scholarly journals Interactions among bacterial strains and fluke genotypes shape virulence of co-infection

2015 ◽  
Vol 282 (1821) ◽  
pp. 20152097 ◽  
Author(s):  
Katja-Riikka Louhi ◽  
Lotta-Riina Sundberg ◽  
Jukka Jokela ◽  
Anssi Karvonen
Keyword(s):  
Evolutionary Dynamics ◽  
Parasite Species ◽  
Bacterial Strains ◽  
Parasite Fitness ◽  
Host Parasite Interactions ◽  
Host Health ◽  
Infection Focus ◽  
Host Mortality ◽  
Host Parasite ◽  
Virulent Parasite

Most studies of virulence of infection focus on pairwise host–parasite interactions. However, hosts are almost universally co-infected by several parasite strains and/or genotypes of the same or different species. While theory predicts that co-infection favours more virulent parasite genotypes through intensified competition for host resources, knowledge of the effects of genotype by genotype (G × G) interactions between unrelated parasite species on virulence of co-infection is limited. Here, we tested such a relationship by challenging rainbow trout with replicated bacterial strains and fluke genotypes both singly and in all possible pairwise combinations. We found that virulence (host mortality) was higher in co-infections compared with single infections. Importantly, we also found that the overall virulence was dependent on the genetic identity of the co-infecting partners so that the outcome of co-infection could not be predicted from the respective virulence of single infections. Our results imply that G × G interactions among co-infecting parasites may significantly affect host health, add to variance in parasite fitness and thus influence evolutionary dynamics and ecology of disease in unexpected ways.

scholarly journals Functional genomics of simian malaria parasites and host–parasite interactions

2019 ◽  
Vol 18 (5) ◽  
pp. 270-280 ◽  
Author(s):  
Mary R Galinski
Keyword(s):  
Functional Genomics ◽  
Malaria Parasite ◽  
Parasite Species ◽  
Plasmodium Knowlesi ◽  
New World Monkeys ◽  
Malaria Parasites ◽  
Zoonotic Infections ◽  
Simian Malaria ◽  
Host Parasite Interactions ◽  
Host Parasite

AbstractTwo simian malaria parasite species, Plasmodium knowlesi and Plasmodium cynomolgi, cause zoonotic infections in Southeast Asia, and they have therefore gained recognition among scientists and public health officials. Notwithstanding, these species and others including Plasmodium coatneyi have served for decades as sources of knowledge on the biology, genetics and evolution of Plasmodium, and the diverse ramifications and outcomes of malaria in their monkey hosts. Experimental analysis of these species can help to fill gaps in knowledge beyond what may be possible studying the human malaria parasites or rodent parasite species. The genome sequences for these simian malaria parasite species were reported during the last decade, and functional genomics research has since been pursued. Here research on the functional genomics analysis involving these species is summarized and their importance is stressed, particularly for understanding host–parasite interactions, and potentially testing novel interventions. Importantly, while Plasmodium falciparum and Plasmodium vivax can be studied in small New World monkeys, the simian malaria parasites can be studied more effectively in the larger Old World monkey macaque hosts, which are more closely related to humans. In addition to ex vivo analyses, experimental scenarios can include passage through Anopheline mosquito hosts and longitudinal infections in monkeys to study acute and chronic infections, as well as relapses, all in the context of the in vivo host environment. Such experiments provide opportunities for understanding functional genomic elements that govern host–parasite interactions, immunity and pathogenesis in-depth, addressing hypotheses not possible from in vitro cultures or cross-sectional clinical studies with humans.

Co-evolution between mosquitoes and microsporidian transmission strategies

2018 ◽  
Author(s):  
◽  
Giacomo Zilio
Keyword(s):  
Evolutionary Dynamics ◽  
Horizontal Transmission ◽  
Life History Evolution ◽  
Induced Response ◽  
Ecological Conditions ◽  
Transmission Strategy ◽  
Host Parasite Interactions ◽  
Key Aspects ◽  
Host Parasite ◽  
The Impact

Parasite and host impose strong selection on each other. The first causes damages and mortality to the host, while the second responds by reducing the detrimental effects and the intensity and/or success of infection. The resulting co-evolutionary dynamics are profoundly affected by the ecological conditions, for these may influence many aspects of host-parasite interactions including life history evolution, virulence and transmission. It is therefore essential to study and incorporate environmental variation in the field of parasitology to gain an exhaustive understanding of how host and parasite evolve. In this thesis, a single generation and an evolutionary experimental approach were used to investigate the impact of the ecological and epidemiological conditions on several aspects of host-parasite interactions, with the main focus on parasite transmission strategies. Firstly, it was examined the effect of the availability of resources for the host, timing of infection, and co-infection on the virulence and transmission success of two parasites with conflicting transmission strategy. Next, it was tested how the environment influenced the trade-off between vertical and horizontal transmission in a parasite with a mixed mode of transmission and it was assessed the genetic contribution of the host to its transmission mode. Whether the vertical and horizontal component of this parasite and the associated virulence responded to restriction opportunities, represented by different availability of resources over several generations, was investigated with an evolutionary experiment. Finally, the presence of a plastically parasite-induced response on the recombination rate of the host as a potential cross-generational defence mechanism was explored. The experiments cover many key aspects of host-parasite interactions and emphasize the role of the ecological conditions on shaping these relationships. The results and their implications are discussed in detail throughout the thesis. Overall, this work highlights the dependence of crucial aspects of host-parasite interactions from the epidemiological and ecological conditions. Disentangling the various forces surrounding these interactions may help us to acquire a better knowledge of how a changing environment may drive the evolution of both host and parasite.

scholarly journals Immune defence, parasite evasion strategies and their relevance for ‘macroscopic phenomena’ such as virulence

2008 ◽  
Vol 364 (1513) ◽  
pp. 85-98 ◽  
Author(s):  
Paul Schmid-Hempel
Keyword(s):  
Immune Evasion ◽  
Life History Theory ◽  
Evolutionary Ecology ◽  
Parasite Clearance ◽  
Multiple Infections ◽  
Parasite Fitness ◽  
Host Parasite Interactions ◽  
Evolution Of Virulence ◽  
Host Parasite ◽  
Insight Into

The discussion of host–parasite interactions, and of parasite virulence more specifically, has so far, with a few exceptions, not focused much attention on the accumulating evidence that immune evasion by parasites is not only almost universal but also often linked to pathogenesis, i.e. the appearance of virulence. Now, the immune evasion hypothesis offers a deeper insight into the evolution of virulence than previous hypotheses. Sensitivity analysis for parasite fitness and life-history theory shows promise to generate a more general evolutionary theory of virulence by including a major element, immune evasion to prevent parasite clearance from the host. Also, the study of dose–response relationships and multiple infections should be particularly illuminating to understand the evolution of virulence. Taking into account immune evasion brings immunological processes to the core of understanding the evolution of parasite virulence and for a range of related issues such as dose, host specificity or immunopathology. The aim of this review is to highlight the mechanism underlying immune evasion and to discuss possible consequences for the evolutionary ecology analysis of host–parasite interactions.

scholarly journals Characterization of vertically and cross-species transmitted viruses in the cestode parasite Schistocephalus solidus

2019 ◽  
Author(s):  
Megan A Hahn ◽  
Karyna Rosario ◽  
Pierrick Lucas ◽  
Nolwenn M Dheilly
Keyword(s):  
Evolutionary Dynamics ◽  
Broad Distribution ◽  
Parasite Fitness ◽  
Virus Diversity ◽  
Cestode Parasite ◽  
Schistocephalus Solidus ◽  
Host Parasite ◽  
The Impact

AbstractParasitic flatworms (Neodermata) represent a public health and economic burden due to associated debilitating diseases and limited therapeutic treatments available. Despite their importance, there is scarce information regarding flatworm-associated microbes. We report the discovery of six RNA viruses in the cestode Schistocephalus solidus. None were closely related to classified viruses and they represent new taxa. Mining transcriptomic data revealed the broad distribution of these viruses in Alaskan and European S. solidus populations. We demonstrate through in vitro culture of S. solidus that five of these viruses are vertically transmitted. With experimental infections and field-sampling, we show that one of the viruses is transmitted to parasitized hosts. The impact of these viruses in parasite fitness and pathogenicity, and in host-parasite co-evolutionary dynamics remains to be determined. The detection of six novel viruses in this first characterization of viruses in Neodermatans likely represents a fraction of virus diversity in parasitic flatworms.

scholarly journals The evolution of host protection by vertically transmitted parasites

2010 ◽  
Vol 278 (1707) ◽  
pp. 863-870 ◽  
Author(s):  
Edward O. Jones ◽  
Andrew White ◽  
Michael Boots
Keyword(s):  
Death Rate ◽  
Parasite Species ◽  
Selective Force ◽  
Host Protection ◽  
Host Parasite Interactions ◽  
High Virulence ◽  
Host Parasite ◽  
Selective Effects

Hosts are often infected by a variety of different parasites, leading to competition for hosts and coevolution between parasite species. There is increasing evidence that some vertically transmitted parasitic symbionts may protect their hosts from further infection and that this protection may be an important reason for their persistence in nature. Here, we examine theoretically when protection is likely to evolve and its selective effects on other parasites. Our key result is that protection is most likely to evolve in response to horizontally transmitted parasites that cause a significant reduction in host fecundity. The preponderance of sterilizing horizontally transmitted parasites found in arthropods may therefore explain the evolution of protection seen by their symbionts. We also find that protection is more likely to evolve in response to highly transmissible parasites that cause intermediate, rather than high, virulence (increased death rate when infected). Furthermore, intermediate levels of protection select for faster, more virulent horizontally transmitted parasites, suggesting that protective symbionts may lead to the evolution of more virulent parasites in nature. When we allow for coevolution between the symbiont and the parasite, more protection is likely to evolve in the vertically transmitted symbionts of longer lived hosts. Therefore, if protection is found to be common in nature, it has the potential to be a major selective force on host–parasite interactions.

scholarly journals Coccidia-Microbiota Interactions and Their Effects on the Host

2021 ◽  
Vol 11 ◽  
Author(s):  
Chenyang Lu ◽  
Yaqun Yan ◽  
Fuchun Jian ◽  
Changshen Ning
Keyword(s):  
Gut Microbiota ◽  
Intestinal Tract ◽  
Parasite Species ◽  
Clinical Symptoms ◽  
Parasitic Infections ◽  
Host Interactions ◽  
Host Parasite Interactions ◽  
Two Factors ◽  
Host Parasite ◽  
And Control

As a common parasitic disease in animals, coccidiosis substantially affects the health of the host, even in the absence of clinical symptoms and intestinal tract colonization. Gut microbiota is an important part of organisms and is closely related to the parasite and host. Parasitic infections often have adverse effects on the host, and their pathogenic effects are related to the parasite species, parasitic site and host-parasite interactions. Coccidia-microbiota-host interactions represent a complex network in which changes in one link may affect the other two factors. Furthermore, coccidia-microbiota interactions are not well understood and require further research. Here, we discuss the mechanisms by which coccidia interact directly or indirectly with the gut microbiota and the effects on the host. Understanding the mechanisms underlying coccidia-microbiota-host interactions is important to identify new probiotic strategies for the prevention and control of coccidiosis.

scholarly journals Fitness costs of disrupting circadian rhythms in malaria parasites

2011 ◽  
Vol 278 (1717) ◽  
pp. 2429-2436 ◽  
Author(s):  
Aidan J. O'Donnell ◽  
Petra Schneider ◽  
Harriet G. McWatters ◽  
Sarah E. Reece
Keyword(s):  
Circadian Rhythms ◽  
Parasite Species ◽  
Biological Rhythms ◽  
Cell Cycles ◽  
Transmission Potential ◽  
Host Parasite Interactions ◽  
Adaptive Value ◽  
Widespread Phenomenon ◽  
Fitness Benefits ◽  
Host Parasite

Circadian biology assumes that biological rhythms maximize fitness by enabling organisms to coordinate with their environment. Despite circadian clocks being such a widespread phenomenon, demonstrating the fitness benefits of temporal coordination is challenging and such studies are rare. Here, we tested the consequences—for parasites—of being temporally mismatched to host circadian rhythms using the rodent malaria parasite, Plasmodium chabaudi . The cyclical nature of malaria infections is well known, as the cell cycles across parasite species last a multiple of approximately 24 h, but the evolutionary explanations for periodicity are poorly understood. We demonstrate that perturbation of parasite rhythms results in a twofold cost to the production of replicating and transmission stages. Thus, synchronization with host rhythms influences in-host survival and between-host transmission potential, revealing a role for circadian rhythms in the evolution of host–parasite interactions. More generally, our results provide a demonstration of the adaptive value of circadian rhythms and the utility of using an evolutionary framework to understand parasite traits.

scholarly journals Changes in native and introduced host–parasite networks

2021 ◽  
Author(s):  
Mar Llaberia-Robledillo ◽  
Juan Antonio Balbuena ◽  
Volodimir Sarabeev ◽  
Cristina Llopis-Belenguer
Keyword(s):  
Network Analysis ◽  
Sea Of Japan ◽  
Parasite Species ◽  
The Sea Of Japan ◽  
Helminth Parasites ◽  
Interaction Patterns ◽  
Sea Of Azov ◽  
Native Community ◽  
Host Parasite Interactions ◽  
Host Parasite

AbstractIntroduced species can alter the dynamics and structure of a native community. Network analysis provides a tool to study host–parasite interactions that can help to predict the possible impact of biological invasions or other disturbances. In this study, we used weighted bipartite networks to assess differences in the interaction patterns between hosts and helminth parasites of native (Sea of Japan) and invasive (Black Sea and Sea of Azov) populations of Planiliza haematocheilus (Teleostei: Mugilidae). We employed three quantitative network descriptors, connectance, weighted nestedness and modularity, to gain insight into the structure of the host–parasite networks in the native and invaded areas. The role of parasite species in the networks was assessed using the betweenness centrality index. We analyzed networks encompassing the whole helminth community and subsets of species classified by their transmission strategy. The analyses were downscaled to host individual-level to consider intraspecific variation in parasite communities. We found significant differences between networks in the native and invaded areas. The latter presented a higher value of nestedness, which may indicate a co-occurrence between parasite species with many connections in the network and species with fewer interactions within the same individual-host. In addition, modularity was higher in the native area’s networks than those of the invaded area, with subgroups of host individuals that interact more frequently with certain parasite species than with others. Only the networks composed of actively transmitted parasites and ectoparasites did not show significant differences in modularity between the Sea of Azov and the Sea of Japan, which could be due to the introduction of a part of the native community into the invaded environment, with a lower diversity and abundance of species. We show that network analysis provides a valuable tool to illuminate the changes that occur in host–parasite interactions when an invasive species and its parasite community are introduced into a new area.

Fitness and virulence of a bacterial endoparasite in an environmentally stressed crustacean host

Parasitology ◽  
2010 ◽  
Vol 138 (1) ◽  
pp. 122-131 ◽  
Author(s):  
ANJA COORS ◽  
LUC DE MEESTER
Keyword(s):  
Environmental Pollutants ◽  
Somatic Growth ◽  
Parasite Development ◽  
Predation Threat ◽  
Host Condition ◽  
Parasite Fitness ◽  
Host Parasite Interactions ◽  
Fish Kairomone ◽  
Host Parasite ◽  
Crustacean Host

SUMMARYHost-parasite interactions are shaped by the co-evolutionary arms race of parasite virulence, transmission success as well as host resistance and recovery. The virulence and fitness of parasites may depend on host condition, which is mediated, for instance, by host energy constraints. Here, we investigated to what extent stress imposed by predation threat and environmental pollutants influences host-parasite interactions. We challenged the crustacean hostDaphnia magnawith the sterilizing bacterial endoparasitePasteuria ramosaand simultaneously exposed the host to fish kairomones, the pesticide carbaryl or both stressors. While parasite virulence, measured as impact on host mortality and sterilization, increased markedly after short-term pesticide exposure, it was not influenced by predation threat. Parasite fitness, measured in terms of produced transmission stages, decreased both in fish and pesticide treatments. This effect was much stronger under predation threat than carbaryl exposure, and was attributable to reduced somatic growth of the host, presumably resulting in fewer resources for parasite development. While the indirect impact of both stressors on spore loads provides evidence for host condition-dependent parasite fitness, the finding of increased virulence only under carbaryl exposure indicates a stronger physiological impact of the neurotoxic chemical compared with the effect of a non-toxic fish kairomone.

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