title: Ebola viral load at diagnosis associates with patient outcome and outbreak evolution.
abstract: BACKGROUND
  Ebola virus (EBOV) causes periodic outbreaks of life-threatening EBOV disease in Africa. Historically, these outbreaks have been relatively small and geographically contained; however, the magnitude of the EBOV outbreak that began in 2014 in West Africa has been unprecedented. The aim of this study was to describe the viral kinetics of EBOV during this outbreak and identify factors that contribute to outbreak progression.
  
  
  METHODS
  From July to December 2014, one laboratory in Sierra Leone processed over 2,700 patient samples for EBOV detection by quantitative PCR (qPCR). Viremia was measured following patient admission. Age, sex, and approximate time of symptom onset were also recorded for each patient. The data was analyzed using various mathematical models to find trends of potential interest.
  
  
  RESULTS
  The analysis revealed a significant difference (P = 2.7 × 10(-77)) between the initial viremia of survivors (4.02 log10 genome equivalents [GEQ]/ml) and nonsurvivors (6.18 log10 GEQ/ml). At the population level, patient viral loads were higher on average in July than in November, even when accounting for outcome and time since onset of symptoms. This decrease in viral loads temporally correlated with an increase in circulating EBOV-specific IgG antibodies among individuals who were suspected of being infected but shown to be negative for the virus by PCR.
  
  
  CONCLUSIONS
  Our results indicate that initial viremia is associated with outcome of the individual and outbreak duration; therefore, care must be taken in planning clinical trials and interventions. Additional research in virus adaptation and the impacts of host factors on EBOV transmission and pathogenesis is needed.
authors.forename: Marc-Antoine
authors.initials: MA
authors.lastname: de La Vega
authors.forename: Grazia
authors.initials: G
authors.lastname: Caleo
authors.forename: Jonathan
authors.initials: J
authors.lastname: Audet
authors.forename: Xiangguo
authors.initials: X
authors.lastname: Qiu
authors.forename: Robert A
authors.initials: RA
authors.lastname: Kozak
authors.forename: James I
authors.initials: JI
authors.lastname: Brooks
authors.forename: Steven
authors.initials: S
authors.lastname: Kern
authors.forename: Anja
authors.initials: A
authors.lastname: Wolz
authors.forename: Armand
authors.initials: A
authors.lastname: Sprecher
authors.forename: Jane
authors.initials: J
authors.lastname: Greig
authors.forename: Kamalini
authors.initials: K
authors.lastname: Lokuge
authors.forename: David K
authors.initials: DK
authors.lastname: Kargbo
authors.forename: Brima
authors.initials: B
authors.lastname: Kargbo
authors.forename: Antonino
authors.initials: A
authors.lastname: Di Caro
authors.forename: Allen
authors.initials: A
authors.lastname: Grolla
authors.forename: Darwyn
authors.initials: D
authors.lastname: Kobasa
authors.forename: James E
authors.initials: JE
authors.lastname: Strong
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Ippolito
authors.forename: Michel
authors.initials: M
authors.lastname: Van Herp
authors.forename: Gary P
authors.initials: GP
authors.lastname: Kobinger
mesh_terms: D000914:Antibodies, Viral / Q000097:blood; D004196:Disease Outbreaks; D029043:Ebolavirus; D005260:Female; D019142:Hemorrhagic Fever, Ebola / Q000097:blood* / Q000401:mortality*; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood; D008297:Male; D008954:Models, Biological; D012807:Sierra Leone; D019562:Viral Load
chemical_list: D000914:Antibodies, Viral; D007074:Immunoglobulin G