Researchers determined that Ebola virus infection was more widespread than originally thought in the village where experts believe the West African Ebola epidemic began, according to a study published in The Lancet Infectious Diseases.
After testing oral swabs and conducting detailed interviews, the researchers said they identified 10 more cases in Meliandou, Guinea, bringing the total number of cases in the village to 21.
The study produced the first serologic evidence that Ebola-infected survivors were living in Meliandou, according to Joseph W.S. Timothy, PhD, a research fellow at the London School of Hygiene & Tropical Medicine, and colleagues.
“This cross-sectional seroprevalence survey used detailed investigation and non-invasive immunological tools to document Ebola virus transmission at the index site of the largest recorded outbreak of human [Ebola virus disease]. Although an outbreak investigation was done in 2014, no diagnostic or immunological methods have been previously used in Meliandou,” Timothy and colleagues wrote.
From June 22 through July 9, 2017, the researchers enrolled 237 participants from 27 households who provided an oral fluid swab using Oracol Plus collection devices (Malvern Medical Developments). In interviews, participants were “prompted to describe the events of the outbreak, any illness within the household and possible contact with suspected cases,” Timothy and colleagues explained.
Results of antibody testing showed that in addition to the 11 deaths from the outbreak that were described previously, there were two probable Ebola deaths and eight previously unrecognized anti-Ebola virus IgG-positive survivors — including one who had mild symptoms and one who was asymptomatic — resulting in a case fatality rate of 55.6% (95%, CI, 30.8–78.5) for adults, and not 100% as had been previously reported, Timothy and colleagues reported.
Our conclusions highlight the importance and potential of deploying appropriate quantitative serological tools,” they wrote. “The acceptability and specificity of this approach alongside careful epidemiological investigation provide comprehensive understanding of transmission dynamics in Meliandou.
“These data thoroughly characterize the initiating events of an Ebola virus outbreak and show that it spread further within this community than previously appreciated. They also show that it is possible to access a large proportion of a deeply affected community by building up trust and using an acceptable and noninvasive approach.” – by Caitlyn Stulpin
Disclosures: The authors report no relevant financial disclosures.