Evolution of Virulence in Emerging Epidemics

Berngruber, Thomas W.; Froissart, Rémy; Choisy, Marc; Gandon, Sylvain

doi:10.1371/journal.ppat.1003209

Cited by 163 publications

(258 citation statements)

References 43 publications

Supporting

Mentioning

238

Contrasting

Order By: Relevance

“…Evolutionary theory predicts that at higher pathogen prevalence, less virulent pathogen strains will be more common, and this has been supported empirically (Berngruber et al 2013). In systems where the supply of susceptible host plants is regularly renewed, however, more virulent pathogens may continue to prevail (Smart and Fry 2001).…”

Section: Discussionmentioning

confidence: 97%

Interactions Within Susceptible Hosts Drive Establishment of Genetically Distinct Variants of an Insect-Borne Pathogen

et al. 2015

View full text Add to dashboard Cite

Coinfections are common, leading to pathogen interactions during transmission and establishment in a host. However, few studies have tested the relative strengths of pathogen interactions in vectors and hosts that determine the outcome of infection. We tested interactions between two genetically distinct variants of the mealybug-transmitted Grapevine leafroll-associated virus 3. The transmission efficiency of each variant in single variant inoculations by two vector species was determined. The effects of vector species, a coinfected source, and simultaneous inoculation from multiple hosts to one host on variant establishment were examined. Within-vector interactions could have a role in transmission from hosts containing mixed infections, but not when vectors were moved from separate singly infected source plants to a single recipient plant. The invasive Planococcus ficus (Signoret) was a more efficient vector than Pseudococcus viburni (Signoret). Transmission efficiency of the two variants did not differ in single variant inoculations. Overall infections were the same whether from singly or coinfected source plants. In mixed inoculations, establishment of one variant was reduced. Mixed inoculations from two singly infected source plants resulted in fewer mixed infections than expected by chance. Therefore, the observed outcome was determined subsequent to host inoculation rather than in the vector. The outcome may be due to resource competition between pathogens. Alternatively apparent competition may be responsible; the pathogens' differential ability to overcome host defenses and colonize the host may determine the final outcome of new infections. Detailed knowledge of interactions between pathogens during transmission and establishment could improve understanding and management of disease spread.

show abstract

Section: Discussionmentioning

confidence: 97%

Interactions Within Susceptible Hosts Drive Establishment of Genetically Distinct Variants of an Insect-Borne Pathogen

et al. 2015

View full text Add to dashboard Cite

show abstract

“…Indeed, changes in virulence have been associated with the effects of parasites on host population dynamics [1], [5], the reduction of ecosystem biodiversity [6], [7], and the emergence and re-emergence of infectious diseases [8],[9]. In the last three decades considerable effort has been devoted to developing theoretical models that predict conditions favouring the increase or decrease of parasite virulence.…”

Section: Introductionmentioning

confidence: 99%

Vertical Transmission Selects for Reduced Virulence in a Plant Virus and for Increased Resistance in the Host

et al. 2014

View full text Add to dashboard Cite

For the last three decades, evolutionary biologists have sought to understand which factors modulate the evolution of parasite virulence. Although theory has identified several of these modulators, their effect has seldom been analysed experimentally. We investigated the role of two such major factors—the mode of transmission, and host adaptation in response to parasite evolution—in the evolution of virulence of the plant virus Cucumber mosaic virus (CMV) in its natural host Arabidopsis thaliana. To do so, we serially passaged three CMV strains under strict vertical and strict horizontal transmission, alternating both modes of transmission. We quantified seed (vertical) transmission rate, virus accumulation, effect on plant growth and virulence of evolved and non-evolved viruses in the original plants and in plants derived after five passages of vertical transmission. Our results indicated that vertical passaging led to adaptation of the virus to greater vertical transmission, which was associated with reductions of virus accumulation and virulence. On the other hand, horizontal serial passages did not significantly modify virus accumulation and virulence. The observed increases in CMV seed transmission, and reductions in virus accumulation and virulence in vertically passaged viruses were due also to reciprocal host adaptation during vertical passages, which additionally reduced virulence and multiplication of vertically passaged viruses. This result is consistent with plant-virus co-evolution. Host adaptation to vertically passaged viruses was traded-off against reduced resistance to the non-evolved viruses. Thus, we provide evidence of the key role that the interplay between mode of transmission and host-parasite co-evolution has in determining the evolution of virulence.

show abstract

“…Among biological traits assumed to be under strong evolutionary pressure, the virulence of pathogens, generally defined as the quantitative ability of a pathogen to induce host mortality [11,12], is the focus of considerable attention from evolutionary ecologists [12] and plant pathologists [13]. Despite still imprecise experimental characterizations, mainly based on proxies, and a complex theory including the transmission-virulence trade-off hypothesis [14], the evolution at this trait is thought to be tightly related to the spread of diseases [11,15,16].…”

Section: Introductionmentioning

confidence: 99%

“…Despite still imprecise experimental characterizations, mainly based on proxies, and a complex theory including the transmission-virulence trade-off hypothesis [14], the evolution at this trait is thought to be tightly related to the spread of diseases [11,15,16]. This evolutionary perspective, together with the large spatio-temporal scales considered in forestry and the often numerous uncertainties about the biology of the pathogens, make integrative experimental assessments of the effects of common forestry practices on fungal pathogen populations hardly feasible.…”

Section: Introductionmentioning

confidence: 99%

“…Interestingly, a theoretical framework focused on the integration of the co-occurring epidemiological and evolutionary processes at short time-scales has been set (e.g., [17][18][19]). For instance, assuming a population made of a wild and a mutant genotype showing distinct virulence and transmission rates, Berngrüber set a mathematical model to explore the transient effects of mutation on virulence evolution in a bacteriophage virus during the onset of epidemics [11]. On the same basis and for the same kind of organism, Griette et al showed that the level of virulence determines the speed of epidemics but also that virulence is favored at the front line of an epidemic and counter-selected behind the front [16].…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Short Rotations in Forest Plantations Accelerate Virulence Evolution in Root-Rot Pathogenic Fungi

Soularue

Robin

Desprez‐Loustau

et al. 2017

Forests

View full text Add to dashboard Cite

As disease outbreaks in forest plantations are causing concern worldwide, a clear understanding of the influence of silvicultural practices on the development of epidemics is still lacking. Importantly, silvicultural practices are likely to simultaneously affect epidemiological and evolutionary dynamics of pathogen populations. We propose a genetically explicit and individual-based model of virulence evolution in a root-rot pathogenic fungus spreading across forest landscapes, taking the Armillaria ostoyae-Pinus pinaster pathosystem as reference. We used the model to study the effects of rotation length on the evolution of virulence and the propagation of the fungus within a forest landscape composed of even-aged stands regularly altered by clear-cutting and thinning operations. The life cycle of the fungus modeled combines asexual and sexual reproduction modes, and also includes parasitic and saprotrophic phases. Moreover, the tree susceptibility to the pathogen is primarily determined by the age of the stand. Our simulations indicated that the shortest rotation length accelerated both the evolution of virulence and the development of the epidemics, whatever the genetic variability in the initial fungal population and the asexuality rate of the fungal species.

show abstract

Evolution of Virulence in Emerging Epidemics

Cited by 163 publications

References 43 publications

Interactions Within Susceptible Hosts Drive Establishment of Genetically Distinct Variants of an Insect-Borne Pathogen

Interactions Within Susceptible Hosts Drive Establishment of Genetically Distinct Variants of an Insect-Borne Pathogen

Vertical Transmission Selects for Reduced Virulence in a Plant Virus and for Increased Resistance in the Host

Short Rotations in Forest Plantations Accelerate Virulence Evolution in Root-Rot Pathogenic Fungi

Contact Info

Product

Resources

About