Most of the people who were infected with Ebola in the 2014 West Africa epidemic contracted the viral disease through “super-spreaders”, researchers say.
According to a study published on Monday in the Proceedings of the National Academy of Sciences, scientists said super-spreaders, a small percentage of people who are responsible for infecting several others during epidemics of infectious diseases, played a central role in the spread of Ebola.
Researchers said 61 percent of those afflicted were infected by just three percent of others those who got sick, the researchers said.
If super-spreading had been completely under control, about two-thirds of Ebola cases could have been avoided, the report said.
“We now see the role of super-spreaders as larger than initially suspected,” said Benjamin Dalziel, a co-author of the study.
“It was the cases you didn’t see that really drove the epidemic, particularly people who died at home, without making it to a care centre.”
At the time, researchers counted cases according to those seen in medical centres, but they later realised these were a small fraction of the total.
“There wasn’t a lot of transmission once people reached hospitals and care centre,” said Dalziel.
“In our analysis, we were able to see a web of transmission that would often track back to a community-based super-spreader.”
In early 2014, a handful of infections in southern Guinea mushroomed rapidly into an epidemic.
Over the next two years, more than 28,000 people fell ill, mainly in Guinea, Liberia and Sierra Leone. With a mortality rate above 40 percent, some 11,300 died.
Super-spreaders have also played a role in the epidemic of severe acute respiratory syndrome, or SARS, in 2003 and Middle East respiratory syndrome in 2012.