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Data Mining in the Influenza Research Database (IRD) and the Virus Pathogen Resource (ViPR) JCVI-GSCID/NIAID Workshop University of Limpopo 01 June 2011 Richard H. Scheuermann, Ph.D. Department of Pathology U.T. Southwestern Medical Center
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www.fludb.org
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www.viprbrc.org
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IDENTIFICATION OF ADAPTIVE DRIVERS OF SPECIES JUMP EVENTS
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Public Health Impact of Influenza Seasonal flu epidemics occur yearly during the fall/ winter months and result in 3-5 million cases of severe illness worldwide. More than 200,000 people are hospitalized each year with seasonal flu-related complications in the U.S. Approximately 36,000 deaths occur due to seasonal flu each year in the U.S. Populations at highest risk are children under age 2, adults age 65 and older, and groups with other comorbidities. Source: World Health Organization - http://www.who.int/mediacentre/factsheets/fs211/en/index.html
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Flu pandemics of the 20 th and 21 st centuries initiated by species jump events 1918 flu pandemic (Spanish flu) – subtype H1N1 (avian origin) – estimated to have claimed between 2.5% to 5.0% of the world’s population (20 > 100 million deaths) Asian flu (1957 – 1958) – subtype H2N2 (avian origin) – 1 - 1.5 million deaths Hong Kong flu (1968 – 1969) – subtype H3N2 (avian origin) – between 750,000 and 1 million deaths 2009 H1N1 – subtype H1N1 (swine origin) – ~ 16,000 deaths as of March 2010
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2009 Pandemic species jump
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Pandemic stages Adaptive drivers
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Basic reproductive number (R 0 ) Total number of secondary cases per case Reasonable surrogate of fitness Characteristics of pandemic viruses: – R 0 H >1, and – In genetic neighborhood of viruses with R 0 R>1 and R 0 H<1 Adaptive drivers Pandemic Viruses (R 0 H >1) Pandemic Viruses (R 0 H >1) Stuttering viruses (R 0 R>1 and R 0 H<1) Stuttering viruses (R 0 R>1 and R 0 H<1) Reservoir virus (R 0 R>1 and R 0 H<<1) Reservoir virus (R 0 R>1 and R 0 H<<1) A1A2
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Fitness barriers Constant barriers to fitness – host-specific biochemical pathways/components and innate immunity Dynamic barriers to fitness – adaptive immunity and health status Variable barriers to fitness – host genetic polymorphisms Include transmission barriers and replication barriers
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Fit pandemic virus Fit as a transmission source in reservoir species Fit in the transmission process from reservoir species to human Fit in human receipt of transmission Fit in infection establishment in human Fit in viral replication in human Fit for human to human transmission as above
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Is adaptive immunity relevant? In previous pandemics, new virus was largely novel to the adaptive immune system, especially antibody- mediated immunity Therefore, in contrast to seasonal antigenic drift, pandemic-related adaptive mutations do not need to target immune epitopes
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Adaptive drivers Pepin KM et al. (2010) “Identifying genetics markers of adaptation for surveillance of viral host jump” Nature Reviews Microbiology 8: 802-814.
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Stuttering transmission and adaptive drivers Stuttering transmission can reveal adaptive drivers by evidence of convergent evolution – Odds of finding the same neutral mutation by chance in multiple species jumps is low – Therefore, finding same mutation in multiple independent species jump events is strong evidence for adaptive driver
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Genetic convergence during species jump Virus isolate groups from IRD – Avian H5N1 (PB2) from Southeast Asia* up to 2003 (260 records) – reservoirs of source viruses – Human H5N1 (PB2) from Southeast Asia 2003-present (165 records) – many examples of independent species jumps Align amino acid sequence and calculate conservation score Identify highly conserved positions in avian records (≤1/260 variants) (557positions/759) – functionally restricted in reservoir Select subset in which two or more human isolates contained the same sequence variant – either due to human-human transmission or convergent evolution *China, Hong Kong, Indonesia, Thailand, Viet Nam
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Strain Search – PB2 avian H5N1 Southeast Asia up to 2003
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260 PB2 records
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Sequence variation analysis
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Position order
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Order by conservation score
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My Workbench
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Select strains with specific sequence alterations
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Convergent evolution candidates d d d
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Surface exposed PB2_A/MEXICO/INDRE4487/2009(H1N1) Conservation score All convergent evolution candidates 586, 591, 627, 629
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Convergent evolution candidates
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E627K
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E627K and species jump
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K660R
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Summary Human influenza pandemics are initiated by species jump events followed by sustained human to human transmission (R 0 H>1) Multiple independent occurrences of the same mutation during stuttering transmission is evidence of convergent evolution of adaptive drivers – hypotheses for experimental testing Surveillance for adaptive drivers in reservoir species could help anticipate the next pandemic N01AI40041
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43 Acknowledgments U.T. Southwestern – Richard Scheuermann – Burke Squires – Jyothi Noronha – Victoria Hunt – Shubhada Godbole – Brett Pickett – Ayman Al-Rawashdeh MSSM – Adolfo Garcia-Sastre – Eric Bortz – Gina Conenello – Peter Palese Vecna – Chris Larsen – Al Ramsey LANL – Catherine Macken – Mira Dimitrijevic U.C. Davis – Nicole Baumgarth Northrop Grumman – Ed Klem – Mike Atassi – Kevin Biersack – Jon Dietrich – Wenjie Hua – Wei Jen – Sanjeev Kumar – Xiaomei Li – Zaigang Liu – Jason Lucas – Michelle Lu – Bruce Quesenberry – Barbara Rotchford – Hongbo Su – Bryan Walters – Jianjun Wang – Sam Zaremba – Liwei Zhou IRD SWG – Gillian Air, OMRF – Carol Cardona, Univ. Minnesota – Adolfo Garcia-Sastre, Mt Sinai – Elodie Ghedin, Univ. Pittsburgh – Martha Nelson, Fogarty – Daniel Perez, Univ. Maryland – Gavin Smith, Duke Singapore – David Spiro, JCVI – Dave Stallknecht, Univ. Georgia – David Topham, Rochester – Richard Webby, St Jude USDA – David Suarez Sage Analytica – Robert Taylor – Lone Simonsen CEIRS Centers
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