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.

Inhibition of gametogenesis by the cestode Ligula intestinalis in roach (Rutilus rutilus) is attenuated under laboratory conditions

Parasitology ◽  
2010 ◽  
Vol 138 (5) ◽  
pp. 648-659 ◽  
Author(s):  
ACHIM TRUBIROHA ◽  
HANA KROUPOVA ◽  
SABRINA N. FRANK ◽  
BERND SURES ◽  
WERNER KLOAS
Keyword(s):  
Steroid Receptors ◽  
Gonadosomatic Index ◽  
Plasma Concentrations ◽  
Secondary Growth ◽  
Parasite Burden ◽  
Rutilus Rutilus ◽  
Roach Rutilus Rutilus ◽  
Infected Female ◽  
Ligula Intestinalis ◽  
Laboratory Conditions

SUMMARYReproductive parameters of Ligula intestinalis-infected roach (Rutilus rutilus) which were held under long-tem laboratory conditions with unlimited food supply were investigated. Although uninfected and infected roach showed no difference in condition factor and both groups deposited perivisceral fat, the gonadosomatic-index was significantly lower in infected female and male roach. Quantitative histological analysis revealed that gonad development was retarded upon parasitization in both genders. In contrast to the phenotype described in the field, infected females were able to recruit follicles into secondary growth, but a high percentage of secondary growth follicles underwent atresia. In both genders, the histological data corresponded well with reduced expression of pituitary gonadotropins and lowered plasma concentrations of sex steroids, as revealed by real-time RT-PCR and ELISA, respectively. Furthermore, a reduction of vitellogenin mRNA and modulated expression of sex steroid receptors in the liver was demonstrated. Like in the field, there was a significant adverse impact of L. intestinalis on host reproductive physiology which could not be related to parasite burden. Our results show, for the first time, that maintenance under laboratory conditions can not abolish the deleterious effect of L. intestinalis on gametogenesis in roach, and indicate a specific inhibition of host reproduction by endocrine disruption.

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.

scholarly journals Abundance of helminth parasite in Channa striatus (Bloch, 1793) from Punarbhaba and Atrai rivers

2016 ◽  
Vol 25 (1) ◽  
pp. 39-46
Author(s):  
Sujon Kundu ◽  
Aminul I Bhuiyan
Keyword(s):  
Seasonal Changes ◽  
Significant Positive Correlation ◽  
Parasite Species ◽  
Helminth Parasites ◽  
Helminth Community ◽  
Dominant Group ◽  
Channa Striatus ◽  
Host Sex ◽  
Significant Difference ◽  
The Impact

The study was conducted to determine the impact of seasons, host size and sexes on the incidence of helminth community infecting Channa striatus (Bloch, 1793) from Punarbhaba and Atrai rivers of Dinajpur district. Four helminths were identified: one Cestoda, Bothriocephalus cuspidatus (Cooper, 1917); two Nematoda, Ascaridia spp. (Dujardin, 1845) and Camallanus intestinalus (Bashirullah, 1974); one Acanthocephala, Pallisentis ophiocephali (Thapar, 1930). Out of 75 hosts examined 52 were infected by 326 helminth parasites. Nematoda was the most dominant group (48.0%), followed by Acanthocephala (46.67%) and Cestoda (8.0%). The larger hosts were more infected than the smaller ones. A significant positive correlation was observed between the length of the host with respect to the abundance and prevalence of parasite for C. intentinalus and P. ophiocephali. Regarding the effect of seasonal changes, the prevalence of B. cuspidatus (14.81%) and Ascaridia spp. (22.22%) was highest in the rainy season. The highest prevalence of C. intestinalus (73.91%) was observed in winter. The prevalence of P. ophiocephali was high (84.0%) in summer. Except the abundance of B. cuspidatus (p = 0.147) all parasite species, Ascaridia spp. (p = 0.003), C. intestinalus (p < 0.01) and P. ophiocephali (p < 0.01) varied significantly among seasons. Overall prevalence of infection of male and female were 53.8% and 77.6%, respectively. A significant difference in the abundance of the parasite species with respect to host sex was observed only in C. intestinalus (Z = –2.886, p = 0.004).Dhaka Univ. J. Biol. Sci. 25(1): 39-46, 2016

scholarly journals Adaptation of Bivalve Molluscs to Environmental Conditions in the Coastal Region of El Jadida (Morocco): Case of Mytilus Galloprovincialis

2017 ◽  
Vol 13 (18) ◽  
pp. 226
Author(s):  
Essedaoui Aafaf ◽  
Messaoudi Abdelfettah ◽  
Ferssiwi Abdesslam ◽  
Massar Redouane ◽  
Bitar Abdelali
Keyword(s):  
Industrial Pollution ◽  
Mytilus Galloprovincialis ◽  
Coastal Region ◽  
Industrial Effluents ◽  
Condition Index ◽  
Temporal Variations ◽  
Reference Station ◽  
Significant Difference ◽  
El Jadida ◽  
The Impact

The aim of this study is to assess the impact of industrial pollution on the growth and reproduction of the mussel Mytilus galloprovincialis from coastal region of El Jadida (Morocco). To this aim, three stations (S1, S2 and S3) are chosen according to their proximity to the industrial effluents of the chemical complex. The seawater and mussels (N = 100/ station) samples have been randomly and monthly collected for a period of 6 months (February-July 16). Mussels are distributed in 6 classes of size and measures of condition index and gonadic index are performed in the most common size classes. The results of the analysis of physicochemical parameters of the water show spatio-temporal variations with an acidic pH, high temperature and low salinity in the station near of industrials effluents. Regarding condition index and the gonadic index, there is no significant difference between the mussels collected from the reference station (S2) and the polluted station (S3). This can be explained partly by the adoption of a strategy of adaptation to the environmental stress caused by the industrial pollution.

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 Reproductive cycle of Bolinus brandaris (Gastropoda: Muricidae) in the Gulf of Gabès (southern Tunisia)

2013 ◽  
Vol 14 (1) ◽  
pp. 24 ◽  
Author(s):  
K. ELHASNI ◽  
P. VASCONCELOS ◽  
M. GHORBEL ◽  
O. JARBOUI
Keyword(s):  
Reproductive Cycle ◽  
Sexual Maturity ◽  
Fishery Management ◽  
Gonadosomatic Index ◽  
Condition Index ◽  
Spawning Season ◽  
Gonad Maturation ◽  
Gulf Of Gabes ◽  
Gulf Of Gabès ◽  
Bolinus Brandaris

The reproductive cycle of the purple dye murex (Bolinus brandaris) from the Gulf of Gabès was studied through gonad histology and calculation of bio-physiological indices (general condition index - K and gonadosomatic index - GSI). The shell length at first sexual maturity (SL50) of B. brandaris was also investigated using a macroscopic maturation scale. The population sex ratio was statistically unbalanced (M:F = 1:1.5), with a significant dominance of females. Monthly variation in gonad maturation stages, K and GSI revealed that B. brandaris has an annual reproductive cycle, long period of gonadal activity and slight asynchrony between sexes. The spawning season extended between April and July, with a clear spawning peak from May to June. The SL50 was reached at 56.4 mm in females and 54.6 mm in males. At present, B. brandaris has no commercial value in Tunisia, but it is predictable that it will become a fishery-exploited species in the near future. The present data, particularly the timing of spawning season and the size at first sexual maturity, constitute baseline information for the proposal of fishery management measures, aiming to ensure sustainable exploitation and long-term preservation of this alternative fishing resource.

scholarly journals Relationship of Condition Index and Reproductive Status of Black Snail, Fannus ater in Merchang Lagoon

2020 ◽  
Vol 2 (1) ◽  
pp. 1-8
Author(s):  
Nurul Husna Hassan ◽  
Roslizawati Ab Lah
Keyword(s):  
Biological Activities ◽  
Gonadosomatic Index ◽  
Dry Weight ◽  
Condition Index ◽  
Abundant Species ◽  
Reproductive Status ◽  
Future Research ◽  
Weight Measurement ◽  
Significant Difference ◽  
Condition Indices

Black snail, Faunus ater is an abundant species in Malaysia yet not many research have focused on its physiological and biological activities. This research aimed to assess the condition index (CI) and reproductive status based on the gonadosomatic index (GSI) for short-term duration. Samples were collected monthly from Merchang Lagoon, from November 2018 to January 2019. Four different types of condition indices equation were applied in this study and the results revealed that there were significant differences between four equations for measuring the CI (P=0.000). However, the result for the GSI shows no significant difference between three month of sampling (P>0.05). CI based on fresh weight measurement (Fww/Tww x 100) and dry weight measurement (Fdw/Fww x 100) reached its peak when GSI decreased. The rest of the trend for CI fluctuated and CI was not affected by GSI. Overall, this study concluded that, there were trends observed in CI and GSI for the black snails. However, it is suggested that longer term observation in future research is needed have a better understanding on the black snails.

Measuring Impact of Stress in Sandwich Generation Caring for Demented Parents

GeroPsych ◽  
2014 ◽  
Vol 27 (4) ◽  
pp. 171-179 ◽  
Author(s):  
Laurence M. Solberg ◽  
Lauren B. Solberg ◽  
Emily N. Peterson
Keyword(s):  
Factor Analysis ◽  
Exploratory Factor Analysis ◽  
Social Worker ◽  
Resource Availability ◽  
Well Being ◽  
Sandwich Generation ◽  
Item Questionnaire ◽  
Significant Difference ◽  
Adult Caregivers ◽  
The Impact

Stress in caregivers may affect the healthcare recipients receive. We examined the impact of stress experienced by 45 adult caregivers of their elderly demented parents. The participants completed a 32-item questionnaire about the impact of experienced stress. The questionnaire also asked about interventions that might help to reduce the impact of stress. After exploratory factor analysis, we reduced the 32-item questionnaire to 13 items. Results indicated that caregivers experienced stress, anxiety, and sadness. Also, emotional, but not financial or professional, well-being was significantly impacted. There was no significant difference between the impact of caregiver stress on members from the sandwich generation and those from the nonsandwich generation. Meeting with a social worker for resource availability was identified most frequently as a potentially helpful intervention for coping with the impact of stress.

Implicit and explicit corrective feedback and feedback exposure conditions

2020 ◽  
Vol 4 (1) ◽  
pp. 3-48
Author(s):  
Takehiro Iizuka ◽  
Kimi Nakatsukasa
Keyword(s):  
Explicit Knowledge ◽  
Corrective Feedback ◽  
Significant Difference ◽  
Oral Corrective Feedback ◽  
Post Test ◽  
Picture Description ◽  
Potential Factors ◽  
Implicit And Explicit ◽  
Instructional Settings ◽  
The Impact

This exploratory study examined the impact of implicit and explicit oral corrective feedback (CF) on the development of implicit and explicit knowledge of Japanese locative particles (activity de, movement ni and location ni) for those who directly received CF and those who observed CF in the classroom. Thirty-six college students in a beginning Japanese language course received either recast (implicit), metalinguistic (explicit) or no feedback during an information-gap picture description activity, and completed a timed picture description test (implicit knowledge) and an untimed grammaticality judgement test (explicit knowledge) in a pre-test, immediate post-test and delayed post-test. The results showed that overall there was no significant difference between CF types, and that CF benefited direct and indirect recipients similarly. Potential factors that might influence the effectiveness of CF, such as instructional settings, complexity of target structures and pedagogy styles, are discussed.

Reducing the Social Stigma Associated with Obsessive Compulsive Disorder: A Controlled Trial of an Intervention Program in a Turkish Community Sample

2020 ◽  
Vol 20 (2) ◽  
pp. 101-120
Author(s):  
Ayça Aktaç Gürbüz ◽  
Orçun YORULMAZ ◽  
Gülşah DURNA
Keyword(s):  
Obsessive Compulsive Disorder ◽  
Intervention Program ◽  
Controlled Trial ◽  
Community Sample ◽  
Case Vignette ◽  
Control Group ◽  
Obsessive Compulsive ◽  
Compulsive Disorder ◽  
Significant Difference ◽  
The Impact

Scientific research into the reduction of stigmatization, particularly related to specific problems such as Obsessive-Compulsive Disorder (OCD), is scarce. In the present study, we examine the impact of a video-based antistigma intervention program for OCD in a pretest-posttest control group research. After being randomly assigned to either an intervention (n= 101) or control group (n= 96), the participants reported their attitudes on a hypothetical case vignette before and after OCD vs. Multiple Sclerosis (MS) videos, and again six months later as a follow up assessment. The mixed design analyses for the group comparisons indicated that although there was no significant difference in the measures of the control group, the participants watching the anti-stigma OCD video, in which the focus was psychoeducation and interaction strategies, reported significantly lower scores on social distances and negative beliefs for the case vignettes they read, and this difference was maintained six months later. Then, the present results indicate the effectiveness of our anti-stigma intervention program for OCD. Interventions to reduce stigmatization can also be viewed as effective tools for changing the attitudes of people toward OCD, although further research and applications are needed related to specific disorders if a longlasting impact is to be achieved.

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