16 research outputs found
Data from: Host infection history modifies co-infection success of multiple parasite genotypes
1. Co-infections by multiple parasite genotypes are common and have important implications for host-parasite ecology and evolution through within-host interactions. Typically, these infections take place sequentially and therefore, the outcome of co-infection may be shaped by host immune responses triggered by previous infections. For example, in vertebrates specific immune responses play a central role in protection against disease over the course of life, but co-infection research has mostly focused on previously uninfected individuals. 2. Here, we investigated whether sequential exposure and activation of host resistance in rainbow trout Oncorhynchus mykiss affects infection success and interactions between co-infecting parasite genotypes of the trematode eye-fluke Diplostomum pseudospathaceum. 3. In accordance with earlier results, we show that a simultaneous attack of two parasite genotypes facilitates parasite establishment in previously uninfected hosts. However, we find for the first time that this facilitation in co-infection is lost in hosts with prior infection. 4. We conclude that vertebrate host infection history can affect the direction of within-host parasite interactions. Our results may have significant implications for the evolution of co-infections and parasite transmission strategies
Genotypic and phenotypic variation in transmission traits of a complex life cycle parasite
Characterizing genetic variation in parasite transmission traits and its contribution to parasite vigor is essential for understanding the evolution of parasite lifeâhistory traits. We measured genetic variation in output, activity, survival, and infection success of clonal transmission stages (cercaria larvae) of a complex life cycle parasite (Diplostomum pseudospathaceum). We further tested if variation in host nutritional stage had an effect on these traits by keeping hosts on limited or ad libitum diet. The traits we measured were highly variable among parasite genotypes indicating significant genetic variation in these lifeâhistory traits. Traits were also phenotypically variable, for example, there was significant variation in the measured traits over time within each genotype. However, host nutritional stage had no effect on the parasite traits suggesting that a shortâterm reduction in host resources was not limiting the cercarial output or performance. Overall, these results suggest significant interclonal and phenotypic variation in parasite transmission traits that are not affected by host nutritional status.ISSN:2045-775
Data from: Interactions among bacterial strains and fluke genotypes shape virulence of co-infection
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 effects of genotype by genotype (GĂG) interactions between unrelated parasite species on virulence of co infection is limited. Here we tested such 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 to 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 GĂG 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
Louhi et al. Original data
Original data from the experimental exposure of fish to Flavobacterium columnare and Diplostomum pseudospathaceum. The data present survival times (hours) and numbers of Diplostomum in the eye lenses for fish in single flavobacterial infections (strains 1-6), single Diplostomum infections (genotypes a-e), and in all pairwise co-infection combinations of the strains and genotypes
Reciprocal interaction matrix reveals complex genetic and dose-dependent specificity among coinfecting parasites
Understanding genetic specificity in factors determining
the outcome of host-parasite interactions is especially important as
it contributes to parasite epidemiology, virulence, and maintenance
of genetic variation. Such specificity, however, is still generally poorly
understood. We examined genetic specificity in interactions among
coinfecting parasites. In natural populations, individual hosts are
often simultaneously infected by multiple parasite species and genotypes
that interact. Such interactions could maintain genetic variation
in parasite populations if they are genetically specific so that
the relative fitness of parasite genotypes varies across host individuals
depending on (1) the presence/absence of coinfections and/or (2)
the genetic composition of the coinfecting parasite community. We
tested these predictions using clones of fish eye flukes Diplostomum
pseudospathaceum and Diplostomum gasterostei. We found that interactions
among parasites had a strong genetic basis and that this
modified genetic variation in infection success of D. pseudospathaceum
between single and multiple infections as well as across multiply
infected host individuals depending on the genetic identity of the
coinfecting D. gasterostei. The relative magnitude of these effects,
however, depended on the exposure dose, suggesting that ecological
factors can modify genetic interactions between parasites.peerReviewe
Data from: Reciprocal interaction matrix reveals complex genetic and dose-dependent specificity among coinfecting parasites
Understanding genetic specificity in factors determining the outcome of host-parasite interactions is especially important as it contributes to parasite epidemiology, virulence, and maintenance of genetic variation. Such specificity, however, is still generally poorly understood. We examined genetic specificity in interactions among coinfecting parasites. In natural populations, individual hosts are often simultaneously infected by multiple parasite species and genotypes that interact. Such interactions could maintain genetic variation in parasite populations if they are genetically specific so that the relative fitness of parasite genotypes varies across host individuals depending on (1) the presence/absence of coinfections and/or (2) the genetic composition of the coinfecting parasite community. We tested these predictions using clones of fish eye flukes Diplostomum pseudospathaceum and Diplostomum gasterostei. We found that interactions among parasites had a strong genetic basis and that this modified genetic variation in infection success of D. pseudospathaceum between single and multiple infections as well as across multiply infected host individuals depending on the genetic identity of the coinfecting D. gasterostei. The relative magnitude of these effects, however, depended on the exposure dose, suggesting that ecological factors can modify genetic interactions between parasites