There’s something surprising that helps determine how damaging a disease is: distance.
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To learn more, start your googling with these keywords:
Direct transmission: occurs when a pathogen is transmitted to a new host by physical or close contact
Virulence: the degree of damage a pathogen causes its host
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Credits (and Twitter handles):
Script Writer: Kate Yoshida (@KateYoshida)
Script Editor: Alex Reich (@alexhreich)
Video Illustrator: Ever Salazar (@eversalazar)
Video Director: Kate Yoshida (@KateYoshida) and Alex Reich (@alexhreich)
Video Narrator: Kate Yoshida (@KateYoshida)
With Contributions From: Henry Reich, Emily Elert, Peter Reich, David Goldenberg
Music by: Nathaniel Schroeder: http://www.soundcloud.com/drschroeder
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References:
Blanquart, F., et al. (2016). A transmission-virulence evolutionary trade-off explains attenuation of HIV-1 in Uganda. Elife 5: 5.
de Roode, J.C., Yates, A.J., & Altizer, S. (2008). Virulence-transmission trade-offs and population divergence in virulence in a naturally occurring butterfly parasite. Proceedings of the National Academy of Science 105: 7489-7494
Ewald, P.W. (1983). Host-parasite relations, vectors, and the evolution of disease severity. Annual Reviews Ecology & Systematics 14: 465-485
Ewald, P.W. (1991). Waterborne transmission and the evolution of virulence among gastrointestinal bacteria. Epidemiology & Infection 106: 83-119.
Ewald, P.W. (1991). Transmission modes and the evolution of virulence: with special reference to cholera, influenza, and AIDS. Human Nature 2: 1-30.
Galvani, A.P. (2003) Epidemiology meets evolutionary ecology. Trends in Ecology & Evolution 18: 132-139.
Lipsitch, M. & Moxon, E.R. (1997). Virulence and transmissibility of pathogens: what is the relationship? Trends in Microbiology 5: 31-37.