Background: Detailed information on patient exposure, contact patterns, and discharge status is rarely available in real time from traditional surveillance systems in the context of an emerging infectious disease outbreak. Here, we validate the systematic collection of Internet news reports to characterize epidemiological patterns of Ebola virus disease (EVD) infections during the West African 2014-2015 outbreak.
Methods: Based on 58 news reports, we analyzed 79 EVD clusters (286 cases) ranging in size from 1 to 33 cases between January 2014 and February 2015 in Guinea, Sierra Leone, and Liberia.
Results: The majority of reported exposures stemmed from contact with family members (57.3%) followed by hospitals (18.2%) and funerals (12.7%). Our data indicate that funeral exposure was significantly more frequent in Sierra Leone (27.3%) followed by Guinea (18.2%) and Liberia (1.8%; χ(2) test; P < .0001). Funeral exposure was the dominant route of transmission until April 2014 (60%) and was replaced with hospital exposure in June 2014-July 2014 (70%), both of which declined after interventions were put in place. The mean reproduction number of the outbreak was 2.3 (95% confidence interval [CI], 1.8, 2.7). The case fatality rate was estimated at 74.4% (95% CI, 68.3, 79.8).
Conclusions: Overall, our findings based on news reports are in close agreement with those derived from traditional epidemiological surveillance data and with those reported for prior outbreaks. Our findings support the use of real-time information from trustworthy news reports to provide timely estimates of key epidemiological parameters that may be hard to ascertain otherwise.
Keywords: Ebola; West Africa; funeral transmission; hospital transmission; transmission patterns.
Published by Oxford University Press for the Infectious Diseases Society of America 2015. This work is written by (a) US Government employee(s) and is in the public domain in the US.