Eel herpesvirus or anguillid herpesvirus 1 (AngHV1) frequently causes disease in freshwater eels. The complete genome sequence of AngHV1 and its taxonomic position within the family Alloherpesviridae ...were determined. Shotgun sequencing revealed a 249 kbp genome including an 11 kbp terminal direct repeat that contains 7 of the 136 predicted protein-coding open reading frames. Twelve of these genes are conserved among other members of the family Alloherpesviridae and another 28 genes have clear homologues in cyprinid herpesvirus 3. Phylogenetic analyses based on amino acid sequences of five conserved genes, including the ATPase subunit of the terminase, confirm the position of AngHV1 within the family Alloherpesviridae, where it is most closely related to the cyprinid herpesviruses. Our analyses support a recent proposal to subdivide the family Alloherpesviridae into two sister clades, one containing AngHV1 and the cyprinid herpesviruses and the other containing Ictalurid herpesvirus 1 and the ranid herpesviruses.
As aquaculture production and the consumption of aquaculture products increase, the possibility of contracting zoonotic infections from either handling or ingesting these products also increases. The ...principal pathogens acquired topically from fish or shellfish through spine/pincer puncture or open wounds are Aeromonas hydrophila, Edwardsiella tarda, Mycobacterium marinum, Streptococcus iniae, Vibrio vulnificus and V. damsela. These pathogens, which are all indigenous to the aquatic environment, have also been associated with disease outbreaks in food fish. Outbreaks are often related to management factors, such as the quality and quantity of nutrients in the water and high stocking density, which can increase bacterial loads on the external surface of the fish. As a result, diseased fish are more likely to transmit infection to humans. This review provides an account of human cases of zoonoses throughout the world from the principal zoonotic pathogens of fish and shellfish.
Vibrio vulnificus is a potentially zoonotic bacterial pathogen of fish, which can infect humans (causing necrotic fasciitis). We analysed 24 V. vulnificus isolates (from 23 severe eel disease ...outbreaks in 8 Dutch eel farms during 1996 to 2009, and 1 clinical strain from an eel farmer) for genetic correlation and zoonotic potential. Strains were typed using biotyping and molecular typing by high-throughput multilocus sequence typing (hiMLST) and REP-PCR (Diversilab®). We identified 19 strains of biotype 1 and 5 of biotype 2 (4 from eels, 1 from the eel farmer), that were subdivided into 8 MLST types (ST) according to the international standard method. This is the first report of V. vulnificus biotype 1 outbreaks in Dutch eel farms. Seven of the 8 STs, of unknown zoonotic potential, were newly identified and were deposited in the MLST database. The REP-PCR and the MLST were highly concordant, indicating that the REP-PCR is a useful alternative for MLST. The strains isolated from the farmer and his eels were ST 112, a known potential zoonotic strain. Antimicrobial resistance to cefoxitin was found in most of the V. vulnificus strains, and an increasing resistance to quinolones, trimethoprim + sulphonamide and tetracycline was found over time in strain ST 140. Virulence testing of isolates from diseased eels is recommended, and medical practitioners should be informed about the potential risk of zoonotic infections by V. vulnificus from eels for the prevention of infection especially among high-risk individuals. Additional use of molecular typing methods such as hiMLST and Diversilab® is recommended for epidemiological purposes during V. vulnificus outbreaks.
The worldwide decline of the eel population is thought to be caused by several factors, among which eel diseases. To investigate diseases of European silver eels
Anguilla anguilla in the Netherlands, ...in Nov–Dec 2004 12 silver eels, and in Aug–Dec 2005 80 eels were caught in downstream parts (rivers) of the River Rhine and in Lake IJsselmeer. The eels were measured and weighed, necrotized, and individually checked for presence of external and internal parasites, bacterial infections and viruses, and blood smears were made for haematology. This is the first multidisciplinary study of the health of Dutch silver eels. In the small (2
×
6 eels) pilot study of 2004 in the River Rhine and Lake IJsselmeer respectively, most eels showed aspecific fin haemorrhages, some had ectoparasites, nearly none had parasites in the intestine, half of the groups had
Anguillicola crassus in their swimbladder, only few had
Trypanosoma's in their blood, and no primary virus or bacterial infections were found, although one eel from Lake IJsselmeer was positive for anguillid herpesvirus 1 (AngHV-1, former Herpesvirus anguillae, HVA) in the PCR test only. The blood of all 6 and 2/6 of the eels respectively was considered abnormal, and the eels had a proper condition.
In 2005, in 50 eels from the River Rhine and 30 from Lake IJsselmeer respectively, again aspecific fin haemorrhages were often seen, some of the eels had ectoparasites and parasites in the intestine, most eels had
A. crassus in their swimbladder, 32% and 53% had
Trypanosoma's in their blood, from 44% and 13% of the eels AngHV-1 was isolated, and 44% and 27% were tested positive by PCR, with a peak in August, 10% of both groups of eels had an internal bacterial infection, mostly due to
Aeromonas spp. The blood of about half of the eels was considered abnormal, but the eels had a proper condition.
It was concluded, that the silver eels of this study had a proper Fulton condition factor (values 2.00–2.26), with aspecific fin haemorrhages, often were
Trypanosoma-,
A. crassus- and AngHV-1-infected, dependent on the season, and often showed an abnormal haematology.
A. crassus causes injuries and is a chronic stress factor, more than the other parasites, which were mostly found less prevalent. In fact, lymphocytosis was directly related to
A. crassus infection. Stress and injuries by
A. crassus might induce disease through the presence of virus (AngHV-1), relevant in the health status of the silver eels during their spawning migration if ambient water temperatures would enhance a clinical infection of AngHV-1 disease. Moreover this virus might potentially decrease the survival of the silver eels by itself, because spawning migration to the Sargasso Sea takes wild eels to temperate/tropical areas in which the clinical infection by AngHV-1 is surely enhanced.
Summary Background In The Netherlands, efforts to control meticillin-resistant Staphylococcus aureus (MRSA) in hospitals have been largely successful due to stringent screening of patients on ...admission and isolation of those that fall into defined risk categories. However, Dutch hospitals are not free of MRSA, and a considerable number of cases are found that do not belong to any of the risk categories. Some of these may be due to undetected nosocomial transmission, whereas others may be introduced from unknown reservoirs. Aim Identifying multi-institutional clusters of MRSA isolates to estimate the contribution of potential unobserved reservoirs in The Netherlands. Methods We applied a clustering algorithm that combines time, place, and genetics to routine data available for all MRSA isolates submitted to the Dutch Staphylococcal Reference Laboratory between 2008 and 2011 in order to map the geo-temporal distribution of MRSA clonal lineages in The Netherlands. Findings Of the 2966 isolates lacking obvious risk factors, 579 were part of geo-temporal clusters, whereas 2387 were classified as MRSA of unknown origin (MUOs). We also observed marked differences in the proportion of isolates that belonged to geo-temporal clusters between specific multi-locus variable number of tandem repeat analysis (MLVA) clonal complexes, indicating lineage-specific transmissibility. The majority of clustered isolates (74%) were present in multi-institutional clusters. Conclusion The frequency of MRSA of unknown origin among patients lacking obvious risk factors is an indication of a largely undefined extra-institutional but genetically highly diverse reservoir. Efforts to understand the emergence and spread of high-risk clones require the pooling of routine epidemiological information and typing data into central databases.
Many of the known fish herpesviruses have important aquaculture species as their natural host, and may cause serious disease and mortality. Anguillid herpesvirus 1 (AngHV-1) causes a hemorrhagic ...disease in European eel, Anguilla anguilla. Despite their importance, fundamental molecular knowledge on fish herpesviruses is still limited. In this study we describe the identification and localization of the structural proteins of AngHV-1. Purified virions were fractionated into a capsid-tegument and an envelope fraction, and premature capsids were isolated from infected cells. Proteins were extracted by different methods and identified by mass spectrometry. A total of 40 structural proteins were identified, of which 7 could be assigned to the capsid, 11 to the envelope, and 22 to the tegument. The identification and localization of these proteins allowed functional predictions. Our findings include the identification of the putative capsid triplex protein 1, the predominant tegument protein, and the major antigenic envelope proteins. Eighteen of the 40 AngHV-1 structural proteins had sequence homologues in related Cyprinid herpesvirus 3 (CyHV-3). Conservation of fish herpesvirus structural genes seemed to be high for the capsid proteins, limited for the tegument proteins, and low for the envelope proteins. The identification and localization of the structural proteins of AngHV-1 in this study adds to the fundamental knowledge of members of the Alloherpesviridae family, especially of the Cyprinivirus genus.
In spring 2008, infectious hematopoietic necrosis virus (IHNV) was detected for the first time in the Netherlands. The virus was isolated from rainbow trout, Oncorhynchus mykiss (Walbaum), from a ...put‐and‐take fishery with angling ponds. IHNV is the causative agent of a serious fish disease, infectious hematopoietic necrosis (IHN). From 2008 to 2011, we diagnosed eight IHNV infections in rainbow trout originating from six put‐and‐take fisheries (symptomatic and asymptomatic fish), and four IHNV infections from three rainbow trout farms (of which two were co‐infected by infectious pancreatic necrosis virus, IPNV), at water temperatures between 5 and 15 °C. At least one farm delivered trout to four of these eight IHNV‐positive farms. Mortalities related to IHNV were mostly <40%, but increased to nearly 100% in case of IHNV and IPNV co‐infection. Subsequent phylogenetic analysis revealed that these 12 isolates clustered into two different monophyletic groups within the European IHNV genogroup E. One of these two groups indicates a virus‐introduction event by a German trout import, whereas the second group indicates that IHNV was already (several years) in the Netherlands before its discovery in 2008.
Anguillid herpesvirus 1 (AngHV1) causes a haemorrhagic disease with increased mortality in wild and farmed European eel, Anguilla anguilla (L.) and Japanese eel Anguilla japonica, Temminck & ...Schlegel). Detection of AngHV1 is currently based on virus isolation in cell culture, antibody‐based typing assays or conventional PCR. We developed, optimized and concisely validated a diagnostic TaqMan probe based real‐time PCR assay for the detection of AngHV1. The primers and probe target AngHV1 open reading frame 57, encoding the capsid protease and scaffold protein. Compared to conventional PCR, the developed real‐time PCR is faster, less labour‐intensive and has a reduced risk of cross‐contamination. The real‐time PCR assay was shown to be analytically sensitive and specific and has a high repeatability, efficiency and r2‐value. The diagnostic performance of the assay was determined by testing 10% w/v organ suspensions and virus cultures from wild and farmed European eels from the Netherlands by conventional and real‐time PCR. The developed real‐time PCR assay is a useful tool for the rapid and sensitive detection of AngHV1 in 10% w/v organ suspensions from wild and farmed European eels.
Nanocrystalline diamond (NCD) is a promising material for electronic and mechanical micro- and nanodevices. Here we introduce a versatile pick-up and drop technique that makes it possible to ...investigate the electrical, optical and mechanical properties of as-grown NCD films. Using this technique, NCD nanosheets, as thin as 55 nm, can be picked-up from a growth substrate and positioned on another substrate. As a proof of concept, electronic devices and mechanical resonators are fabricated and their properties are characterized. In addition, the versatility of the method is further explored by transferring NCD nanosheets onto an optical fiber, which allows measuring its optical absorption. Finally, we show that NCD nanosheets can also be transferred onto two-dimensional crystals, such as MoS2, to fabricate heterostructures. Pick-up and drop transfer enables the fabrication of a variety of NCD-based devices without requiring lithography or wet processing.
Eight outbreaks of “red spot disease” were diagnosed between March and June 1997 in diseased European elvers
Anguilla anguilla (L.), maintained at 23–25°C in The Netherlands. The elvers originated ...from Southwestern France and Northern Portugal. In all cases,
Pseudomonas anguilliseptica was isolated in pure culture. The mortalities varied from 3% to 20%, within 2–3 weeks of the initial outbreak. The isolates were phenotypically similar to French isolates from sea bream
Sparus aurata (L.), sea bass
Dicentrarchus labrax (L.) and turbot
Scophthalmus maximus (L.). They were sensitive to neomycine, trimethoprim, trimethoprim+sulphadiazine, and sulphonamids, and some were sensitive to oxytetracycline, flumequine, and oxolinic acid. Mortality ceased when the water temperature was raised to 26–27°C. One isolate was tested for pathogenicity by experimental infection in post elvers and larger European eels, and showed low pathogenicity.
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