Staff Publications

Staff Publications

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    'Staff publications' is the digital repository of Wageningen University & Research

    'Staff publications' contains references to publications authored by Wageningen University staff from 1976 onward.

    Publications authored by the staff of the Research Institutes are available from 1995 onwards.

    Full text documents are added when available. The database is updated daily and currently holds about 240,000 items, of which 72,000 in open access.

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    Responses of a tropical micro-crustacean, Daphnia lumholtzi, upon exposures to dissolved toxins and living cells of cyanobacteria
    Vo, Thi My Chi ; Bui, Ba Trung ; Wiegand, Claudia ; Dinh, Khuong V. ; Dao, Thanh Son - \ 2020
    Environmental Technology and Innovation 19 (2020). - ISSN 2352-1864
    Acute lethal concentration - Clutch size - Cylindrospermopsis curvispora - Microcystins - Reproduction - Survival proportion

    The mass development and expansion of cyanobacteria release cyanotoxins in the aquatic environment and cause serious problems for grazers such as micro-zooplankton. In contrast to aquatic ecosystems in temperate regions, impacts of cyanobacteria and their toxins on tropical micro-crustaceans are relatively understudied. In this study, acute and chronic effects of pure microcystin-LR (MC-LR), a crude extract of water bloom sample with a dominance of Microcystis aeruginosa containing microcystins (MCE) and living cells of Cylindrospermopsis curvispora were tested on a tropical micro-crustacean, Daphnia lumholtzi. The 24 h- and 48 h-LC50 values for MC-LR ranged from 247–299, and 331–409 μg MCE L−1, respectively. Exposures to 1–25 μg MCE L−1 decreased survival, fecundity, and reproduction of D. lumholtzi. The impacts of C. curvispora cells on life-history traits of D. lumholtzi were density-dependent and more severe than the impacts of dissolved microcystins. It could be that the adverse effects of C. curvispora on D. lumholtzi are linked to a combination of potential toxic metabolites, mal-nutrients, feeding and swimming interference. Daphnia lumholtzi used in this study is more sensitive to microcystins compared to Daphnia species from temperate regions. Therefore, we highly suggest using D. lumholtzi as a model species for toxicity testing and monitoring on water quality, particularly in tropical countries.

    Influence of changes in socioeconomic and climatic conditions on future heat-related health challenges in Europe
    Rohat, Guillaume ; Flacke, Johannes ; Dosio, Alessandro ; Pedde, Simona ; Dao, Hy ; Maarseveen, Martin van - \ 2019
    Global and Planetary Change 172 (2019). - ISSN 0921-8181 - p. 45 - 59.
    Climate Change - Europe - Health risk - Heat stress - Shared Socioeconomic Pathways - Vulnerability

    The majority of assessments of future heat-related health risk are based on projections of heat hazards superimposed solely on current socioeconomic conditions, thus neglecting the potential contribution of drivers of heat stress risk other than climate change. Partly to address this drawback, the climate change research community has developed a new scenario framework, made up of distinct sets of climate and socioeconomic scenarios. The few assessments of future heat-related health risk that have employed this new framework have focused on changes in population exposure but have often not accounted for future populations' vulnerability. In this paper, we combine European Shared Socioeconomic Pathways with Representative Concentration Pathways to provide spatially explicit European projections of heat-related health risk that account for multiple changes in both socioeconomic and climatic conditions. In doing so, we also address the challenge of accounting for projections of determinants of vulnerability under varying levels of socioeconomic development. Results reveal that the proportion of the European population at very high risk of heat stress will show a steady increase – from 0.4% currently to 20.3%, 32.6%, or 48.4% in 2050 depending on the scenario combination – unless substantial political changes occur rapidly and steadily shift the current socioeconomic development pathway towards sustainability. Ambitious mitigation policies associated with rapid technological progress to enhance human capital could also moderate future heat-related health challenges. Such challenges are unevenly spread across Europe, with the Mediterranean region and Scandinavia being respectively the most and the least impacted regions. Future heat-related health challenges are substantially influenced by varying levels of socioeconomic development, primarily through changes in vulnerability – changes in population exposure being only of secondary importance. The former may even have a more significant impact on future heat stress risk than climate change, particularly in the British Isles and in the Iberian Peninsula. Thus, there is an undeniable necessity to consider the future state of vulnerability – and its uncertainties under varying socioeconomic scenarios – when assessing future heat-related health challenges and designing health adaptation strategies.

    Cyanobacterial Blooms and Microcystins in Southern Vietnam
    Trung, Bui ; Dao, Thanh Son ; Faassen, Els ; Lürling, Miquel - \ 2018
    Toxins 10 (2018)11. - ISSN 2072-6651
    aquaculture - cyanobacteria - cyanotoxins - Mekong river

    Studies on cyanobacteria in Vietnam are limited and mainly restricted to large reservoirs. Cyanobacterial blooms in small water bodies may pose a health risk to local people. We sampled 17 water bodies in the vicinity of urban settlements throughout the Mekong basin and in southeast Vietnam. From these, 40 water samples were taken, 24 cyanobacterial strains were isolated and 129 fish, 68 snail, 7 shrimp, 4 clam, and 4 duck samples were analyzed for microcystins (MCs). MCs were detected up to 11,039 µg/L or to 4033 µg/g DW in water samples. MCs were detected in the viscera of the animals. MC-LR and MC-RR were most frequently detected, while MC-dmLR, MC-LW, and MC-LF were first recorded in Vietnam. Microcystis was the main potential toxin producer and the most common bloom-forming species. A potential health hazard was found in a duck⁻fish pond located in the catchment of DauTieng reservoir and in the DongNai river where raw water was collected for DongNai waterwork. The whole viscera of fish and snails must be completely removed during food processing. Cyanobacterial monitoring programs should be established to assess and minimize potential public health risks.

    Transgenerational effects of cyanobacterial toxins on a tropical micro-crustacean Daphnia lumholtzi across three generations
    Dao, Thanh-Son ; Vo, Thi-My-Chi ; Wiegand, Claudia ; Bui, Ba-Trung ; Dinh, Khuong V. - \ 2018
    Environmental Pollution 243 (2018). - ISSN 0269-7491 - p. 791 - 799.
    Adaptation - Life history traits - Microcystins - Tolerance - Zooplankton

    Climate change and human activities induce an increased frequency and intensity of cyanobacterial blooms which could release toxins to aquatic ecosystems. Zooplankton communities belong to the first affected organisms, but in tropical freshwater ecosystems, this issue has yet been poorly investigated. We tested two questions (i) if the tropical Daphnia lumholtzi is capable to develop tolerance to an ecologically relevant concentration of purified microcystin-LR and microcystins from cyanobacterial extract transferable to F1 and F2 generations? And (ii) would F1 and F2 generations recover if reared in toxin-free medium? To answer these questions, we conducted two full factorial mutigenerational experiments, in which D. lumholtzi was exposed to MC-LR and cyanobacterial extract at the concentration of 1 μg L−1 microcystin continuously for three generations. After each generation, each treatment was spit into two: one reared in the control (toxin free) while the other continued in the respective exposure. Fitness-related traits including survival, maturity age, body length, and fecundity of each D. lumholtzi generation were quantified. Though there were only some weak negative effects of the toxins on the first generation (F0), we found strong direct, accumulated and carried-over impacts of the toxins on life history traits of D. lumholtzi on the F1 and F2, including reductions of survival, and reproduction. The maturity age and body length showed some inconsistent patterns between generations and need further investigations. The survival, maturity age (for extract), and body length (for MC-LR) were only recovered when offspring from toxin exposed mothers were raised in clean medium for two generations. Chronic exposure to long lasting blooms, even at low density, evidently reduces survival of D. lumholtzi in tropical lakes and reservoirs with ecological consequences. Exposure to environmentally relevant concentrations of cyanobacterial toxins for 3 generations tropical Daphnia lumholtzi developed no or marginal tolerance.

    Priorities for protected area research
    Dudley, Nigel ; Hockings, Marc ; Stolton, Sue ; Amend, Thora ; Badola, Ruchi ; Bianco, Mariasole ; Chettri, Nakul ; Cook, Carly ; Day, Jon C. ; Dearden, Phil ; Edwards, Mary ; Ferraro, Paul ; Foden, Wendy ; Gambino, Roberto ; Gaston, Kevin J. ; Hayward, Natalie ; Hickey, Valerie ; Irving, Jason ; Jeffries, Bruce ; Karapetyan, Areg ; Kettunen, Marianne ; Laestadius, Lars ; Laffoley, Dan ; Lham, Dechen ; Lichtenstein, Gabriela ; Makombo, John ; Marshall, Nina ; McGeoch, Melodie ; Nguyen, Dao ; Nogué, Sandra ; Paxton, Midori ; Rao, Madhu ; Reichelt, Russell ; Rivas, Jorge ; Roux, Dirk ; Rutte, Claudia ; Schreckenberg, Kate ; Sovinc, Andrej ; Sutyrina, Svetlana ; Utomo, Agus ; Vallauri, Daniel ; Vedeld, Pål Olav ; Verschuuren, Bas ; Waithaka, John ; Woodley, Stephen ; Wyborn, Carina ; Zhang, Yan - \ 2018
    PARKS: the International of Protected Areas and Conservation 24 (2018)1. - ISSN 0960-233X - p. 35 - 50.
    Managers - Protected areas - Research priorities - Researchers - Stakeholder assessment

    A hundred research priorities of critical importance to protected area management were identified by a targeted survey of conservation professionals; half researchers and half practitioners. Respondents were selected to represent a range of disciplines, every continent except Antarctica and roughly equal numbers of men and women. The results analysed thematically and grouped as potential research topics as by both practitioners and researchers. Priority research gaps reveal a high interest to demonstrate the role of protected areas within a broader discussion about sustainable futures and if and how protected areas can address a range of conservation and socio-economic challenges effectively. The paper lists the hundred priorities structured under broad headings of management, ecology, governance and social (including political and economic issues) and helps contribute to setting future research agendas.

    Warming affects growth rates and microcystin production in tropical bloom-forming microcystis strains
    Bui, Trung ; Dao, Thanh Son ; Vo, Truong Giang ; Lürling, Miquel - \ 2018
    Toxins 10 (2018)3. - ISSN 2072-6651
    Cell quota - Climate change - Cyanobacterial blooms - Cyanotoxins - Mekong delta - Vietnam
    Warming climate is predicted to promote cyanobacterial blooms but the toxicity of cyanobacteria under global warming is less well studied. We tested the hypothesis that raising temperature may lead to increased growth rates but to decreased microcystin (MC) production in tropical Microcystis strains. To this end, six Microcystis strains were isolated from different water bodies in Southern Vietnam. They were grown in triplicate at 27◦C (low), 31◦C (medium), 35◦C (high) and 37◦C (extreme). Chlorophyll-a-, particle- and MC concentrations as well as dry-weights were determined. All strains yielded higher biomass in terms of chlorophyll-a concentration and dry-weight at 31◦C compared to 27◦C and then either stabilised, slightly increased or declined with higher temperature. Five strains easily grew at 37◦C but one could not survive at 37◦C. When temperature was increased from 27◦C to 37◦C total MC concentration decreased by 35% in strains with MC-LR as the dominant variant and by 94% in strains with MC-RR. MC quota expressed per particle, per unit chlorophyll-a and per unit dry-weight significantly declined with higher temperatures. This study shows that warming can prompt the growth of some tropical Microcystis strains but that these strains become less toxic.
    Interplay between land-use dynamics and changes in hydrological regime in the Vietnamese Mekong Delta
    Le, Thuy Ngan ; Bregt, Arnold K. ; Halsema, Gerardo E. van; Hellegers, Petra J.G.J. ; Nguyen, Lam-Dao - \ 2018
    Land Use Policy 73 (2018). - ISSN 0264-8377 - p. 269 - 280.
    Policies supporting rice production and investments in water infrastructure enabled intensification and diversification of farming systems in the Vietnamese Mekong Delta (VMD) over the past 20 years. Yet, demands of food security, economic development, and climate change continue to pose diverging and often conflicting challenges for water resources management in the upper, central, and coastal zones of the delta. The major changes effected in the VMD’s hydrological regime and land-use patterns are acknowledged in the literature, but few studies have examined the interplay between these dynamics at the delta scale. Based on time-series maps and statistical data on land-use, flooding, and salinity intrusion, we investigated the interrelations between land-use dynamics and changes in hydrological regime across the VMD in three representative periods. Land-use was found to be highly variable, changing by 14.94% annually between 2001 and 2012. Rice cropping underwent the greatest change, evolving from single cropping of traditional varieties towards double and triple cropping of high-yielding varieties. Aquaculture remained stable after rapid expansion in the 1990s and early 2000s. Meanwhile, flooding and salinity intrusion were increasingly controlled by hydrological infrastructure erected to supply freshwater for agriculture. Effects of this infrastructure became particularly evident from 2001 to 2012. During this period, spatial and temporal impacts on flooding and salinity intrusion were found, which extended beyond the rice fields to affect adjacent lands and livelihood activities. Unforeseen effects will likely be aggravated by climate change, suggesting a need to rethink the scale of planning towards a more integrated hydrologic approach.
    Emergence of carp edema virus (CEV) and its significance to European common carp and koi Cyprinus carpio
    Way, K. ; Haenen, O. ; Stone, D. ; Adamek, M. ; Bergmann, S.M. ; Bigarré, L. ; Diserens, Nicolas ; El-Matbouli, M. ; Gjessing, M.C. ; Jung-Schroers, V. ; Leguay, E. ; Matras, M. ; Olesen, Niels J. ; Panzarin, Valentina ; Piačková, V. ; Toffan, A. ; Vendramin, N. ; Veselý, T. ; Waltzek, T. - \ 2017
    Diseases of Aquatic Organisms 126 (2017)2. - ISSN 0177-5103 - p. 155 - 166.
    Aquaculture - CEVD - Cyprinus carpio - Koi sleepy disease - PCR - Poxvirus
    Carp edema virus disease (CEVD), also known as koi sleepy disease, is caused by a poxvirus associated with outbreaks of clinical disease in koi and common carp Cyprinus carpio. Originally characterised in Japan in the 1970s, international trade in koi has led to the spread of CEV, although the first recognised outbreak of the disease outside of Japan was not reported until 1996 in the USA. In Europe, the disease was first recognised in 2009 and, as detection and diagnosis have improved, more EU member states have reported CEV associated with disease outbreaks. Although the structure of the CEV genome is not yet elucidated, molecular epidemiology studies have suggested distinct geographical populations of CEV infecting both koi and common carp. Detection and identification of cases of CEVD in common carp were unreliable using the original PCR primers. New primers for conventional and quantitative PCR (qPCR) have been designed that improve detection, and their sequences are provided in this paper. The qPCR primers have successfully detected CEV DNA in archive material from investigations of unexplained carp mortalities conducted >15 yr ago. Improvement in disease management and control is possible, and the principles of biosecurity, good health management and disease surveillance, applied to koi herpesvirus disease, can be equally applied to CEVD. However, further research studies are needed to fill the knowledge gaps in the disease pathogenesis and epidemiology that, currently, prevent an accurate assessment of the likely impact of CEVD on European koi and common carp aquaculture and on wild carp stocks.
    Importation of CyHV-2-infected goldfish into the Netherlands
    Ito, Takafumi ; Kurita, Jun ; Haenen, Olga L.M. - \ 2017
    Diseases of Aquatic Organisms 126 (2017). - ISSN 0177-5103 - p. 51 - 62.
    Cyprinid herpesvirus 2 - Disease spread - Genotype - Goldfish - International trade - Ornamental fish - Risk factor

    Cyprinid herpesvirus 2 (CyHV-2) is known as the causative agent of herpesviral haematopoietic necrosis in goldfish Carassius auratus auratus. However, the virus has also been detected in Prussian carp C. gibelio and crucian carp C. carassius from European and Asian countries. To prevent spread of the causative virus to other areas, investigation of the risk factors of spread of this virus is important. In this study, 8 batches of goldfish imported into the Netherlands by airfreight from Asia and the Middle East were investigated for the presence of the virus. CyHV- 2 DNA was detected by PCR in the pooled kidneys of 4 of the 8 imported goldfish batches, of which 1 was from a CyHV-2 disease case at a Dutch importer's quarantine facility. Sequence analysis of the CyHV-2 strains from this study and from previous reports showed that there were at least 6 different lengths in the mA region, resulting in tentatively at least 4 genotypes. Virus isolation was positive for only 1 (Amsterdam Schiphol-1 [AMS-1]) of the 8 samples. It was shown that the AMS-1 isolate was highly virulent to Ryukin goldfish after 100.3 TCID50 fish-1 intraperitoneal injection. The viral titre of the AMS-1 isolate for goldfish fin cells at several temperatures was similar to that of a Japanese CyHV-2 isolate. Our results prove that one of the routes of spread of various CyHV-2 strains is through the global trade of apparently healthy infected goldfish.

    An evaluation of fish health-management practices and occupational health hazards associated with Pangasius catfish (Pangasianodon hypophthalmus) aquaculture in the Mekong Delta, Vietnam
    Phu, Tran Minh ; Phuong, Nguyen Thanh ; Dung, Tu Thanh ; Hai, Dao Minh ; Son, Vo Nam ; Rico Artero, Andreu ; Clausen, Jesper Hedegaard ; Madsen, Henry ; Murray, Francis ; Dalsgaard, Anders - \ 2016
    Aquaculture Research 47 (2016)9. - ISSN 1355-557X - p. 2778 - 2794.
    Pangasianodon hypophthalmus - Antimicrobials - Catfish - Fish disease - Mekong Delta - Occupational health

    This study aimed to evaluate the current status on the use of probiotics, disinfectants and antimicrobials in hatcheries, nurseries and grow-out farms producing Pangasius catfish (Pangasianodon hypophthalmus) in the Mekong Delta, Vietnam. Semi-structured interviews were conducted with 83 aquaculture enterprises (15 hatcheries, 32 nurseries and 36 grow-out farms). Farmers reported use of a total of 24 different antimicrobials, e.g. for treatment of bacillary necrosis and motile aeromonad septicaemia, and a variety of disinfectants, probiotics and nutritional supplements. In contrast to small-scale farmers, all large-scale grow-out farmers studied were certified and therefore had higher levels of formal education and specialized aquaculture training to diagnose and treat diseases. All farmers prepared their own medicated feed with a high risk of treatment failure, negative environmental impact from released antimicrobials and resistance development. Small-scale farmers were at particular occupational health risks when handling antimicrobials and other chemicals, e.g. mixing medicated feed with bare hands. There is an urgent need to improve knowledge and use innovative approaches, e.g. private-public partnerships, to assure a prudent use of chemicals, to improve capacity and access to disease diagnosis, particularly for small-scale grow-out farmers and nurseries. Efforts to control use of antimicrobials in aquaculture should be coordinated with the livestock and human health sectors taking an One-Health approach.

    Sesame DAO - Storing and retrieving semantic data in a structured manner
    Top, J.L. ; Willems, D.J.M. ; Batenburg, R.A. van - \ 2015
    Wageningen : Wageningen UR - Food & Biobased Research (Rapport / Wageningen UR Food & Biobased Research 1534) - ISBN 9789462573970 - 10 p.
    Bonamia parasites: a rapidly changing perspective on a genus of important mollusc pathogens
    Engelsma, M.Y. ; Culloty, S.C. ; Lynch, S.A. ; Arzul, I. ; Carnegie, R.B. - \ 2014
    Diseases of Aquatic Organisms 110 (2014)1-2. - ISSN 0177-5103 - p. 5 - 23.
    oyster ostrea-edulis - european flat oyster - crassostrea-gigas mollusca - n. sp haplosporidia - new-zealand - tiostrea-chilensis - protozoan parasite - mikrocytos-roughleyi - pacific oyster - pcr assay
    Organisms of the genus Bonamia are intracellular protistan parasites of oysters. To date, 4 species have been described (B. ostreae, B. exitiosa, B. perspora and B. roughleyi), although the status of B. roughleyi is controversial. Introduction especially of B. ostreae and B. exitiosa to naïve host populations has been shown to cause mass mortalities in the past and has had a dramatic impact on oyster production. Both B. ostreae and B. exitiosa are pathogens notifiable to the World Organisation for Animal Health (OIE) and the European Union. Effective management of the disease caused by these pathogens is complicated by the extensive nature of the oyster production process and limited options for disease control of the cultured stocks in open water. This review focuses on the recent advances in research on genetic relationships between Bonamia isolates, geographical distribution, susceptible host species, diagnostics, epizootiology, host-parasite interactions, and disease resistance and control of this globally important genus of oyster pathogens.
    Ultrastructural comparison of Bonamia spp (Haplosporidia) infecting ostreid oysters
    Hine, P.M. ; Carnegie, R.B. ; Kroeck, M.A. ; Villalba, A. ; Engelsma, M.Y. ; Burreson, E.M. - \ 2014
    Diseases of Aquatic Organisms 110 (2014)1. - ISSN 0177-5103 - p. 55 - 63.
    n. sp haplosporidia - flat oyster - tiostrea-chilensis - crassostrea-ariakensis - mikrocytos-roughleyi - new-zealand - edulis l - mytilus-galloprovincialis - north-carolina - parasite
    The ultrastructure of Bonamia from Ostrea angasi from Australia, Crassostrea ariakensis from the USA, O. puelchana from Argentina and O. edulis from Spain was compared with described Bonamia spp. All appear conspecific with B. exitiosa. The Bonamia sp. from Chile had similarities to the type B. exitiosa from New Zealand (NZ), but less so than the other forms recognized as B. exitiosa. Two groups of ultrastructural features were identified; those associated with metabolism (mitochondrial profiles, lipid droplets and endoplasmic reticulum), and those associated with haplosporogenesis (Golgi, indentations in the nuclear surface, the putative trans-Golgi network, perinuclear granular material and haplosporosome-like bodies). Metabolic features were regarded as having little taxonomic value, and as the process of haplosporogenesis is not understood, only haplosporosome shape and size may be of taxonomic value. However, the uni-nucleate stages of spore-forming haplosporidians are poorly known and may be confused with Bonamia spp. uni-nucleate stages. The many forms of NZ B. exitiosa have not been observed in other hosts, which may indicate that it has a plastic life cycle. Although there are similarities between NZ B. exitiosa and Chilean Bonamia in the development of a larger uni-nucleate stage and the occurrence of cylindrical confronting cisternae, the clarification of the identity of Chilean Bonamia must await molecular studies.
    Microcell parasites of molluscs: introduction to DAO special 7
    Carnegie, R.B. ; Engelsma, M.Y. - \ 2014
    Diseases of Aquatic Organisms 110 (2014)1-2. - ISSN 0177-5103 - p. 1 - 4.
    oyster ostrea-edulis - denman island disease - n. sp haplosporidia - mikrocytos-mackini - bonamia-ostreae - flat oyster - crassostrea-gigas - causative agent - pacific oysters - exitiosa
    First discovered decades ago, microcell protistan parasites of the genera Bonamia and Mikrocytos remain relevant today for their economic impacts on growing molluscan aquaculture industries and fisheries. Bonamia parasites have received more attention over the years in part because they are more widespread and thus of wider concern, but there has been renewed interest in Mikrocytos recently with the generation of important new findings. Among these has been the surprising observation that Mikrocytos has phylogenetic affinities to the Rhizaria, which includes the haplosporidian protists and the genus Bonamia. This Diseases of Aquatic Organisms Special, emerging from the 5th Meeting of the Microcell Working Group held at the Central Veterinary Institute, Lelystad, the Netherlands, in February 2012, presents new insights into Mikrocytos and Bonamia diversity, distributions, diagnostics, ultrastructure, and infection dynamics, and captures major developments in the field since the last review of these genera in 2004
    Vibrio vulnificus outbreaks in Dutch eel farms since 1996: strain diversity and impact.
    Haenen, O.L.M. ; Zanten, E. van; Jansen, R. ; Roozenburg, I. ; Engelsma, M.Y. ; Dijkstra, A. ; Boers, S.A. ; Voorbergen-Laarman, M. ; Möller, A.V.M. - \ 2014
    Diseases of Aquatic Organisms 108 (2014)3. - ISSN 0177-5103 - p. 201 - 209.
    diseased european eel - anguilla-anguilla - biotype 2 - clinical-manifestations - fresh-water - serovar-e - infection - pathogen - tilapia - fish
    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.
    Internal effect concentrations of organic substances for early life development of egg-exposed fish
    Foekema, E.M. ; Lopez Parron, M. ; Megia, M.T. ; Carolus, E.R.M. ; Berg, J.H.J. van den; Kwadijk, C.J.A.F. ; Dao, Q.T. ; Murk, A.J. - \ 2014
    Ecotoxicology and Environmental Safety 101 (2014). - ISSN 0147-6513 - p. 14 - 22.
    polybrominated diphenyl ethers - western scheldt estuary - zebrafish danio-rerio - flounder paralichthys-dentatus - trout salvelinus-fontinalis - toxic equivalency factors - medaka oryzias-latipes - southern north-sea - polychlorinated-biphenyls - hexabromocyclodo
    The present study investigates the likelihood that early life development of marine fish from contaminated areas is affected by maternally transferred persistent organic substances (POPs). The common sole (Solea solea) was used as model species. Fertilized eggs were exposed via the water until hatching, 6 days post fertilization. The newly hatched larvae were allowed to develop further under unexposed conditions until the end of the metamorphosis. Effects on the larvae were determined for the dioxin-like polychlorinated biphenyl PCB 126, the technical PCB-mixture Arochlor 1254, polybrominated diphenylethers (PBDEs), and hexabromocyclododecane (HBCD), for an artificial mixture of PCBs and PBDEs, and for ‘field mixtures’ extracted from sole from the North Sea and the contaminated Western Scheldt estuary. Effect levels were expressed as tissue concentrations in the newly hatched larvae at the end of the exposure period. Exposure to PCBs, PBDEs, and the artificial and field mixtures caused mortality that started to occur shortly after the larvae became free-feeding (10 days post fertilization) and continued to increase until the onset of metamorphosis, 15 days later. The effects induced by the field mixtures correlated well with the SPCB concentrations in the tissue of the exposed larvae. No indications were found for synergistic effects or for substantial contribution of other (unknown) substances in the field mixtures. HBCD did not induce toxic effects. As lipid normalized POP levels in fish eggs are in general comparable to the levels in the tissue of the female fish, fish tissue concentrations are indicative of the internal exposure of the developing larvae as a result maternally transferred POPs will occur in the field. In sole from the Western Scheldt estuary POP levels are about twenty times lower than the larval tissue concentration that produced 50 percent early life stage mortality. Levels in North Sea sole are an order of a magnitude lower. At more heavily contaminated sites negative effect of PCBs, especially of those with dioxin-like toxicity can be expected
    Detection of novel strains of cyprinid herpesvirus closely related to koi herpesvirus
    Engelsma, M.Y. ; Way, K. ; Dodge, M.J. ; Voorbergen-Laarman, H.A. ; Panzarin, V.M. ; Abbadi, M. ; El-Matbouli, M. ; Skall, H.F. ; Kahns, S. ; Stone, D.M. - \ 2013
    Diseases of Aquatic Organisms 107 (2013)2. - ISSN 0177-5103 - p. 113 - 120.
    common carp - thymidine kinase - 1st detection - genome - aquaculture - cloning - disease - khv
    Cyprinid herpesvirus 3 (CyHV-3) or koi herpesvirus (KHV) is a devastating virus of carp. Using generic primers for the DNA polymerase and the major capsid protein genes of cyprinid herpesviruses, nucleotide sequences divergent from previously described CyHV-3 were obtained. At least 3 novel groups of putative CyHV-3-like viruses were identified, sharing 95 to 98% nucleotide identity with CyHV-3 strains. Carp carrying the CyHV-3 variants did not show clinical signs consistent with CyHV-3 infection and originated from locations with no actual CyHV-3 outbreaks. These strains might represent low- or non-pathogenic variants of CyHV-3.
    Viral diseases of wild and farmed European eel Anguilla anguilla with particular reference to the Netherlands
    Beurden, S.J. van; Engelsma, M.Y. ; Roozenburg, I. ; Voorbergen-Laarman, H.A. ; Tulden, P.W. van; Kerkhoff, S. ; Nieuwstadt, A. ; Davidse, A. ; Haenen, O.L.M. - \ 2012
    Diseases of Aquatic Organisms 101 (2012). - ISSN 0177-5103 - p. 69 - 86.
    pancreatic necrosis virus - pillar cell necrosis - herpesvirus-anguillae - japanese eel - japonica temminck - phylogenetic-relationships - rhabdoviral dermatitis - taxonomic position - genome sequence - rainbow-trout
    Diseases are an important cause of losses and decreased production rates in freshwater eel farming, and have been suggested to play a contributory role in the worldwide decline in wild freshwater eel stocks. Three commonly detected pathogenic viruses of European eel Anguilla anguilla are the aquabirnavirus eel virus European (EVE), the rhabdovirus eel virus European X (EVEX), and the alloherpesvirus anguillid herpesvirus 1 (AngHV1). In general, all 3 viruses cause a nonspecific haemorrhagic disease with increased mortality rates. This review provides an overview of the current knowledge on the aetiology, prevalence, clinical signs and gross pathology of these 3 viruses. Reported experimental infections showed the temperature dependency and potential pathogenicity of these viruses for eels and other fish species. In addition to the published literature, an overview of the isolation of pathogenic viruses from wild and farmed A. anguilla in the Netherlands during the past 2 decades is given. A total of 249 wild A. anguilla, 39 batches of glass eels intended for farming purposes, and 239 batches of farmed European eels were necropsied and examined virologically. AngHV1 was isolated from wild A. anguilla yellow and silver eels from the Netherlands from 1998 until the present, while EVEX was only found sporadically, and EVE was never isolated. In farmed A. anguilla AngHV1 was also the most commonly isolated virus, followed by EVE and EVEX.
    Indel-II region deletion sizes in the white spot syndrome virus genome correlate with shrimp disease outbreaks in southern Vietnam
    Tran Thi Tuyet, H. ; Zwart, M.P. ; Phuong, N.T. ; Oanh, D.T.H. ; Jong, M.C.M. de; Vlak, J.M. - \ 2012
    Diseases of Aquatic Organisms 99 (2012)2. - ISSN 0177-5103 - p. 153 - 162.
    penaeus-monodon - bacilliform virus - genetic-variation - wssv - virulence - pathogenesis - thailand - sequence - province - fitness
    Sequence comparisons of the genomes of white spot syndrome virus (WSSV) strains have identified regions containing variable-length insertions/deletions (i.e. indels). Indel-I and Indel-II, positioned between open reading frames (ORFs) 14/15 and 23/24, respectively, are the largest and the most variable. Here we examined the nature of these 2 indel regions in 313 WSSV-infected Penaeus monodon shrimp collected between 2006 and 2009 from 76 aquaculture ponds in the Mekong Delta region of Vietnam. In the Indel-I region, 2 WSSV genotypes with deletions of either 5950 or 6031 bp in length compared with that of a reference strain from Thailand (WSSV-TH-96-II) were detected. In the Indel-II region, 4 WSSV genotypes with deletions of 8539, 10970, 11049 or 11866 bp in length compared with that of a reference strain from Taiwan (WSSV-TW) were detected, and the 8539 and 10970 bp genotypes predominated. Indel-II variants with longer deletions were found to correlate statistically with WSSV-diseased shrimp originating from more intensive farming systems. Like Indel-I lengths, Indel-II lengths also varied based on the Mekong Delta province from which farmed shrimp were collected
    Genome sequence of the pea aphid Acyrthosiphon pisum
    Richards, Stephen ; Gibbs, Richard A. ; Gerardo, Nicole M. ; Moran, Nancy ; Nakabachi, Atsushi ; Stern, David ; Tagu, Denis ; Wilson, Alex C.C. ; Muzny, Donna ; Kovar, Christie ; Cree, Andy ; Chacko, Joseph ; Chandrabose, Mimi N. ; Dao, Marvin Diep ; Dinh, Huyen H. ; Gabisi, Ramatu Ayiesha ; Hines, Sandra ; Hume, Jennifer ; Jhangian, Shalini N. ; Joshi, Vandita ; Lewis, Lora R. ; Liu, Yih Shin ; Lopez, John ; Morgan, Margaret B. ; Nguyen, Ngoc Bich ; Okwuonu, Geoffrey O. ; Ruiz, San Juana ; Santibanez, Jireh ; Wright, Rita A. ; Fowler, Gerald R. ; Hitchens, Matthew E. ; Lozado, Ryan J. ; Moen, Charles ; Steffen, David ; Warren, James T. ; Zhang, Jingkun ; Nazareth, Lynne V. ; Chavez, Dean ; Davis, Clay ; Lee, Sandra L. ; Patel, Bella Mayurkumar ; Pu, Ling Ling ; Bell, Stephanie N. ; Johnson, Angela Jolivet ; Vattathil, Selina ; Williams, Rex L. ; Shigenobu, Shuji ; Dang, Phat M. ; Morioka, Mizue ; Fukatsu, Takema ; Kudo, Toshiaki ; Miyagishima, Shin Ya ; Jiang, Huaiyang ; Worley, Kim C. ; Legeai, Fabrice ; Gauthier, Jean Pierre ; Collin, Olivier ; Zhang, Lan ; Chen, Hsiu Chuan ; Ermolaeva, Olga ; Hlavina, Wratko ; Kapustin, Yuri ; Kiryutin, Boris ; Kitts, Paul ; Maglott, Donna ; Murphy, Terence ; Pruitt, Kim ; Sapojnikov, Victor ; Souvorov, Alexandre ; Thibaud-Nissen, Françoise ; Câmara, Francisco ; Guigó, Roderic ; Stanke, Mario ; Solovyev, Victor ; Kosarev, Peter ; Gilbert, Don ; Gabaldón, Toni ; Huerta-Cepas, Jaime ; Marcet-Houben, Marina ; Pignatelli, Miguel ; Moya, Andrés ; Rispe, Claude ; Ollivier, Morgane ; Quesneville, Hadi ; Permal, Emmanuelle ; Llorens, Carlos ; Futami, Ricardo ; Hedges, Dale ; Robertson, Hugh M. ; Alioto, Tyler ; Mariotti, Marco ; Nikoh, Naruo ; McCutcheon, John P. ; Burke, Gaelen ; Kamins, Alexandra ; Latorre, Amparo ; Ashton, Peter ; Calevro, Federica ; Charles, Hubert ; Colella, Stefano ; Douglas, Angela E. ; Jander, Georg ; Jones, Derek H. ; Febvay, Gérard ; Kamphuis, Lars G. ; Kushlan, Philip F. ; Macdonald, Sandy ; Ramsey, John ; Schwartz, Julia ; Seah, Stuart ; Thomas, Gavin ; Vellozo, Augusto ; Cass, Bodil ; Degnan, Patrick ; Hurwitz, Bonnie ; Leonardo, Teresa ; Koga, Ryuichi ; Altincicek, Boran ; Anselme, Caroline ; Atamian, Hagop ; Barribeau, Seth M. ; Vos, Martin De; Duncan, Elizabeth ; Evans, Jay ; Ghanim, Murad ; Heddi, Abdelaziz ; Kaloshian, Isgouhi ; Vincent-Monegat, Carole ; Parker, Ben J. ; Pérez-Brocal, Vicente ; Rahbé, Yvan ; Spragg, Chelsea J. ; Tamames, Javier ; Tamarit, Daniel ; Tamborindeguy, Cecilia ; Vilcinskas, Andreas ; Bickel, Ryan D. ; Brisson, Jennifer A. ; Butts, Thomas ; Chang, Chun Che ; Christiaens, Olivier ; Davis, Gregory K. ; Duncan, Elizabeth ; Ferrier, David ; Iga, Masatoshi ; Janssen, Ralf ; Lu, Hsiao Ling ; McGregor, Alistair ; Miura, Toru ; Smagghe, Guy ; Smith, James ; Zee, Maurijn Van Der; Velarde, Rodrigo ; Wilson, Megan ; Dearden, Peter ; Edwards, Owain R. ; Gordon, Karl ; Hilgarth, Roland S. ; Rider, Stanley Dean ; Srinivasan, Dayalan ; Walsh, Thomas K. ; Ishikawa, Asano ; Jaubert-Possamai, Stéphanie ; Fenton, Brian ; Huang, Wenting ; Rizk, Guillaume ; Lavenier, Dominique ; Nicolas, Jacques ; Smadja, Carole ; Zhou, Jing Jiang ; Vieira, Filipe G. ; He, Xiao Li ; Liu, Renhu ; Rozas, Julio ; Field, Linda M. ; Campbell, Peter ; Carolan, James C. ; Fitzroy, Carol I.J. ; Reardon, Karen T. ; Reeck, Gerald R. ; Singh, Karam ; Wilkinson, Thomas L. ; Huybrechts, Jurgen ; Abdel-Latief, Mohatmed ; Robichon, Alain ; Veenstra, Jan A. ; Hauser, Frank ; Cazzamali, Giuseppe ; Schneider, Martina ; Williamson, Michael ; Stafflinger, Elisabeth ; Hansen, Karina K. ; Grimmelikhuijzen, Cornelis J.P. ; Price, Daniel R.G. ; Caillaud, Marina ; Fleet, Eric Van; Ren, Qinghu ; Gatehouse, John A. ; Brault, Véronique ; Monsion, Baptiste ; Diaz, Jason ; Hunnicutt, Laura ; Ju, Ho Jong ; Pechuan, Ximo ; Aguilar, José ; Cortés, Teresa ; Ortiz-Rivas, Benjamín ; Martínez-Torres, David ; Dombrovsky, Aviv ; Dale, Richard P. ; Davies, T.G.E. ; Williamson, Martin S. ; Jones, Andrew ; Sattelle, David ; Williamson, Sally ; Wolstenholme, Adrian ; Cottret, Ludovic ; Sagot, Marie France ; Heckel, David G. ; Hunter, Wayne - \ 2010
    PloS Biology 8 (2010)2. - ISSN 1544-9173

    Aphids are important agricultural pests and also biological models for studies of insect-plant interactions, symbiosis, virus vectoring, and the developmental causes of extreme phenotypic plasticity. Here we present the 464 Mb draft genome assembly of the pea aphid Acyrthosiphon pisum. This first published whole genome sequence of a basal hemimetabolous insect provides an outgroup to the multiple published genomes of holometabolous insects. Pea aphids are host-plant specialists, they can reproduce both sexually and asexually, and they have coevolved with an obligate bacterial symbiont. Here we highlight findings from whole genome analysis that may be related to these unusual biological features. These findings include discovery of extensive gene duplication in more than 2000 gene families as well as loss of evolutionarily conserved genes. Gene family expansions relative to other published genomes include genes involved in chromatin modification, miRNA synthesis, and sugar transport. Gene losses include genes central to the IMD immune pathway, selenoprotein utilization, purine salvage, and the entire urea cycle. The pea aphid genome reveals that only a limited number of genes have been acquired from bacteria; thus the reduced gene count of Buchnera does not reflect gene transfer to the host genome. The inventory of metabolic genes in the pea aphid genome suggests that there is extensive metabolite exchange between the aphid and Buchnera, including sharing of amino acid biosynthesis between the aphid and Buchnera. The pea aphid genome provides a foundation for post-genomic studies of fundamental biological questions and applied agricultural problems.

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