MERS Study Reveals Genetic Bouquet…(Prepare Yourselves…)
20 September 2013
Triple threat. A genetic study reveals that more than one lineage of the deadly MERS virus is circulating in the Middle East.
The precise origin of the virus that causes the deadly Middle East respiratory syndrome (MERS) remains obscure. But the largest genetic analysis to date reveals that several varieties of the MERS virus are circulating in Saudi Arabia, leading some to believe the virus reached humans from multiple sources.
Since the first documented cases in 2012, MERS has killed 58 people and sickened 132, most of them in Saudi Arabia, according to the U.S. Centers for Disease Control and Prevention. Scientists know the virus has a limited ability to spread from person to person, but they aren’t sure about the path it took to reach its first human victims. Last month, a small fragment of the virus’s genome turned up in a Saudi Arabian bat, and retired racing camels in Oman were found to carry antibodies against the virus. However, a direct link between these possible animal hosts, known as reservoirs, and the first people who contracted MERS hasn’t been found.
To explore the genetic diversity of MERS, virologist Paul Kellam of the Wellcome Trust Sanger Institute in Hinxton, United Kingdom, and an international team of colleagues sequenced viral genomes sampled from 21 patients in Saudi Arabia between June 2012 and June 2013. Many came from an outbreak of the virus at a hospital in the eastern city of Al-Hasa this spring. The group hoped to capitalize on the differences that emerge as a virus evolves to work backwards to the earliest MERS ancestors. Using these differences, the group constructed a tree of the 21 cases to predict how long ago the virus may have appeared in humans, how much it has changed since then, and how it has spread geographically.