Molecular Evolution of MERS Coronavirus: Dromedaries as a Recent Intermediate Host or Long-Time Animal Reservoir?

Lau, Susanna K. P.; Wong, Antonio C. P.; Lau, Terrence C. K.; Woo, Patrick C. Y.

Since its first appearance in 2012, the Middle East Respiratory Syndrome (MERS) has affected more than 25 countries in four continents with more than 1900 cases and a frightening fatality rate of more than 30% [1] . A novel lineage C betacoronavirus, MERS coronavirus (MERS-CoV), has been confirmed to be the etiological agent of MERS [2, 3] . Subsequent detection of MERS-CoV and its antibodies in dromedaries in various countries in the Middle East and North Africa have implied that these animals are probably the reservoir for MERS-CoV [4] [5] [6] . In addition, the discovery of other closely related lineage C betacoronaviruses both before and after the MERS epidemic in various bat species and hedgehogs [7] [8] [9] [10] , as well as the demonstration of the ability of the spike protein of Tylonecteris bat CoV HKU4 to bind dipeptidyl peptidase 4 [11, 12] , the receptor of MERS-CoV, have also suggested that these animals could be the hosts for the ancestor of MERS-CoV. However, it is still uncertain how and when the ancestor of MERS-CoV may have jumped from bats/hedgehogs to camels and humans.