MERS-coronavirus: From discovery to intervention

Widagdo, W.; Okba, Nisreen M.A.; Stalin Raj, V.; Haagmans, Bart L.

Efforts to screen other animal species for MERS-CoV are currently ongoing. Phylogenetic analysis using RBD within DPP4 of different species identified several livestock animals, i.e. sheep, goats, cattle, llamas and horses to cluster together with other susceptible animals, including dromedary camels. Transfection of non-susceptible cells with DPP4 of these different animal species converted these cells to become susceptible to MERS-CoV [79, 80] . However, serological studies did not provide evidence for MERS-CoV circulating in these animals [13, 66, 81] . Experimental MERS-CoV infections showed that alpacas shed infectious virus up to twelve days post inoculation [82] , and they could transmit infectious virus to other naïve alpacas [83] . These observations are consistent with findings from a study at a farm located in the Al Shahaniya region of Qatar which showed that 15 out of 20 alpacas were found positive for neutralizing antibodies against MERS-CoV. These alpacas were housed nearby to camels, also seropositive for MERS-CoV, and taken care of by the same shepherds [84] . Although pigs and llamas were found susceptible to MERS-CoV upon experimental infection [85] , thus far no evidence was obtained from the field for seroconversion in these animal species. Limited shedding of infectious virus was reported in goat, sheep, and horse experimentally inoculated with MERS-CoV, suggesting that these animals play minimal to no role in spreading MERS-CoV in current outbreaks [86] . These studies suggest that among the livestock animals, dromedary camels are the main species responsible for spreading the virus.