scholarly journals Changes in native and introduced host–parasite networks

Author(s):  
Mar Llaberia-Robledillo ◽  
Juan Antonio Balbuena ◽  
Volodimir Sarabeev ◽  
Cristina Llopis-Belenguer

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.

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

Parasitology ◽  
1989 ◽  
Vol 99 (S1) ◽  
pp. S59-S79 ◽  
Author(s):  
R. M. Anderson ◽  
R. M. May ◽  
S. Gupta

SUMMARYThe paper examines non-linear dynamical phenomena in host—parasite interactions by reference to a series of different problems ranging from the impact on transmission of control measures based on vaccination and chemotherapy, to the effects of immunological responses targeted at different stages in a parasite's life-cycle. Throughout, simple mathematical models are employed to aid in interpretation. Analyses reveal that the influence of a defined control measure on the prevalence or intensity of infection, whether vaccination or drug treatment, is non-linearly related to the magnitude of control effort (as defined by the proportion of individuals vaccinated or treated with a drug). Consideration of the relative merits of gametocyte and sporozoite vaccines against malarial parasites suggests that very high levels of cohort immunization will be required to block transmission in endemic areas, with the former type of vaccine being more effective in reducing transmission for a defined level of coverage and the latter being better with respect to a reduction in morbidity. The inclusion of genetic elements in analyses of the transmission of helminth parasites reveals complex non-linear patterns of change in the abundance of different parasite genotypes under selection pressures imposed by either the host immunological defences or the application of chemotherapeutic agents. When resistance genes are present in parasite populations, the degree to which abundance can be suppressed by chemotherapy depends critically on the frequency and intensity of application, with intermediate values of the former being optimal. A more detailed consideration of the impact of immunological defences on parasite population growth within an individual host, by reference to the erythrocytic cycle of malaria, suggests that the effectiveness of a given immunological response is inversely related to the life-expectancy of the target stage in the parasite's developmental cycle.


Zootaxa ◽  
2007 ◽  
Vol 1434 (1) ◽  
pp. 27 ◽  
Author(s):  
J. FALCÓN-ORDAZ ◽  
J. C. WINDFIELD-PÉREZ ◽  
B. MENDOZA-GARFIAS ◽  
G. PARRA-OLEA ◽  
G. PÉREZ-PONCE DE LEÓN

Plethodontid salamanders represent a group of amphibians that show a great evolutionary diversification in México, however no study of their helminth parasites had been conducted thus far. In this paper, we describe Cosmocerca acanthurum n. sp. (Nematoda: Cosmocercidae) from the intestine of the plethodontid salamanders Pseudoeurycea leprosa and Chiropterotriton orculus from Llano Grande and Texcalyacac, Estado de México, in Central México. Cosmocerca acanthurum n. sp. is easily distinguished from all other species of Cosmocerca in that females possess a uniquely spined tail, a character no seen in congeners. In addition, we compiled all the information of helminth parasites of plethodontid salamanders, and we present it in the form of a checklist of both parasite-host, and host-parasite. A brief analysis of the helminth parasite species composition is presented regarding life-history and development characteristics of plethodontids.


2019 ◽  
Vol 18 (5) ◽  
pp. 270-280 ◽  
Author(s):  
Mary R Galinski

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.


2015 ◽  
Vol 282 (1821) ◽  
pp. 20152097 ◽  
Author(s):  
Katja-Riikka Louhi ◽  
Lotta-Riina Sundberg ◽  
Jukka Jokela ◽  
Anssi Karvonen

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.


Zootaxa ◽  
2008 ◽  
Vol 1721 (1) ◽  
pp. 1 ◽  
Author(s):  
FABIANO M. VIEIRA ◽  
JOSÉ L. LUQUE ◽  
LUIS C. MUNIZ-PEREIRA

Ninety-five helminth parasite species totaling 480 records (including 60 new host and geographical records) in 21 species of wild carnivore mammals from Brazil were listed. Nineteen undetermined helminth species and 4 undetermined host species were also included. Information about the site of infection of parasites, localities, references and a host-parasite list were included herein.


2010 ◽  
Vol 278 (1707) ◽  
pp. 863-870 ◽  
Author(s):  
Edward O. Jones ◽  
Andrew White ◽  
Michael Boots

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.


Author(s):  
Chenyang Lu ◽  
Yaqun Yan ◽  
Fuchun Jian ◽  
Changshen Ning

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.


2011 ◽  
Vol 278 (1717) ◽  
pp. 2429-2436 ◽  
Author(s):  
Aidan J. O'Donnell ◽  
Petra Schneider ◽  
Harriet G. McWatters ◽  
Sarah E. Reece

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.


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