Host manipulation by Ligula intestinalis: accident or adaptation?

Parasitology ◽  
2001 ◽  
Vol 123 (5) ◽  
pp. 519-529 ◽  
Author(s):  
S. P. BROWN ◽  
G. LOOT ◽  
B. T. GRENFELL ◽  
J. F. GUÉGAN
Keyword(s):  
Linear Models ◽  
Rutilus Rutilus ◽  
Infected Fish ◽  
Life Cycles ◽  
Fish Host ◽  
Host Manipulation ◽  
Ligula Intestinalis ◽  
Game Theoretic ◽  
Effect Hypothesis ◽  
The Impact

Numerous studies have demonstrated that parasites with complex life-cycles can cause phenotypic modifications in their hosts that lead to an increased rate of transmission, and suggest that these modifications are the result of parasitic adaptations to manipulate the host. Little attention is paid, however, to separating the possibility of adaptive host manipulation from incidental (if fortuitous) side-effects of infection. In this study we combine statistical and analytical tools to interpret the impact of the macroparasite Ligula intestinalis L. (Cestoda, Pseudophyllidea) on the behaviour of its intermediate fish host (the roach, Rutilus rutilus L.), using field data on a natural system. Two distinct sets of generalized linear models agree that both the presence and the intensity of infection contribute to a modified behavioural response in the host. This was illustrated by a preference for the lake-edge in infected fish during autumn. Furthermore, the effect of parasites upon their host is heterogeneous with respect to parasite size, with larger parasite individuals having a disproportionate impact. A series of game-theoretic models of adaptive host manipulation illustrate a potential rationale for a size-dependent manipulation strategy in parasites. These findings illustrate the potential complexity and functionality of the impact of L. intestinalis upon its fish host, which together reduce the parsimony of the alternative ‘incidental effect’ hypothesis.

Influence of Ligula intestinalis plerocercoids (Cestoda: Diphyllobothriidea) on the occurrence of eyeflukes in roach (Rutilus rutilus) from a lake in south-east England

2018 ◽  
Vol 93 (1) ◽  
pp. 66-70 ◽  
Author(s):  
N.J. Morley ◽  
J.W. Lewis
Keyword(s):  
Rutilus Rutilus ◽  
Body Cavity ◽  
Infected Fish ◽  
Fish Host ◽  
Helminth Species ◽  
Roach Rutilus Rutilus ◽  
Ligula Intestinalis ◽  
Freshwater Habitats ◽  
Concurrent Infections ◽  
South East England

AbstractVertebrate hosts commonly harbour concurrent infections of different helminth species which may interact with each other in a synergistic, antagonistic or negligible manner. Direct interactions between helminths that share a common site in the host have been regularly reported, but indirect interactions between species that occur in different sites are rarely described, especially in fish hosts. Plerocercoids of Ligula intestinalis are common infections of the peritoneal (body) cavity of roach (Rutilus rutilus) in freshwater habitats. These larval cestodes can cause extensive systemic pathologies to the fish host, which in turn may alter its susceptibility as a target host for other helminth species. The present study, using an existing dataset, investigates the influence of L. intestinalis (ligulosis) on frequently occurring eyefluke infections in roach sampled from a lake in south-east England. The occurrence of two species of eyefluke (Diplostomum sp. and Tylodelphys sp.) in the roach population demonstrated no significant levels of interaction with each other. The prevalence but not mean intensity or abundance of Diplostomum sp. was significantly increased in ligulosed roach, while the incidence of Tylodelphys sp. remained unchanged. Analyses of bilateral asymmetry in the occurrence of eyeflukes in left and right eyes of infected fish demonstrate that Tylodelphys sp. shows significant asymmetry in non-ligulosed roach, which is not replicated in ligulosed individuals. In contrast, Diplostomum sp. shows no evidence of asymmetry in either ligulosed or non-ligulosed fish.

scholarly journals The tapeworm Ligula intestinalis (Cestoda: Pseudophyllidea) inhibits LH expression and puberty in its teleost host, Rutilus rutilus

Reproduction ◽  
2005 ◽  
Vol 130 (6) ◽  
pp. 939-945 ◽  
Author(s):  
V Carter ◽  
R Pierce ◽  
S Dufour ◽  
C Arme ◽  
D Hoole
Keyword(s):  
Pituitary Gland ◽  
Rutilus Rutilus ◽  
Gonadal Development ◽  
Body Cavity ◽  
Infected Fish ◽  
Fish Host ◽  
The Body ◽  
Mrna Levels ◽  
Ligula Intestinalis ◽  
The Brain

The tapewormLigula intestinalisoccurs in the body cavity of its cyprinid second intermediate host, in this study the roachRutilus rutilus, and inhibits host gonadal development. The mechanism by which infected fish are prevented from reproducing is unknown. Comparison of parameters, such as body length and weight, and condition factor and age, between infected and uninfected individuals, indicated only minor effects of parasitism on growth and condition. In contrast, seasonal gonadal development, as observed in uninfected fish, did not occur in infected fish, and gonads remained small and blocked at the primary oocyte stage in female roach. As immature ovaries and testes are still present, the parasite is presumed to act upon the brain–pituitary–gonadal axis of the fish to inhibit further development of reproductive organs. We investigated theLigula/fish interaction at the level of the pituitary gland by determination of gonadotrophin (LH) content using a heterologous RIA for carp (Cyprinus carpio) LHβ subunit. The results indicated that the pituitary glands of infected roach contained approximately 50% less LH than non-infected fish. After the cloning and sequencing of roach LHβ subunit, we measured roach LHβ mRNA levels by real-time RT-PCR. A corresponding 50% reduction in LHβ mRNA pituitary levels was determined. These results reflect a significant and measurable effect of parasitism on the pituitary gland, and lend support to the hypothesis that excretory/secretory products released from the parasite interact with the brain–pituitary–gonadal axis of the fish host and thus inhibit gonadal development.

Host switch and infestation by Ligula intestinalis L. in a silver bream (Blicca bjoerkna L.) population

Parasitology ◽  
2012 ◽  
Vol 139 (3) ◽  
pp. 406-417 ◽  
Author(s):  
M. VANACKER ◽  
G. MASSON ◽  
J-N. BEISEL
Keyword(s):  
Gonadosomatic Index ◽  
Rutilus Rutilus ◽  
Condition Index ◽  
Gonad Maturation ◽  
Host Switch ◽  
Ligula Intestinalis ◽  
Fat Reserves ◽  
Host Sex ◽  
Significant Difference ◽  
The Impact

SUMMARYSampling of the fish community was carried out for 20 years in the Mirgenbach reservoir, in North-Eastern France. The prevalence and the mean intensity of Ligula intestinalis (Cestoda) were analysed in roach (Rutilus rutilus) and silver bream (Blicca bjoerkna) populations, the main two infected species. The aim of this study was to investigate the host switch from roach to silver bream and the consequences of L. intestinalis infestation in silver bream, which is an unusual host for this parasite as Ligula parasitism in silver bream appears to be rare. We analysed in detail the relationships between parasitism index (PI), gonadosomatic index (GSI), perivisceral fat abundance (PFA) and condition index (CI) in the silver bream population. In 1998, prevalence of L. intestinalis highlighted a clear host switch from roach to silver bream. In the silver bream population, young fish were the most severely infected and the impact of plerocercoids appeared to be different depending on the host sex. In male silver bream, plerocercoids drew energy from fat reserves even if GSI was also slightly impacted. On the contrary, in females energy was diverted from gonad maturation rather than from perivisceral fat reserves. No significant difference was observed in terms of CI in either sex.

Experimental demonstration of a behavioural modification in a cyprinid fish, Rutilus rutilus (L.), induced by a parasite, Ligula intestinalis (L.)

2002 ◽  
Vol 80 (4) ◽  
pp. 738-744 ◽  
Author(s):  
Géraldine Loot ◽  
Stéphane Aulagnier ◽  
Sovan Lek ◽  
Frédéric Thomas ◽  
Jean-François Guégan
Keyword(s):  
Rutilus Rutilus ◽  
Infected Fish ◽  
Experimental Demonstration ◽  
Roach Rutilus Rutilus ◽  
Ligula Intestinalis ◽  
Behavioural Changes ◽  
Proximate Mechanisms ◽  
Behavioural Modification ◽  
Avian Predators ◽  
The Vertical Distribution

Behavioural changes in parasitized hosts have been experimentally investigated by comparing the swimming behaviour of roach, Rutilus rutilus, infected by the tapeworm Ligula intestinalis with that of uninfected roach when they were exposed to the same overhead heron stimulus. Before the stimulus was presented, infected fish swam close to the surface and uninfected fish were preferentially found near the bottom of the tank. The stimulus clearly induced a change in the vertical distribution of infected fish only. On the other hand, infected roach were less active than un infected fish before, during, and after the stimulus was presented. Proximate mechanisms of these behavioural changes are discussed. These behavioural differences, i.e., roach surfacing, swimming, and response to stimulus, probably favour the predation of infected roach by avian predators.

Endocrine effects of the tapeworm Ligula intestinalis in its teleost host, the roach (Rutilus rutilus)

Parasitology ◽  
2009 ◽  
Vol 137 (4) ◽  
pp. 697-704 ◽  
Author(s):  
P. GERAUDIE ◽  
C. BOULANGE-LECOMTE ◽  
M. GERBRON ◽  
N. HINFRAY ◽  
F. BRION ◽  
...  
Keyword(s):  
Plasma Concentrations ◽  
Endocrine System ◽  
Reproductive Function ◽  
Rutilus Rutilus ◽  
Infected Fish ◽  
Gonad Maturation ◽  
Aromatase Activity ◽  
Roach Rutilus Rutilus ◽  
Ligula Intestinalis ◽  
Brain Aromatase

SUMMARYThe effects of parasite infection by the cestode Ligula intestinalis on the reproductive function and endocrine system of wild roach Rutilus rutilus were evaluated. Gonad maturation, plasma vitellogenin, plasma steroid concentrations (i.e. progesterone, 11-keto-testosterone and 17-β-estradiol) and brain aromatase activity were investigated in relation with parasitization. A low prevalence (8%) of ligulosed roach and a moderate impact of parasitization (mean parasitization index of 8·8%) were found in the studied population. Inhibition of gonad maturation generally resulted from infestation but 5% of the ligulosed roach nevertheless reached maturity. Main sex steroid plasma content was depleted in both genders. Male 11-keto-testosterone, female 17-β-estradiol and progesterone plasma concentrations of both genders were, respectively, 27, 5 and 3 times lower in ligulosed fish when compared to their non-infected counterparts. Progesterone levels were negatively correlated with the parasitization index in females. Brain aromatase activity of infected roach was reduced to 50% of that of the non-infected fish. These results demonstrate significant negative effects on the reproductive function of wild roach infected by the tapeworm L. intestinalis collected from a site with low contamination.

scholarly journals Effect of temperature, CO2 and O2 on motility and mobility of Anisakidae larvae

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Aiyan Guan ◽  
Inge Van Damme ◽  
Frank Devlieghere ◽  
Sarah Gabriël
Keyword(s):  
Enzymatic Digestion ◽  
Infected Fish ◽  
Effect Of Temperature ◽  
Video Recordings ◽  
Different Temperatures ◽  
Semi Solid ◽  
Zoonotic Parasites ◽  
The Impact ◽  
Phosphate Buffered Saline

AbstractAnisakidae, marine nematodes, are underrecognized fish-borne zoonotic parasites. Studies on factors that could trigger parasites to actively migrate out of the fish are very limited. The objective of this study was to assess the impact of different environmental conditions (temperature, CO2 and O2) on larval motility (in situ movement) and mobility (migration) in vitro. Larvae were collected by candling or enzymatic digestion from infected fish, identified morphologically and confirmed molecularly. Individual larvae were transferred to a semi-solid Phosphate Buffered Saline agar, and subjected to different temperatures (6 ℃, 12 ℃, 22 ℃, 37 ℃) at air conditions. Moreover, different combinations of CO2 and O2 with N2 as filler were tested, at both 6 °C and 12 °C. Video recordings of larvae were translated into scores for larval motility and mobility. Results showed that temperature had significant influence on larval movements, with the highest motility and mobility observed at 22 ℃ for Anisakis spp. larvae and 37 ℃ for Pseudoterranova spp. larvae. During the first 10 min, the median migration of Anisakis spp. larvae was 10 cm at 22 ℃, and the median migration of Pseudoterranova spp. larvae was 3 cm at 37 ℃. Larval mobility was not significantly different under the different CO2 or O2 conditions at 6 °C and 12 ℃. It was concluded that temperature significantly facilitated larval movement with the optimum temperature being different for Anisakis spp. and Pseudoterranova spp., while CO2 and O2 did not on the short term. This should be further validated in parasite-infected/spiked fish fillets.

scholarly journals Advances of 2nd Life Applications for Lithium Ion Batteries from Electric Vehicles Based on Energy Demand

2021 ◽  
Vol 13 (10) ◽  
pp. 5726
Author(s):  
Aleksandra Wewer ◽  
Pinar Bilge ◽  
Franz Dietrich
Keyword(s):  
Life Cycle ◽  
Lithium Ion Batteries ◽  
Electric Vehicles ◽  
Energy Demand ◽  
Lithium Ion ◽  
Life Cycles ◽  
Future Research ◽  
Research Areas ◽  
Study Results ◽  
The Impact

Electromobility is a new approach to the reduction of CO2 emissions and the deceleration of global warming. Its environmental impacts are often compared to traditional mobility solutions based on gasoline or diesel engines. The comparison pertains mostly to the single life cycle of a battery. The impact of multiple life cycles remains an important, and yet unanswered, question. The aim of this paper is to demonstrate advances of 2nd life applications for lithium ion batteries from electric vehicles based on their energy demand. Therefore, it highlights the limitations of a conventional life cycle analysis (LCA) and presents a supplementary method of analysis by providing the design and results of a meta study on the environmental impact of lithium ion batteries. The study focuses on energy demand, and investigates its total impact for different cases considering 2nd life applications such as (C1) material recycling, (C2) repurposing and (C3) reuse. Required reprocessing methods such as remanufacturing of batteries lie at the basis of these 2nd life applications. Batteries are used in their 2nd lives for stationary energy storage (C2, repurpose) and electric vehicles (C3, reuse). The study results confirm that both of these 2nd life applications require less energy than the recycling of batteries at the end of their first life and the production of new batteries. The paper concludes by identifying future research areas in order to generate precise forecasts for 2nd life applications and their industrial dissemination.

scholarly journals Effect of Barley Sowing Density on the Integrated Weed Management of Lolium rigidum (Annual Ryegrass) in Mediterranean Dryland: A Modeling Approach

Agronomy ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1565
Author(s):  
María Belén D’Amico ◽  
Guillermo R. Chantre ◽  
Guillermo L. Calandrini ◽  
José L. González-Andújar
Keyword(s):  
Weed Management ◽  
Life Cycles ◽  
Integrated Weed Management ◽  
Future Research ◽  
Seed Removal ◽  
Weed Infestation ◽  
High Control ◽  
Weed Dynamics ◽  
The Impact

Population models are particularly helpful for understanding long-term changes in the weed dynamics associated with integrated weed management (IWM) strategies. IWM practices for controlling L. rigidum are of high importance, mainly due to its widespread resistance that precludes chemical control as a single management method. The objective of this contribution is to simulate different IWM scenarios with special emphasis on the impact of different levels of barley sowing densities on L. rigidum control. To this effect, a weed–crop population model for both L. rigidum and barley life cycles was developed. Our results point out: (i) the necessity of achieving high control efficiencies (>99%), (ii) that the increase of twice the standard sowing density of barley resulted in a reduction of 23.7% of the weed density, (iii) non-herbicide-based individual methods, such as delayed sowing and weed seed removal at harvest, proved to be inefficient for reducing drastically weed population, (iv) the implementation of at least three control tactics (seed removal, delay sowing and herbicides) is required for weed infestation eradication independently of the sowing rate, and (v) the effect of an increase in the sowing density is diluted as a more demanding weed control is reached. Future research should aim to disentangle the effect of different weed resistance levels on L. rigidum population dynamics and the required efficiencies for more sustainable IWM programs.

scholarly journals Socio-economic consequences of mental distress: quantifying the impact of self-reported mental distress on the days of incapacity to work and medical costs in a two-year period: a longitudinal study in Germany

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Gerhard Müller ◽  
Manuela Bombana ◽  
Monika Heinzel-Gutenbrenner ◽  
Nikolaus Kleindienst ◽  
Martin Bohus ◽  
...  
Keyword(s):  
Mental Disorders ◽  
Mental Distress ◽  
Linear Models ◽  
Longitudinal Research ◽  
Depression Scale ◽  
Routine Data ◽  
Medical Costs ◽  
First Year ◽  
Second Year ◽  
The Impact

Abstract Background Mental disorders are related to high individual suffering and significant socio-economic burdens. However, it remains unclear to what extent self-reported mental distress is related to individuals’ days of incapacity to work and their medical costs. This study aims to investigate the impact of self-reported mental distress for specific and non-specific days of incapacity to work and specific and non-specific medical costs over a two-year span. Method Within a longitudinal research design, 2287 study participants’ mental distress was assessed using the Hospital Anxiety and Depression Scale (HADS). HADS scores were included as predictors in generalized linear models with a Tweedie distribution with log link function to predict participants’ days of incapacity to work and medical costs retrieved from their health insurance routine data during the following two-year period. Results Current mental distress was found to be significantly related to the number of specific days absent from work and medical costs. Compared to participants classified as no cases by the HADS (2.6 days), severe case participants showed 27.3-times as many specific days of incapacity to work in the first year (72 days) and 10.3-times as many days in the second year (44 days), and resulted in 11.4-times more medical costs in the first year (2272 EUR) and 6.2-times more in the second year (1319 EUR). The relationship of mental distress to non-specific days of incapacity to work and non-specific medical costs was also significant, but mainly driven from specific absent days and specific medical costs. Our results also indicate that the prevalence of presenteeism is considerably high: 42% of individuals continued to go to work despite severe mental distress. Conclusions Our results show that self-reported mental distress, assessed by the HADS, is highly related to the days of incapacity to work and medical costs in the two-year period. Reducing mental distress by improving preventive structures for at-risk populations and increasing access to evidence-based treatments for individuals with mental disorders might, therefore, pay for itself and could help to reduce public costs.

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