The Ebola virus has mutated 300 times since the outbreak began in West Africa in May, and these transformations lead scientists to conclude that it is unlike any past Ebola epidemic. This could make it both harder to treat and harder to diagnose, according to a study published in Science magazine. The outbreak began as a single human infection, the authors write, but the genetic sequences observed in the 78 patients sampled showed a rapid spread in both the number of people infected and the geographical regions affected.
The initial infection came from one of five strains of Ebola known to affect humans called the Zaire strain. The Zaire strain emerged about a decade ago in a related strain from an animal host. Researchers are not positive which animal hosted the virus, but believe that it most likely was a bat in Guinea. At least one species of fruit bat has a geographic range that spreads from Guinea to Sierra Leone. If bats are really the culprit, “about 150 million more people than previously thought are at risk of the disease,” according to a previous study published in Science.
Clues from the study have scientists hopeful that nonstop research on mutations will help develop new diagnostic tests and treatments. In the study, 99 Ebola samples were taken from 78 patients diagnosed with Ebola from May to late June. More than 50 people co-authored the study with help from Harvard University scientists and the Sierra Leone Health Ministry. Five of the authors died before the paper was even published. Read the study abstract.
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