scholarly journals An efficient photograph-based quantitative method for assessing castrating trematode parasites in bivalve molluscs

Parasitology ◽  
2020 ◽  
Vol 147 (12) ◽  
pp. 1375-1380 ◽  
Author(s):  
Joshua I. Brian ◽  
David C. Aldridge
Keyword(s):  
Reproductive Capacity ◽  
Bivalve Molluscs ◽  
Intensity Of Infection ◽  
Important Species ◽  
Gonad Tissue ◽  
Digenean Trematode ◽  
Host Parasite Interactions ◽  
Reproductive Response ◽  
Host Parasite ◽  
Trematode Parasites

AbstractParasitic castration of bivalves by trematodes is common, and may significantly reduce the reproductive capacity of ecologically important species. Understanding the intensity of infection is desirable, as it can indicate the time that has passed since infection, and influence the host's physiological and reproductive response. In addition, it is useful to know the developmental stage of the trematode, to understand trematode population trends and reproductive success. However, most existing methods (e.g. visually estimating the degree of infection) to assess intensity are approximate only and not reproducible. Here, we present a method to accurately quantify the percentage of bivalve gonad filled with digenean trematode tissue, based on small squashes of gonad tissue rapidly photographed under light microscopy. A maximum of 15 photographs is required to determine the percentage of the whole gonad occupied by trematodes with a minimum of 90% confidence, with smaller mussels requiring fewer. In addition, the stage of trematode infection can be assessed because full sporocysts, spent sporocysts and free cercariae are clearly distinguishable. Although variation exists in the distribution of trematodes in gonad tissue, and thus in the estimate of percentage of the gonad filled with trematodes, this method represents a marked improvement on current coarse assessments of infection which typically focus on binary presence/absence measures. This technique can be used to facilitate a more sophisticated understanding of host–parasite interactions in bivalves, and can inform the conservation and reproductive biology of environmentally crucial species.

Numerical and functional responses of intestinal helminths in three rajid skates: evidence for competition between parasites?

Parasitology ◽  
2012 ◽  
Vol 139 (13) ◽  
pp. 1784-1793 ◽  
Author(s):  
HASEEB S. RANDHAWA
Keyword(s):  
Linear Models ◽  
Niche Breadth ◽  
Specific Interactions ◽  
Intestinal Helminths ◽  
Functional Responses ◽  
Intensity Of Infection ◽  
Host Parasite Interactions ◽  
Niche Shifts ◽  
Host Parasite ◽  
Number Of Individuals

SUMMARYHost-parasite interactions generally involve communities of parasites. Within these communities, species will co-exist and/or interact with one another in a manner either benefiting the species involved or to the detriment of one or more of the species. At the level of helminth infracommunities, evidence for intra- and inter-specific competition includes numerical responses, i.e. those regulating helminth intensity of infection, and functional responses, i.e. where the presence of competitors modifies the realised niche of infrapopulations. The objectives of this study are to assess the numerical and functional responses of helminths in infracommunities from 3 rajid skates using general linear models. Despite a lack of numerical responses, functional responses to intra- and inter-specific interactions were observed. A positive correlation between the number of individuals in an infrapopulation and its niche breadth (functional response) was observed for the tapewormsPseudanthobothriumspp. andEcheneibothriumspp., in all their respective hosts, and for the nematodePseudanisakissp. in the little skate. Evidence for inter-specific competition includes niche shifts inPseudanthobothrium purtoni(exlittle skate) andPseudanisakissp. (exthorny skate) in the presence ofPseudanisakissp. and the tapewormGrillotiasp., respectively. These results are consistent with other studies in providing evidence for competition between helminths of skates.

EFFECTS OF CROWDING ON SUPLHURETYLENCHUS SPP. (NEMATODA: ALLANTONEMATIDAE) IN THE HAEMOCOEL OF THEIR BARK BEETLE HOSTS (COLEOPTERA: SCOLYTIDAE)

1989 ◽  
Vol 121 (9) ◽  
pp. 821-822
Author(s):  
Marek Tomalak ◽  
Harold E. Welch ◽  
Terry D. Galloway
Keyword(s):  
Bark Beetle ◽  
Bark Beetles ◽  
Biological Control Agents ◽  
Infection Rates ◽  
Intensity Of Infection ◽  
Nematode Parasites ◽  
Host Parasite Interactions ◽  
Host Parasite ◽  
The Relationship ◽  
Growth And Reproduction

Nematode parasites of bark beetles are taxonomically diverse, and may, in some cases, cause serious pathological and behavioural changes in their hosts (Kaya 1984). Their potential as biological control agents has long been recognized, but to date there is a shortage of elementary information on host-parasite interactions. Though the effects of superparasitism and subsequent crowding on the parasite have been studied for some mermithids (Petersen 1972) and steinernematids (Sandner and Stanuszek 1971), no such observations have been reported for bark beetle parasites. During a survey of nematode parasites of bark beetles in Manitoba, we encountered two examples where nematodes were detrimentally affected at the higher infection rates observed. It was our objective, therefore, to examine the relationship between intensity of infection, and impact on growth and reproduction of the parasites.

Host parasite interactions and pathophysiology in Giardia infections

2011 ◽  
Vol 41 (9) ◽  
pp. 925-933 ◽  
Author(s):  
James A. Cotton ◽  
Jennifer K. Beatty ◽  
Andre G. Buret
Keyword(s):  
Host Parasite Interactions ◽  
Host Parasite

scholarly journals Spatial expression pattern of serine proteases in the blood fluke Schistosoma mansoni determined by fluorescence RNA in situ hybridization

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Lenka Ulrychová ◽  
Pavel Ostašov ◽  
Marta Chanová ◽  
Michael Mareš ◽  
Martin Horn ◽  
...  
Keyword(s):  
In Situ Hybridization ◽  
Schistosoma Mansoni ◽  
Rna Sequencing ◽  
Serine Proteases ◽  
Expression Patterns ◽  
High Sensitivity ◽  
Host Parasite Interactions ◽  
Highly Sensitive ◽  
Host Parasite

Abstract Background The blood flukes of genus Schistosoma are the causative agent of schistosomiasis, a parasitic disease that infects more than 200 million people worldwide. Proteases of schistosomes are involved in critical steps of host–parasite interactions and are promising therapeutic targets. We recently identified and characterized a group of S1 family Schistosoma mansoni serine proteases, including SmSP1 to SmSP5. Expression levels of some SmSPs in S. mansoni are low, and by standard genome sequencing technologies they are marginally detectable at the method threshold levels. Here, we report their spatial gene expression patterns in adult S. mansoni by the high-sensitivity localization assay. Methodology Highly sensitive fluorescence in situ RNA hybridization (FISH) was modified and used for the localization of mRNAs encoding individual SmSP proteases (including low-expressed SmSPs) in tissues of adult worms. High sensitivity was obtained due to specifically prepared tissue and probes in combination with the employment of a signal amplification approach. The assay method was validated by detecting the expression patterns of a set of relevant reference genes including SmCB1, SmPOP, SmTSP-2, and Sm29 with localization formerly determined by other techniques. Results FISH analysis revealed interesting expression patterns of SmSPs distributed in multiple tissues of S. mansoni adults. The expression patterns of individual SmSPs were distinct but in part overlapping and were consistent with existing transcriptome sequencing data. The exception were genes with significantly low expression, which were also localized in tissues where they had not previously been detected by RNA sequencing methods. In general, SmSPs were found in various tissues including reproductive organs, parenchymal cells, esophagus, and the tegumental surface. Conclusions The FISH-based assay provided spatial information about the expression of five SmSPs in adult S. mansoni females and males. This highly sensitive method allowed visualization of low-abundantly expressed genes that are below the detection limits of standard in situ hybridization or by RNA sequencing. Thus, this technical approach turned out to be suitable for sensitive localization studies and may also be applicable for other trematodes. The results suggest that SmSPs may play roles in diverse processes of the parasite. Certain SmSPs expressed at the surface may be involved in host–parasite interactions. Graphic abstract

scholarly journals Urogenital Schistosomiasis—History, Pathogenesis, and Bladder Cancer

2021 ◽  
Vol 10 (2) ◽  
pp. 205
Author(s):  
Lúcio Lara Santos ◽  
Júlio Santos ◽  
Maria João Gouveia ◽  
Carina Bernardo ◽  
Carlos Lopes ◽  
...  
Keyword(s):  
Schistosoma Haematobium ◽  
Historical Perspective ◽  
Hiv Transmission ◽  
Parasite Infection ◽  
Urogenital Schistosomiasis ◽  
Host Parasite Interactions ◽  
Immunodeficiency Virus ◽  
Recent Outbreak ◽  
Host Parasite ◽  
Female Genital

Schistosomiasis is the most important helminthiasis worldwide in terms of morbidity and mortality. Most of the infections occurs in Africa, which about two thirds are caused by Schistosoma haematobium. The infection with S. haematobium is considered carcinogenic leading to squamous cell carcinoma (SCC) and urothelial carcinoma of the urinary bladder. Additionally, it is responsible for female genital schistosomiasis leading to infertility and higher risk of human immunodeficiency virus (HIV) transmission. Remarkably, a recent outbreak in Corsica (France) drew attention to its potential re-mergence in Southern Europe. Thus far, little is known related to host-parasite interactions that trigger carcinogenesis. However, recent studies have opened new avenues to understand mechanisms on how the parasite infection can lead cancer and other associated pathologies. Here, we present a historical perspective of schistosomiasis, and review the infection-associated pathologies and studies on host–parasite interactions that unveil tentative mechanisms underlying schistosomiasis-associated carcinogenesis.

Network Analysis: Ten Years Shining Light on Host–Parasite Interactions

2021 ◽  
Vol 37 (5) ◽  
pp. 445-455
Author(s):  
Rogini Runghen ◽  
Robert Poulin ◽  
Clara Monlleó-Borrull ◽  
Cristina Llopis-Belenguer
Keyword(s):  
Network Analysis ◽  
Host Parasite Interactions ◽  
Host Parasite
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