The Ebola virus sweeping through West Africa has mutated repeatedly during the current outbreak, a fact that could hinder diagnosis and treatment of the devastating disease, according to scientists who have genetically sequenced the virus in scores of victims.
The findings, published Thursday in the journal Science, also offer new insights into the origins of the largest and most deadly Ebola outbreak in history, which has killed more than 1,500 people in four countries and shows few signs of slowing. It also provided another reminder of the deep toll the outbreak has taken on health workers and others in the affected areas, as five of the paper’s more than 50 co-authors died from Ebola before publication.
In a collaboration led by scientists at Harvard University and aided by officials at Sierra Leone’s health ministry, researchers sequenced Ebola virus genomes from 78 patients beginning in the early days of the outbreak this spring. Those 99 samples — some patients were tested more than once — suggested that the outbreak began with a single human infection before spreading rapidly, like a spark that grows into a wildfire.
Ebola’s arrival in Sierra Leone in May started with a funeral, according to Thursday’s findings. A young pregnant woman tested positive for the virus and was treated at Kenema Government Hospital. Health workers who traced her contacts discovered that she and more than a dozen other women recently had attended the burial of a traditional healer who had been treating Ebola patients near the Sierra Leone-Guinea border. All of them had been infected.