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排序方式: 共有380条查询结果,搜索用时 15 毫秒
1.
Invasive Chinese pond mussel Sinanodonta woodiana threatens native mussel reproduction by inducing cross‐resistance of host fish 下载免费PDF全文
Seth W. Donrovich Karel Douda Věra Plechingerová Kateřina Rylková Pavel Horký Ondřej Slavík Huan‐Zhang Liu Martin Reichard Manuel Lopes‐Lima Ronaldo Sousa 《水产资源保护:海洋与淡水生态系统》2017,27(6):1325-1333
- The effects of invasive alien species (IAS) on host–affiliate relationships are often subtle and remain unnoticed or insufficiently quantified. The global decline of freshwater unionid mussel species has been attributed to many causes, but little is known about the interactions of IAS, with their complex life cycle, which includes an obligatory parasitic stage (the glochidium) that develops on fishes.
- The capacity of a European freshwater mussel, Anodonta anatina, to develop on its widespread fish host, Squalius cephalus was tested experimentally, after previous infestations by the IAS, Sinanodonta (Anodonta) woodiana. The initial attachment of glochidia, the length of the parasitic period, and the metamorphosis success rate of A. anatina glochidia were compared among treatments of different priming infestation intensities.
- The metamorphosis success rate of the native A. anatina glochidia was strongly reduced (Wilcoxon Signed‐Rank Test, P < 0.001) and declined by 42.1 and 45.4% on fish hosts that were previously exposed to S. woodiana by single and multiple priming infestations, respectively, in comparison with the control group. Such cross‐resistance is expected to decrease significantly the quality of the host resources available to native mussels.
- This study provides the first evidence of the host‐mediated adverse impact of invasive S. woodiana on native mussel species. These results also highlight the importance of potential competition for hosts between threatened groups of affiliate species and their invasive counterparts, which should be reflected in conservation strategies.
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Local adaptation studies and conservation: Parasite–host interactions between the endangered freshwater mussel Unio crassus and its host fish 下载免费PDF全文
Lea D. Schneider P. Anders Nilsson Johan Höjesjö E. Martin Österling 《水产资源保护:海洋与淡水生态系统》2017,27(6):1261-1269
- Parasite–host interactions can involve strong reciprocal selection pressure, and may lead to locally adapted specializations. The highly threatened unionoid mussels are temporary parasites on fish, but local adaptation has not yet been investigated for many species.
- Patterns of local adaptation of one of Europe's most threatened unionoids, the thick‐shelled river mussel (Unio crassus) were investigated. Eurasian minnows (Phoxinus phoxinus) from two rivers (separate drainage areas) were cross‐infested in the laboratory with sympatric and allopatric mussel larvae, while bullheads (Cottus gobio), inhabiting only one of the rivers, were infested with sympatric or allopatric mussel larvae. Larval encystment, juvenile mussel excystment and survival were measured.
- For one river, but not the other, juvenile excystment from P. phoxinus was highest when infested with sympatric mussels. The opposite pattern was found for C. gobio in this river, where juvenile excystment and post‐parasitic juvenile survival from allopatric C. gobio were highest. The results thus cannot confirm local adaptation of U. crassus to P. phoxinus in the study rivers, as excystment was not consistently higher in all sympatric mussel–host combinations, whereas there were potential maladaptive signs of U. crassus in relation to C. gobio. There was no loss of encysted larvae 3 days after infestation until juvenile excystment. Most juveniles were excysted between 17 and 29 days after infestation, and the numbers of excysted juveniles increased with fish size.
- The results have implications for parasite–host ecology and conservation management with regard to unionoid propagation and re‐introduction. This includes the need to (1) test suitability and adaptation patterns between U. crassus and multiple host fish species, (2) evaluate the suitability of certain unionoids and host fish strains after more than 3 days, and (3) determine whether large fish produce more juvenile mussels than smaller fish.
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风险(risk)是由一种或多种危害因子而引发危害事件的一种可能性或概率。危害因子可能属于物理的、化学的、微生物的范畴,病原微生物中的细菌、病毒、寄生虫等都可成为引发危害事件的风险因子。评估某一因子是否对人或其他生物构成威胁以及所危害的程度显得至关重要。事实上,存在于环境中的危险因子及其多种可能的传播途径都会引发多种危害性事件。因此,要想充分了解并揭示由危害因子引发危害的概率,以及其随后对人类健康造成的危害并非易事。风险评估则是对不良结果或不期望事件发生几率进行描述及定量的系统过程,现已被视为一种用于揭示存在于环境中的各种危害及其对人类健康造成的影响的方法。论文主要对食源性寄生虫风险评估的方法进行全面阐述。 相似文献
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Serge MORAND Frédéric BORDES Hsuan‐Wien CHEN Julien CLAUDE Jean‐François COSSON Maxime GALAN Gábor Á CZIRJÁK Alex D GREENWOOD Alice LATINNE Johan MICHAUX Alexis RIBAS 《Integrative zoology》2015,10(5):409-423
We summarize the current knowledge on parasitism‐related invasion processes of the globally invasive Rattus lineages, originating from Asia, and how these invasions have impacted the local epidemiology of rodent‐borne diseases. Parasites play an important role in the invasion processes and successes of their hosts through multiple biological mechanisms such as “parasite release,” “immunocompetence advantage,” “biotic resistance” and “novel weapon.” Parasites may also greatly increase the impact of invasions by spillover of parasites and other pathogens, introduced with invasive hosts, into new hosts, potentially leading to novel emerging diseases. Another potential impact is the ability of the invader to amplify local parasites by spillback. In both cases, local fauna and humans may be exposed to new health risks, which may decrease biodiversity and potentially cause increases in human morbidity and mortality. Here we review the current knowledge on these processes and propose some research priorities. 相似文献
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Kara A. Brown Amy L. Johnson Susan J. Bender Thomas J. Nolan Bianca Pfisterer JoAnn Slack Elinor Willis Emily K. Rule 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》2023,37(2):735-739
A 5-year-old imported Zangersheide gelding was evaluated for SC swellings over both forelimbs and lameness localized to the distal metacarpus. Ultrasound examination of the SC masses was compatible with verminous granulomas. Linear hyperechoic foci were present within the suspensory ligament branches of both forelimbs, suggestive of ligamentous parasitic infiltrates. A diagnosis of onchocerciasis was confirmed on biopsy of a SC mass. The gelding was treated with ivermectin and a tapering course of PO dexamethasone but was eventually euthanized. Necropsy confirmed the presence of SC eosinophilic granulomas and degenerative suspensory ligament desmitis, both with intralesional nematodes. Given the location and appearance of the nematode, a diagnosis of Onchocerca sp., most likely O. reticulata, was made. Onchocerciasis should be included as a differential diagnosis for multifocal suspensory ligament desmitis with these sonographic characteristics when paired with SC masses in imported European Warmbloods. 相似文献
8.
《Veterinary parasitology》2015,207(1-2):49-55
Natural anti-parasitic compounds in plants such as condensed tannins (CT) have anthelmintic properties against a range of gastrointestinal nematodes, but for other helminths such effects are unexplored. The aim of this study was to assess the effects of CT from three different plant extracts in a model system employing the rat tapeworm, Hymenolepis diminuta, in its intermediate host, Tenebrio molitor. An in vitro study examined infectivity of H. diminuta cysticercoids (excystation success) isolated from infected beetles exposed to different concentrations of CT extracts from pine bark (PB) (Pinus sps), hazelnut pericarp (HN) (Corylus avellana) or white clover flowers (WC) (Trifolium repens), in comparison with the anthelmintic drug praziquantel (positive control). In the in vitro study, praziquantel and CT from all three plant extracts had dose-dependent inhibitory effects on cysticercoid excystation. The HN extract was most effective at inhibiting excystation, followed by PB and WC. An in vivo study was carried out on infected beetles (measured as cysticercoid establishment) fed different doses of PB, HN and praziquantel. There was a highly significant inhibitory effect of HN on cysticercoid development (p = 0.0002). Overall, CT showed a promising anti-cestodal effect against the metacestode stage of H. diminuta. 相似文献
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Isabel Guadano Procesi Azzurra Carnio Federica Berrilli Margherita Montalbano Di Filippo Alessia Scarito Cristina Amoruso Marco Barni Marco Ruffini Giulia Barlozzari Manuela Scarpulla Claudio De Liberato 《Zoonoses and public health》2022,69(1):46-54
Giardia duodenalis is the most common intestinal protozoan in humans and animals worldwide, including eight morphologically identical assemblages, infecting pets, livestock, wildlife and human beings. Assemblages A and B are those with the higher zoonotic potential, and they have been detected in several mammals other than humans; the others (C to H) show a higher host specificity. Cats can harbour both the specific Assemblage F and the zoonotic ones A and B. Several studies have been carried out on G. duodenalis genotypes in cats; however, the role of this species in the epidemiology of giardiasis is still poorly understood. In this scenario, the present study carried out the detection and genetic characterization at sub-assemblage level of G. duodenalis from colony stray cats in central Italy. In the period 2018–2019, 133 cat faecal samples were analysed for the presence of G. duodenalis cysts by a direct immunofluorescence assay. Positive samples were subsequently subjected to molecular analyses for assemblage/sub-assemblage identification. Forty-seven samples (35.3%) were positive for G. duodenalis cysts by immunofluorescence. G. duodenalis DNA was amplified at SSU-rDNA locus from 39 isolates: 37 were positive for zoonotic Assemblage A and 2 showed a mixed infection (A + B). Positive results for the β-giardin gene were achieved for 25 isolates. Sequence analysis revealed 16 isolates belonging to Sub-assemblage AII and 8 to Sub-assemblage AIII. One isolate resulted as ambiguous AI/AIII. Large sequence variability at the sub-assemblage level was detected, with several double peaks and mutations, making complex a proper isolate allocation. When compared with previous studies, the 35.3% prevalence of G. duodenalis in cats reported in the present article was surprisingly high. Moreover, all positive cats resulted to be infected with zoonotic assemblages/sub-assemblages, thus indicating stray cats as a possible source of human giardiasis and highlighting the sanitary relevance of cat colonies in the study area. 相似文献