RAVIGNÉ Virginie's profile
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RAVIGNÉ Virginie

  • PVBMT, CIRAD, Saint-Pierre, Réunion, France
  • Adaptation, Bioinformatics & Computational Biology, Evolutionary Applications, Evolutionary Dynamics, Evolutionary Epidemiology, Evolutionary Theory, Experimental Evolution, Population Genetics / Genomics, Reproduction and Sex, Species interactions
  • recommender

Recommendation:  1

Review:  1

Educational and work
I am researcher at CIRAD in PVBMT research unit in Saint-Pierre (Réunion, France). I made my PhD in Isabelle Olivieri's group at ISEM, Montpellier (France). After a post-doc in Laurent Keller's group in Lausanne (Switzerland), I became lecturer at the University of Pau (France). Since 2007 I have been working at Cirad. I use theoretical biology and population genetics to understand the propagation and success of emergent plant pathogens and bioagressors. View my publications here https://vravigne.wordpress.com/publications/

Recommendation:  1

22 May 2017
article picture

Can Ebola Virus evolve to be less virulent in humans?

A new hypothesis to explain Ebola's high virulence

Recommended by and based on reviews by François Blanquart and Virginie Ravigné

 

The tragic 2014-2016 Ebola outbreak that resulted in more than 28,000 cases and 11,000 deaths in West Africa [1] has been a surprise to the scientific community. Before 2013, the Ebola virus (EBOV) was known to produce recurrent outbreaks in remote villages near tropical rainforests in Central Africa, never exceeding a few hundred cases with very high virulence. Both EBOV’s ability to circulate for several months in large urban human populations and its important mutation rate suggest that EBOV’s virulence could evolve and to some extent adapt to human hosts [2]. Up to now, the high virulence of EBOV in humans was generally thought to be maladaptive, the virus being adapted to circulating in wild animal populations (e.g. fruit bats [3]). As a logical consequence, EBOV virulence could be expected to decrease during long epidemics in humans. The present paper by Sofonea et al. [4] challenges this view and explores how, given EBOV’s life cycle and known epidemiological parameters, virulence is expected to evolve in the human host during long epidemics. The main finding of the paper is that there is no chance that EBOV’s virulence decreases in the short and long terms. The main underlying mechanism is that EBOV is also transmitted by dead bodies, which limits the cost of virulence. In itself the idea that selection should select for higher virulence in diseases that are also transmitted after host death will sound intuitive for most evolutionary epidemiologists. The accomplishment of the paper is to make a very strong case that the parameter range where virulence could decrease is very small. The paper further provides scientifically grounded arguments in favor of the safe management of corpses. Safe burial of corpses is culturally difficult to impose. The present paper shows that in addition to instantaneously decreasing the spread of the virus, safe burial may limit virulence increase in the short term and favor of less virulent strains in the long term. Altogether these results make a timely and important contribution to the knowledge and understanding of EBOV.

References

[1] World Health Organization. 2016. WHO: Ebola situation report - 10 June 2016.

[2] Kupferschmidt K. 2014. Imagining Ebola’s next move. Science 346: 151–152. doi: 10.1126/science.346.6206.151

[3] Leroy EM, Kumulungui B, Pourrut X, Rouquet P, Hassanin A, Yaba P, Délicat A, Paweska, Gonzalez JP and Swanepoel R. 2005. Fruit bats as reservoirs of Ebola virus. Nature 438: 575–576. doi: 10.1038/438575a

[4] Sofonea MT, Aldakak L, Boullosa LFVV and Alizon S. 2017. Can Ebola Virus evolve to be less virulent in humans? bioRxiv 108589, ver. 3 of 19th May 2017; doi: 10.1101/108589

Review:  1

22 May 2017
article picture

Can Ebola Virus evolve to be less virulent in humans?

A new hypothesis to explain Ebola's high virulence

Recommended by and based on reviews by François Blanquart and Virginie Ravigné

 

The tragic 2014-2016 Ebola outbreak that resulted in more than 28,000 cases and 11,000 deaths in West Africa [1] has been a surprise to the scientific community. Before 2013, the Ebola virus (EBOV) was known to produce recurrent outbreaks in remote villages near tropical rainforests in Central Africa, never exceeding a few hundred cases with very high virulence. Both EBOV’s ability to circulate for several months in large urban human populations and its important mutation rate suggest that EBOV’s virulence could evolve and to some extent adapt to human hosts [2]. Up to now, the high virulence of EBOV in humans was generally thought to be maladaptive, the virus being adapted to circulating in wild animal populations (e.g. fruit bats [3]). As a logical consequence, EBOV virulence could be expected to decrease during long epidemics in humans. The present paper by Sofonea et al. [4] challenges this view and explores how, given EBOV’s life cycle and known epidemiological parameters, virulence is expected to evolve in the human host during long epidemics. The main finding of the paper is that there is no chance that EBOV’s virulence decreases in the short and long terms. The main underlying mechanism is that EBOV is also transmitted by dead bodies, which limits the cost of virulence. In itself the idea that selection should select for higher virulence in diseases that are also transmitted after host death will sound intuitive for most evolutionary epidemiologists. The accomplishment of the paper is to make a very strong case that the parameter range where virulence could decrease is very small. The paper further provides scientifically grounded arguments in favor of the safe management of corpses. Safe burial of corpses is culturally difficult to impose. The present paper shows that in addition to instantaneously decreasing the spread of the virus, safe burial may limit virulence increase in the short term and favor of less virulent strains in the long term. Altogether these results make a timely and important contribution to the knowledge and understanding of EBOV.

References

[1] World Health Organization. 2016. WHO: Ebola situation report - 10 June 2016.

[2] Kupferschmidt K. 2014. Imagining Ebola’s next move. Science 346: 151–152. doi: 10.1126/science.346.6206.151

[3] Leroy EM, Kumulungui B, Pourrut X, Rouquet P, Hassanin A, Yaba P, Délicat A, Paweska, Gonzalez JP and Swanepoel R. 2005. Fruit bats as reservoirs of Ebola virus. Nature 438: 575–576. doi: 10.1038/438575a

[4] Sofonea MT, Aldakak L, Boullosa LFVV and Alizon S. 2017. Can Ebola Virus evolve to be less virulent in humans? bioRxiv 108589, ver. 3 of 19th May 2017; doi: 10.1101/108589

avatar

RAVIGNÉ Virginie

  • PVBMT, CIRAD, Saint-Pierre, Réunion, France
  • Adaptation, Bioinformatics & Computational Biology, Evolutionary Applications, Evolutionary Dynamics, Evolutionary Epidemiology, Evolutionary Theory, Experimental Evolution, Population Genetics / Genomics, Reproduction and Sex, Species interactions
  • recommender

Recommendation:  1

Review:  1

Educational and work
I am researcher at CIRAD in PVBMT research unit in Saint-Pierre (Réunion, France). I made my PhD in Isabelle Olivieri's group at ISEM, Montpellier (France). After a post-doc in Laurent Keller's group in Lausanne (Switzerland), I became lecturer at the University of Pau (France). Since 2007 I have been working at Cirad. I use theoretical biology and population genetics to understand the propagation and success of emergent plant pathogens and bioagressors. View my publications here https://vravigne.wordpress.com/publications/