scholarly journals Roles of three putative salmon louse (Lepeophtheirus salmonis) prostaglandin E2 synthases in physiology and host–parasite interactions

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Sussie Dalvin ◽  
Christiane Eichner ◽  
Michael Dondrup ◽  
Aina-Cathrine Øvergård

Abstract Background The salmon louse (Lepeophtheirus salmonis) is a parasite of salmonid fish. Atlantic salmon (Salmo salar) exhibit only a limited and ineffective immune response when infested with this parasite. Prostaglandins (PGs) have many biological functions in both invertebrates and vertebrates, one of which is the regulation of immune responses. This has led to the suggestion that prostaglandin E2 (PGE2) is important in the salmon louse host–parasite interaction, although studies of a salmon louse prostaglandin E2 synthase (PGES) 2 gene have not enabled conformation of this hypothesis. The aim of the present study was, therefore, to characterize two additional PGES-like genes. Methods Lepeophtheirus salmonis microsomal glutathione S-transferase 1 like (LsMGST1L) and LsPGES3L were investigated by sequencing, phylogenetics, transcript localization and expression studies. Moreover, the function of these putative PGES genes in addition to the previously identified LsPGES2 gene was analyzed in double stranded (ds) RNA-mediated knockdown (KD) salmon louse. Results Analysis of the three putative LsPGES genes showed a rather constitutive transcript level throughout development from nauplius to the adult stages, and in a range of tissues, with the highest levels in the ovaries or gut. DsRNA-mediated KD of these transcripts did not produce any characteristic changes in phenotype, and KD animals displayed a normal reproductive output. The ability of the parasite to infect or modulate the immune response of the host fish was also not affected by KD. Conclusions Salmon louse prostaglandins may play endogenous roles in the management of reproduction and oxidative stress and may be a product of salmon louse blood digestions. Graphic Abstract

2012 ◽  
Vol 4 (1) ◽  
pp. 54-56
Author(s):  
T.S.P. Fernando ◽  
H.K.A.V.A. Kulasena Fernando

Parasitism is a relationship where one of the parties (the parasite) either harms its host or lives at the expense of it. Host parasite interactions are important driving forces in population dynamics and even extinction. These interactions are also indicators of ecosystem health and they are important in stabilizing food webs. A parasite may cause mechanical injury, stimulate a damaging inflammatory or immune response, or simply rob the host of nutrition. However in the wild most parasites must live in harmony with their hosts. If the parasites kill the host, they themselves would ultimately die without shelter and nutrition. Reptiles become hosts to a number of parasitic organisms ranging from protozoans to arthropods. Among these, ticks (hard and soft) are the most common arthropod group that parasitizes reptiles.


2021 ◽  
Vol 12 ◽  
Author(s):  
Yue Yuan ◽  
Jianping Zhao ◽  
Min Chen ◽  
Huifang Liang ◽  
Xin Long ◽  
...  

Schistosomiasis is a parasitic disease endemic to freshwater areas of Southeast Asia, Africa, and South America that is capable of causing serious damage to the internal organs. Recent studies have linked exosomes to the progression of schistosomiasis. These structures are important mediators for intercellular communication, assist cells to exchange proteins, lipids, and genetic material and have been shown to play critical roles during host–parasite interactions. This review aims to discuss the pathophysiology of exosomes in schistosomiasis and their roles in regulating the host immune response. Understanding how exosomes are involved in the pathogenesis of schistosomiasis may provide new perspectives in diagnosing and treating this neglected disease.


2019 ◽  
Author(s):  
Devon Keller ◽  
Devin Kirk ◽  
Pepijn Luijckx

AbstractDespite its pivotal role in evolutionary and ecological processes the genetic architecture underlying host-parasite interactions remains understudied. Here we use a quantitative trait loci approach to identify regions in the Daphnia magna genome that provide resistance against its microsporidium parasite Ordospora colligata. The probability that Daphnia became infected was affected by a single locus and an interaction between two additional loci. A fourth locus influenced the number of spores that grew within the host. Comparing our findings to previously published genetic work on Daphnia magna revealed that two of these loci may be the same as detected for another microsporidium parasite, suggesting a general immune response to this group of pathogens. More importantly, this comparison revealed that two regions previously identified to be under selection coincided with parasite resistance loci, highlighting the pivotal role parasites may play in shaping the host genome.


2012 ◽  
Vol 279 (1741) ◽  
pp. 3234-3240 ◽  
Author(s):  
Alex Best ◽  
Gráinne Long ◽  
Andy White ◽  
Mike Boots

By definition, parasites harm their hosts, but in many infections much of the pathology is driven by the host immune response rather than through direct damage inflicted by parasites. While these immunopathological effects are often well studied and understood mechanistically in individual disease interactions, there remains relatively little understanding of their broader impact on the evolution of parasites and their hosts. Here, we theoretically investigate the implications of immunopathology, broadly defined as additional mortality associated with the host's immune response, on parasite evolution. In particular, we examine how immunopathology acting on different epidemiological traits (namely transmission, virulence and recovery) affects the evolution of disease severity. When immunopathology is costly to parasites, such that it reduces their fitness, for example by decreasing transmission, there is always selection for increased disease severity. However, we highlight a number of host–parasite interactions where the parasite may benefit from immunopathology, and highlight scenarios that may lead to the evolution of slower growing parasites and potentially reduced disease severity. Importantly, we find that conclusions on disease severity are highly dependent on how severity is measured. Finally, we discuss the effect of treatments used to combat disease symptoms caused by immunopathology.


2009 ◽  
Vol 5 (6) ◽  
pp. 721-722
Author(s):  
Jay D. Evans

A conference exploring ‘The impact of the environment on innate immunity: the threat of diseases’ was held on 4–9 May 2009 in Obergurgl, Austria, thanks to the support from the European Science Foundation, Innsbruck University and the Austrian Science Foundation. The goals of the conference were to explore how the outcomes of host–parasite interactions depend on variation across individuals, their parasites and the environment in which they both find themselves. Central themes were the inherent costs of mounting an immune response, the ability of some organisms to pre-empt infection by ‘priming’ their immune systems, the fact that parasites learn to evade immune responses over time and the use of theory to predict when diseases will get out of hand. Many of the systems presented had clear impacts on human health, agriculture or the maintenance of complex ecosystems. There was common ground throughout in developing methodologies and embracing what one of the organizers termed the ‘interactome’ between hosts and those which would exploit them.


Parasitology ◽  
2002 ◽  
Vol 124 (7) ◽  
pp. 165-182 ◽  
Author(s):  
O. TULLY ◽  
D. T. NOLAN

Lepeophtheirus salmonis is a specific parasite of salmonids that occurs in the Atlantic and Pacific Oceans. When infestations are heavy fish mortality can occur although the factors that are responsible for causing epizootics, especially in wild salmonid populations are still largely unknown. Over the past 20 years this parasite has caused significant economic losses in farmed salmon production and possibly in wild salmonid populations locally. Understanding the connectivity between populations is crucial to an understanding of the epidemiology of infections and for management of infections in aquaculture. Data from genetics, pesticide resistance, larval dispersal models and spatial and temporal patterns of infestation in wild and farmed hosts suggests a spatially highly structured metapopulation the components of which have different levels of connectivity, probabilities of extinction and influence on the development of local infestations. The population structure is defined mainly by the dispersal dynamics of the planktonic stages and the behaviour of the host.Until recently virtually nothing was known about the relationship between the parasite and the host, or how the host may influence lice at local or population level. Typically, impacts on the host have usually been reported in terms of pathological lesions caused by attachment and feeding of the adult stages, as well as localised mild epithelial responses to juvenile attachment. However many studies report pathology associated with severe infestation. Recent new studies on the host–parasite interactions of L. salmonis have shown that this parasite induces stress-related responses systemically in the host skin and gills and that the stress response and immune systems are modulated. In the second part of this review, these new studies are presented, together with results from other host–parasite model systems where data for caligid sea lice are missing. One of the most revealing methods reported recently is the application of a net confinement stressor to examine modulation of the stress response and immune system of the host fish. This approach has shown that although until now, infective stages of L. salmonis were not thought to affect the host, they do induce systematic effects in the host that result in a stress response and modulated immune system. Host–parasite interactions affecting these stress responses and the immune system may be key factors in facilitating epizootics by reducing the host's ability to reject the parasites, as well as reducing disease resistance under some environmental conditions. The host–parasite interaction therefore needs to be incorporated into any model of population structure and dynamics.


2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
R. A. Khan

Host-parasite interactions are complex, compounded by factors that are capable of shifting the balance in either direction. The host's age, behaviour, immunological status, and environmental change can affect the association that is beneficial to the host whereas evasion of the host’s immune response favours the parasite. In fish, some infections that induce mortality are age and temperature dependent. Environmental change, especially habitat degradation by anthropogenic pollutants and oceanographic alterations induced by climatic, can influence parasitic-host interaction. The outcome of these associations will hinge on susceptibility and resistance.


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