anisakiasis cases resulting from ingestion of skipjack tuna in Tokyo, and surveyed the presence of Anisakis larvae in skipjack tuna in 2018 and 2019. Nineteen samples from 15 patients (13 in 2018 and 2 in 2019) with anisakiasis surely caused by ingestion of skipjack tuna were all identified as A. simplex. The higher mean abundance of Anisakis simplex larvae in skipjack tuna muscle in May 2018 (1.30; 13 larvae/10 fishes) compared to that in the other periods was regarded as a contributing factor in the increase in anisakiasis cases by ingesting skipjack tuna in 2018. To verify whether Anisakis larvae migrate from the visceral organs to the muscle during the period from fishing on the boat until processing for sale, the number of Anisakis larvae in skipjack tuna caught from August to November 2018 was investigated by removing the visceral organs at three different timings, i.e., immediately after catching, after landing, and after transport to the laboratory. Anisakis larvae were detected in the muscle irrespective of the timings at which visceral organs were removed. All larvae from the muscle were detected only from the ventral part and were identified as A. simplex. We thus consider that avoiding raw consumption of the ventral muscle should be an effective measure to prevent anisakiasis.


Assuntos
Anisaquíase/parasitologia , Parasitologia de Alimentos , Músculos/parasitologia , Alimentos Crus/parasitologia , Atum/parasitologia , Animais , Anisaquíase/epidemiologia , Anisakis/fisiologia , Doenças dos Peixes/parasitologia , Humanos , Larva , Tóquio/epidemiologia
10.
Mar Pollut Bull ; 162: 111904, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33321307

RESUMO

In the last decade, the salmon aquaculture industry has considerably increased the use of lumpfish juveniles as cleaner fish. Potential escape of reared lumpfish into the wild may spread diseases or genetically contaminate wild stocks. The guidelines for minimum sizes of cleaner fish to use in aquaculture cages are currently based on simple mesh penetration tests. However, these guidelines do not consider the potential compressibility of fish or changes in mesh state due to factors such as sea conditions and maintenance operations. This study shows that the industry-recommended minimum stocking sizes for a given mesh size may result in escape risk and that ignoring fish compressibility and mesh state can lead to underestimation of the lumpfish sizes that are able to escape. Our results can be used to develop new guidelines that will contribute to reduced escape of lumpfish from salmonid farms and lessen the potential environmental consequences.


Assuntos
Doenças dos Peixes , Perciformes , Salmonidae , Animais , Aquicultura , Fazendas
11.
Viruses ; 12(12)2020 12 16.
Artigo em Inglês | MEDLINE | ID: mdl-33339349

RESUMO

Here we have studied the impact of lice (Lepeophtheirus salmonis) infestation of donor fish on the ability of isolated peripheral blood monocytes (PMBCs) to control the replication of salmonid alphavirus (SAV) ex vivo. PMBC were collected by Percoll gradients at eight and nine weeks post copepodid infestation of Atlantic salmon post smolt. Uninfested fish were controls. PBMCs were then infected ex vivo with SAV (subtype 3), and samples were collected for analysis at two, four, and six days post virus infection. Virus titer in the supernatant was assayed in CHH-1 cells, and in addition, the relative expression of the virus structural protein E2 and selected host antiviral genes, IRF9, ISG15, Mx, and IFIT5, were assayed using real-time PCR. Significantly higher virus replication was detected in cells collected from lice-infested fish compared to controls. Higher virus titer coincided with an inability to upregulate the expression of different immune genes, IFIT5, IRF9, and Mx. These findings point towards compromised ability of PMBCs from lice-infested fish to control virus replication, and, to our knowledge, is the first report showing the direct effect of lice infestation on the interplay between viruses and immune cells. There is a possible impact on the dynamic spread of viral diseases in the aquatic environment.


Assuntos
Alphavirus/fisiologia , Ectoparasitoses/veterinária , Doenças dos Peixes/imunologia , Interações Hospedeiro-Parasita/imunologia , Monócitos/imunologia , Salmo salar/virologia , Replicação Viral , Animais , Células Cultivadas , Ectoparasitoses/imunologia , Salmo salar/imunologia
12.
Ann Agric Environ Med ; 27(4): 535-539, 2020 Dec 22.
Artigo em Inglês | MEDLINE | ID: mdl-33356057

RESUMO

INTRODUCTION AND OBJECTIVE: Fish mycobacteriosis is a chronic granulomatous disease caused by several species of bacteria from the genus Mycobacterium, described as nontuberculous mycobacteria (NTM). The most important species causing fish mycobacterioses are M. chelonae, M. fortuitum, and M. marinum. Mycobacteria infecting fish also include zoonotic pathogens. M. marinum is the cause of most cases of fish-related mycobacterial infection in humans. The disease occurs more frequently in workers in the fishing industry, people whose hobbies involve water activities, and aquarists. The aim of the present study was to examine the occurrence of different species of mycobacteria in freshwater ornamental fish. MATERIAL AND METHODS: The occurrence of Mycobacterium spp. in freshwater ornamental fish was studied from January 2015 - December 2016. Material isolated from skin scrapings, contents of the digestive tracts, and internal organs of ornamental fish was stained with Ziehl-Neelsen (ZN) and inoculated on Lowenstein-Jensen medium. All isolates found positive by ZN were identified by amplification of the gene encoding the Hsp65 protein. A total of 408 samples obtained from 136 ornamental fish from 36 species were tested. RESULTS: Using the culture method Mycobacterium was isolated from 69 fish (50.1%) and 99 samples (24.3%). Sequence analysis of gene fragments coding for the Hsp65 protein of 99 isolates revealed occurrence of 13 species of mycobacteria: M. abscessus, M. chelonae, M. fortuitum, M. gordonae, M. marinum, M. mucogenicum, M. neoaurum, M. peregrinum, M. salmoniphilum, M. saopaulense, M. senegalense, M. septicum, and M. szulgai. CONCLUSIONS: The obtained results indicate a significant role of ornamental fish as a source of mycobacteria which are potentially dangerous,especially to humans.


Assuntos
Doenças dos Peixes/epidemiologia , Peixes , Infecções por Mycobacterium/veterinária , Mycobacterium/fisiologia , Animais , Doenças dos Peixes/microbiologia , Água Doce , Infecções por Mycobacterium/epidemiologia , Infecções por Mycobacterium/microbiologia , Animais de Estimação , Prevalência
13.
J Parasitol ; 106(6): 809-817, 2020 11 12.
Artigo em Inglês | MEDLINE | ID: mdl-33351948

RESUMO

Here we describe a new species of RhinebothriumLinton, 1890, from Hypanus guttatus (Bloch and Schneider). Rhinebothrium ramosi n. sp. can be differentiated from all 51 valid species of the genus by having 4-5 testes and uterus that extends throughout the entire length of the proglottid. Only 8 of the above species closely resemble R. ramosi in total length (Rhinebothrium bunburyense, Rhinebothrium chollaense, Rhinebothrium corbatai, Rhinebothrium dasyatidis, Rhinebothrium kruppi, Rhinebothrium lintoni, Rhinebothrium margaritense, and Rhinebothrium reydai). Despite the resemblance, R. bunburyense, R. corbatai, R. dasyatidis, R. lintoni, and R. margaritense can be distinguished from the new species by possessing a larger number of proglottids. The remaining 3 species (R. chollaense, R. kruppi, and R. reydai) overlap in total length and number of proglottids with R. ramosi. However, they can be distinguished from the new species by possessing a single posterior-most bothridial loculus instead of arranged as a pair, as found in the new species. This is the first report of the genus from the coastal waters of Brazil and brings to 52 the number of valid species for this genus. Additionally, we use the patterns of infection and distribution for species of Rhinebothrium to make predictions of expected diversity within the genus, especially for unsurveyed hosts in endemic marine ecoregions of the world.


Assuntos
Cestoides/classificação , Infecções por Cestoides/veterinária , Doenças dos Peixes/parasitologia , Rajidae/parasitologia , Animais , Oceano Atlântico , Brasil/epidemiologia , Cestoides/isolamento & purificação , Cestoides/ultraestrutura , Infecções por Cestoides/epidemiologia , Infecções por Cestoides/parasitologia , Doenças dos Peixes/epidemiologia , Intestinos/parasitologia , Microscopia Eletrônica de Varredura/veterinária
14.
J Parasitol ; 106(6): 789-801, 2020 11 12.
Artigo em Inglês | MEDLINE | ID: mdl-33351949

RESUMO

Examination of 4 specimens of the leopard whipray Himantura leoparda, a dasyatid stingray from northern Australia, led to the discovery of 3 new species of Rhinebothrium. Rhinebothrium leopardensis n. sp., Rhinebothrium nandoi n. sp., and Rhinebothrium ruhnkei n. sp. are described, increasing the diversity of the genus to 51 species globally. All 3 new species differ from their congeners in terms of testis number, proglottid number, loculus number, and size. With respect to one another, R. leopardensis n. sp. has bothridia that are weakly constricted at their centers and has a greater number of proglottids than the other 2 species (93-108 vs. 11-15, and 48-78, respectively). Rhinebothrium nandoi n. sp. is the smallest of the 3 species found in H. leoparda (3.6-5 vs. 10-15 mm and 10.1-15.8 mm in total length [TL], respectively) and bears bothridia that are constricted at their centers. Rhinebothrium ruhnkei n. sp. bears bothridia that are conspicuously constricted at their centers and has more testes than R. leopardensis and fewer than R. nandoi (7-10 vs. fewer than 7 and 21-33, respectively). Before this study, 56% (27 of 48) of Rhinebothrium species had been described from the freshwater river systems of South America and the marine waters surrounding South and North America. In contrast, despite the remarkably diverse nature of its batoid fauna, only 19 species were known from the Indo-Pacific region. Our work increases this number to 22, emphasizing the highly underestimated nature of Rhinebothrium diversity in this region of the globe. The discovery of these 3 new species was not unexpected, given the relatively poor status of our current knowledge of the cestode faunas of dasyatid stingrays in the Indo-Pacific region, and given the fact that it is common for a single batoid species to host 2 or more species of Rhinebothrium. Our results suggest that additional work on the cestode faunas of the batoids, especially dasyatids, from the Indo-Pacific region is likely to be highly productive in terms of contributing to the knowledge of Rhinebothrium diversity.


Assuntos
Cestoides/classificação , Infecções por Cestoides/veterinária , Doenças dos Peixes/parasitologia , Rajidae/parasitologia , Animais , Austrália , Cestoides/anatomia & histologia , Cestoides/ultraestrutura , Infecções por Cestoides/parasitologia , Feminino , Enteropatias Parasitárias/parasitologia , Enteropatias Parasitárias/veterinária , Masculino , Microscopia Eletrônica de Varredura/veterinária
15.
J Parasitol ; 106(6): 818-827, 2020 11 12.
Artigo em Inglês | MEDLINE | ID: mdl-33351950

RESUMO

The cestode fauna of Squaliolus aliae was examined for the first time following the collection of elasmobranch specimens from Taiwan in 2005, 2013, and 2017. This small shark was found to host 2 tapeworm species. These consist of Acanthobothrium katherineae n. sp., which is new to science and is described herein, and a second species, in the genus Scyphophyllidium, which also appears to be new, but which is represented by insufficient material for formal description. Acanthobothrium katherineae is a category 5 species. It can be distinguished from 5 of the 19 other category 5 species in that it is apolytic, retaining proglottids on its strobila until they are gravid. This new species differs from the remaining 14 category 5 species in its combination of the following features: It is a smaller worm, has fewer than 100 proglottids, has a relatively short cephalic peduncle, and differs in bothridial size and loculus ratio. Sequence data for the D1-D3 region of the 28S rDNA gene were generated for one specimen of A. katherineae. This sequence, along with comparable sequence data for adults of 14 described and 2 undescribed species as well as specimens of 6 undescribed larval members of the genus, was included in a maximum likelihood phylogenetic analysis. The resulting tree places the shark-hosted A. katherineae within a clade of stingray-hosted species, with Acanthobothrium romanowi as its sister taxon. Acanthobothrium katherineae is 1 of only 19 Acanthobothrium species known to parasitize sharks. The tree resulting from this study, which is preliminary given the relatively poor taxon sampling of the diversity in the genus, included 3 of the shark-parasitizing Acanthobothrium species and suggests that all 3 represent host-switching events. This is the first report of an Acanthobothrium species from the family Dalatiidae and the first report of a Scyphophyllidium species from the order Squaliformes. These findings suggest that other members of the Squaliformes, many of which have not previously been examined for parasites, may host additional novel cestode taxa.


Assuntos
Cestoides/classificação , Infecções por Cestoides/veterinária , Doenças dos Peixes/parasitologia , Tubarões/parasitologia , Animais , Cestoides/genética , Cestoides/isolamento & purificação , Cestoides/ultraestrutura , Infecções por Cestoides/parasitologia , DNA de Helmintos/isolamento & purificação , Feminino , Intestinos/parasitologia , Masculino , Microscopia Eletrônica de Varredura/veterinária , Filogenia , Taiwan
16.
Dis Aquat Organ ; 142: 197-201, 2020 Dec 17.
Artigo em Inglês | MEDLINE | ID: mdl-33331287

RESUMO

Streptococcus iniae causes high mortality in cultured and wild fish stocks globally. Since the first report in captive Amazon river dolphins Inia geoffrensis in 1976, it has emerged in finfish across all continents except Antarctica. In March 2016, an estimated 17000 fish were observed dead and dying along a remote 70 km stretch of the Kimberley coastline north of Broome, Western Australia. Affected species included finfish (lionfish Pterois volitans, angelfish Pomacanthus sp., stripey snapper Lutjanus carponotatus, sand bass Psammoperca waigiensis, yellowtail grunter Amniataba caudavittata, damselfish Pomacentridae sp.), flatback sea turtles Natator depressus, and olive (Aipysurus laevis) and black-ringed (Hydrelaps darwiniensis) sea snakes. Moribund fish collected during the event exhibited exophthalmia and abnormal behaviour, such as spiralling on the surface or within the water column. Subsequent histopathological examination of 2 fish species revealed bacterial septicaemia with chains of Gram-positive cocci seen in multiple organs and within brain tissue. S. iniae was isolated and identified by bacterial culture, species-specific PCR, Matrix-Assisted Laser Desorption Ionisation Time-Of-Flight (MALDI-TOF) and biochemical testing. This is the first report of S. iniae associated with a major multi-species wild marine fish kill in Australia. Extreme weather events in the region including a marked decrease in water temperatures, followed by an extended period of above-average coastal water temperatures, were implicated as stressors potentially contributing to this outbreak.


Assuntos
Doenças dos Peixes , Infecções Estreptocócicas , Animais , Austrália , Doenças dos Peixes/epidemiologia , Infecções Estreptocócicas/epidemiologia , Infecções Estreptocócicas/veterinária , Streptococcus iniae , Austrália Ocidental/epidemiologia
17.
Dis Aquat Organ ; 142: 203-211, 2020 Dec 17.
Artigo em Inglês | MEDLINE | ID: mdl-33331288

RESUMO

Salmon pancreas disease virus, more commonly known as salmonid alphavirus (SAV), is a single-stranded positive sense RNA virus and the causative agent of pancreas disease and sleeping disease in salmonids. In this study, a unique strain of SAV previously isolated from ballan wrasse was subjected to whole genome sequencing using nanopore sequencing. In order to accurately examine the evolutionary history of this strain in comparison to other SAV strains, a partitioned phylogenetic analysis was performed to account for variation in the rate of evolution for both individual genes and codon positions. Partitioning the genome alignments almost doubled the observed branch lengths in the phylogenetic tree when compared to the more common approach of applying one model of substitution across the genome and significantly increased the statistical fit of the best-fitting models of nucleotide substitution. Based on the genomic data, a valid case can be made for the viral strain examined in this study to be considered a new SAV genotype. In addition, this study adds to a growing number of studies in which SAV has been found to infect non-salmonid fish, and as such we have suggested that the viral species name be amended to the more inclusive 'piscine alphavirus'.


Assuntos
Infecções por Alphavirus , Alphavirus , Doenças dos Peixes , Nanoporos , Salmo salar , Salmonidae , Alphavirus/genética , Infecções por Alphavirus/veterinária , Animais , Genótipo , Filogenia , Sequenciamento Completo do Genoma/veterinária
18.
Viruses ; 13(1)2020 12 25.
Artigo em Inglês | MEDLINE | ID: mdl-33375689

RESUMO

Viral hemorrhagic septicemia virus (VHSV) is a highly pathogenic virus that infects a wide range of host fish species causing high economic losses in aquaculture. Epithelial cells in mucosal organs are target sites for VHSV entry into fish. To protect fish against VHSV infection, there is a need to develop antiviral compounds able to prevent establishment of infection at portals of virus entry into fish. Bacillus subtilis is a probiotic with excellent antiviral properties, of which one of its secretions, surfactin, has been shown to inhibit viral infections in mammals. Herein, we demonstrate its ability to prevent VHSV infection in olive flounder (Paralichthys olivaceus) intestinal epithelial cells (IECs) and infection in internal organs. Our findings show inhibition of VHSV infection in IECs by B. subtilis and surfactin. In addition, our findings showed inhibition of VHSV in Epithelioma Papulosum Cyprini (EPC) cells inoculated with intestinal homogenates from the fish pretreated with B. subtilis by oral exposure, while the untreated fish had cytopathic effects (CPE) caused by VHSV infection in the intestines at 48 h after the VHSV challenge. At 96 h post-challenge, samples from the untreated fish had CPE from head kidney and spleen homogenates and no CPE were observed in the intestinal homogenates, while the B. subtilis-pretreated fish had no CPE in all organs. These findings demonstrate that inhibition of VHSV infection at portals of virus entry in the intestines culminated in prevention of infection in internal organs. In summary, our results show that B. subtilis has the potential to prevent VHSV infection in fish and that its use as a probiotic in aquaculture has the potential to serve as an antiviral therapeutic agent against different viral infections.


Assuntos
Antibiose , Bacillus subtilis/fisiologia , Células Epiteliais/virologia , Doenças dos Peixes/virologia , Linguado/virologia , Mucosa Intestinal/virologia , Infecções por Rhabdoviridae/veterinária , Animais , Células Cultivadas , Novirhabdovirus
19.
Mar Drugs ; 18(12)2020 Dec 17.
Artigo em Inglês | MEDLINE | ID: mdl-33348729

RESUMO

Edwardsiella tarda can cause fatal gastro-/extraintestinal diseases in fish and humans. Overuse of antibiotics has led to antibiotic resistance and contamination in the environment, which highlights the need to find new antimicrobial agents. In this study, the marine peptide-N6 was amidated at its C-terminus to generate N6NH2. The antibacterial activity of N6 and N6NH2 against E. tarda was evaluated in vitro and in vivo; their stability, toxicity and mode of action were also determined. Minimal inhibitory concentrations (MICs) of N6 and N6NH2 against E. tarda were 1.29-3.2 µM. Both N6 and N6NH2 killed bacteria by destroying the cell membrane of E. tarda and binding to lipopolysaccharide (LPS) and genomic DNA. In contrast with N6, N6NH2 improved the stability toward trypsin, reduced hemolysis (by 0.19% at a concentration of 256 µg/mL) and enhanced the ability to penetrate the bacterial outer and inner membrane. In the model of fish peritonitis caused by E. tarda, superior to norfloxacin, N6NH2 improved the survival rate of fish, reduced the bacterial load on the organs, alleviated the organ injury and regulated the immunity of the liver and kidney. These data suggest that the marine peptide N6NH2 may be a candidate for novel antimicrobial agents against E. tarda infections.


Assuntos
Antibacterianos/farmacologia , Peptídeos Catiônicos Antimicrobianos/farmacologia , Edwardsiella tarda/efeitos dos fármacos , Infecções por Enterobacteriaceae/tratamento farmacológico , Infecções por Enterobacteriaceae/virologia , Doenças dos Peixes/tratamento farmacológico , Animais , Antibacterianos/química , Peptídeos Catiônicos Antimicrobianos/química , Membrana Celular/efeitos dos fármacos , Infecções por Enterobacteriaceae/microbiologia , Doenças dos Peixes/microbiologia , Doenças dos Peixes/patologia , Proteínas de Peixes , Rim/patologia , Fígado/patologia , Testes de Sensibilidade Microbiana , Norfloxacino/uso terapêutico , Peritonite/tratamento farmacológico , Peritonite/etiologia , Relação Estrutura-Atividade , Análise de Sobrevida
20.
Dis Aquat Organ ; 141: 195-224, 2020 Nov 05.
Artigo em Inglês | MEDLINE | ID: mdl-33150869

RESUMO

Recent surveys of white perch Morone americana from Chesapeake Bay, USA, revealed a high prevalence of hepatic and biliary lesions, including neoplasia, and bile duct parasites. Here, we describe lesions in the liver and gallbladder and evaluate for statistical associations among lesions, parasites, and biomarkers of chemical exposure in fish from 2 tributaries of Chesapeake Bay. Fish were collected from an estuarine site in the Choptank River (n = 122, ages 3-11), a tributary with extensive agriculture within the watershed, and the Severn River (n = 131, ages 2-16), a tributary with extensive urban development. Passive integrative samplers were deployed at the fish collection site and an upstream, non-tidal site in each river for 30 d. Intrahepatic biliary lesions observed in fish from both rivers included neoplasia (23.3%), dysplasia (16.2%), hyperplasia (46.6%), cholangitis (24.9%), and dilated ducts containing plasmodia of Myxidium sp. (24.9%). Hepatocellular lesions included foci of hepatocellular alteration (FHA, 15.8%) and neoplasia in 4 Severn River fish (2.3%). Age of fish and Myxidium sp. infections were significant risk factors for proliferative and neoplastic biliary lesions, age alone was a risk factor for FHA, and Goussia bayae infections were associated with cholangitis and cholecystitis. Lesion prevalence was higher in fish from the Severn River, which contained higher concentrations of PAHs, organochlorine pesticides, and brominated diphenyl ethers. Metabolite biomarkers indicated higher PAH exposures in Severn River fish. This study suggests Myxidium sp. as a promoter of bile duct tumors, but more data are needed to evaluate the biological effects of environmental contaminants in this species.


Assuntos
Bass , Doenças dos Peixes , Neoplasias , Parasitos , Poluentes Químicos da Água , Animais , Ductos Biliares , Monitoramento Ambiental , Doenças dos Peixes/epidemiologia , Neoplasias/veterinária , Prevalência
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