Virulence evolution during a naturally occurring parasite outbreak

Gowler, Camden D.; Essington, Haley; O’Brien, Bruce; Shaw, Cheng-Kuang; Bilich, Rebecca; Clay, P. A.; Duffy, Meghan A.

doi:10.1007/s10682-022-10169-6

Cited by 7 publications

(7 citation statements)

References 55 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In new areas with new host species or populations, a parasite must choose an optimal level of virulence to maximise its reproduction success [ 17 , 18 ]. In this situation, high virulence reduces the host’s fitness as well as its lifespan, which threaten the survival of the parasite and can drive the extinction of the whole parasite population.…”

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Hatchability of Fascioloides magna Eggs in Cervids

et al. 2023

View full text Add to dashboard Cite

The giant liver fluke (Fascioloides magna) is an invasive parasite found permanently in three foci in Europe. The fluke has an indirect life cycle involving a final and an intermediate host. The currently accepted terminology determines three types of final hosts: definitive, dead-end, and aberrant hosts. Recently, roe deer (Capreolus capreolus) has been classified as an aberrant host, which cannot contribute to the reproduction of F. magna. This study investigated the hatchability of F. magna eggs of red deer (Cervus elaphus) and roe deer origin to compare the suitability of the two host species for the maintenance of the parasite. The study was carried out on a newly invaded area, two years after the first reported observation of F. magna. The prevalence of the parasite proved to be 68.4% (CI95% 44.6–85.3%) in red deer and 36.7% (CI95% 24.8–50.0%) in roe deer. The difference between the two species was confirmed to be significant (p = 0.02). The mean intensity proved to be 10.0 (CI95% 4.9–22.6) and 7.59 (CI95% 2.7–24.2) in the red deer and the roe deer, respectively. The difference of the mean intensities did not prove to be significant (p = 0.72). Of the 70 observed pseudocysts, 67 originated from red deer and 3 from roe deer. Most of the pseudocysts contained two flukes, while a few pseudocysts contained one or three parasites. Egg production was observed in all three types of pseudocysts. We did not find more than three flukes in any pseudocyst. The apparent proportion of self-fertilisation in flukes without mating partners was 23.5% and 100% in red deer and roe deer, respectively. The survival of single-parent eggs was not confirmed to be worse than that of gregarious parents. The viability of offspring originating from roe and red deer differed significantly. Our findings suggest that F. magna adapted to the new populations of susceptible hosts rather than vice versa.

show abstract

Section: Discussionmentioning

confidence: 99%

“…In this situation, high virulence reduces the host’s fitness as well as its lifespan, which threaten the survival of the parasite and can drive the extinction of the whole parasite population. The reduction in virulence in favour of better transmissibility can be observed in many parasite species [ 17 , 18 , 19 , 20 ].…”

Section: Discussionmentioning

confidence: 99%

Hatchability of Fascioloides magna Eggs in Cervids

et al. 2023

View full text Add to dashboard Cite

show abstract

“…Additional ecological factors such as predation could also influence parasite evolution in this system. It is noteworthy that Gowler et al (2022) documented that P. ramosa evolved reduced spore production during this same epidemic in Little Appleton, potentially due to the selective pressure to shift from vegetative growth to the production of transmission spores earlier (thus generating fewer spores) in a likely high predation environment. Future studies that track whether epidemic size is generally associated with parasite genetic diversity, and whether those patterns are modulated by factors such as predation, would be very valuable, particularly since our study had only two populations.…”

Section: Ta B L Ementioning

confidence: 99%

“…Although there is phenotypic evidence that P. ramosa evolution occurs over the course of outbreaks (Auld et al, 2014;Gowler et al, 2022;Paplauskas et al, 2021), we did not know how parasite genotype assemblages would change within outbreaks. Parasite genotypic diversity could increase as mutations occur, decrease if parasites adapt to low-diversity host populations, or be maintained if different genotypes are favored through time due to negative frequency-dependent selection and/or by migration from other lakes or reintroduction from the spore bank.…”

mentioning

confidence: 97%

Rapid evolution of a bacterial parasite during outbreaks in two Daphnia populations

Shaw

Duffy

2023

Ecology and Evolution

Self Cite

View full text Add to dashboard Cite

Parasite genotypes vary in traits that impact their fitness, including infectivity, virulence, and the ability to persist in the environment (Refardt & Ebert, 2007;Rogalski & Duffy, 2020;Salvaudon et al., 2005) As epidemics progress, parasite population structure changes due to selection on these traits, which can influence epidemic dynamics. Understanding how parasite population structure and diversity change during epidemics is important for public health, conservation, and our fundamental understanding of parasitism. Despite this, aside from studies on some humans pathogens (e.g., ebolavirus (

show abstract

“…Though there is phenotypic evidence that P. ramosa evolution occurs over the course of outbreaks (Auld et al, 2014;Paplauskas et al, 2021;Gowler et al, 2022), we did not know how parasite genotype assemblages would change within outbreaks. Parasite genotypic diversity could increase as mutations occur, decrease if parasites adapt to low-diversity host populations, or be maintained if different genotypes are favored through time due to negative frequency dependent selection and/or by reintroduction from the spore bank.…”

Section: Introductionmentioning

confidence: 96%

Rapid evolution of a bacterial parasite during outbreaks in two Daphnia populations

Shaw

Duffy

2022

Preprint

Self Cite

View full text Add to dashboard Cite

Myriad ecological and evolutionary factors can influence whether a particular parasite successfully transmits to a new host during a disease outbreak, with consequences for the structure and diversity of parasite populations. However, even though the diversity and evolution of parasite populations is of clear fundamental and applied importance, we have surprisingly few studies that track how genetic structure of parasites changes during naturally occurring outbreaks in non-human populations. Here, we used population genetic approaches to reveal how genotypes of a bacterial parasite, Pasteuria ramosa, change over time, focusing on how infecting P. ramosa genotypes change during the course of epidemics in Daphnia populations in two lakes. We found evidence for genetic change – and, therefore, evolution – of the parasite during outbreaks. In one lake, P. ramosa genotypes structured by sampling date; in both lakes, genetic distance between groups of P. ramosa isolates increased with time between sampling. Diversity in parasite populations remained constant over epidemics, though one epidemic (which was large) had low genetic diversity while the other epidemic (which was small) had high genetic diversity. Our findings demonstrate that patterns of parasite evolution differ between outbreaks; future studies exploring the feedbacks between epidemic size, host diversity, and parasite genetic diversity would improve our understanding of parasite dynamics and evolution.

show abstract

Virulence evolution during a naturally occurring parasite outbreak

Cited by 7 publications

References 55 publications

Hatchability of Fascioloides magna Eggs in Cervids

Hatchability of Fascioloides magna Eggs in Cervids

Rapid evolution of a bacterial parasite during outbreaks in two Daphnia populations

Rapid evolution of a bacterial parasite during outbreaks in two Daphnia populations

Contact Info

Product

Resources

About