Concerns about Misinterpretation of Recent Scientific Data Implicating Dromedary Camels in Epidemiology of Middle East Respiratory Syndrome (MERS)

Samara, Emad M.; Abdoun, Khalid A.

Aiming to investigate the possible role of DCs in the transmission of MERS-CoV to humans, the authors in their first article determined the seroprevalence of MERS-CoV infection in DCs throughout Saudi Arabia and arrived at three main conclusions (1) . Their first conclusion was that DCs can be infected with MERS-CoV, as evident by the determination of (i) high loads of viral nucleic acids (RNA) and antibodies to MERS-CoV in archived and freshly collected samples and (ii) a high resemblance (Ͼ99%) in the collected samples in three regions of phylogenetically analyzed MERS-CoV genomic sequence. Their second conclusion is that there are seroprevalence differences in MERS-CoV infection depending on the camel's age (95% of the adults compared to 35% of the juveniles) and the region of the country (ranging from 90% in the East to 5% in the Southwest). The third conclusion is that airborne transmission is the main mode of MERS-CoV transmission, as evidenced by the more frequent detection of viral nucleic acids in nasal swabs than in rectal specimens. Furthermore, the authors in their second article described complete genomic sequencing of MERS-CoV isolated from both DCs and humans and arrived at two more conclusions (2) . First, they demonstrated that DCs can be simultaneously infected with three genetic variants (genotypes) of MERS-CoV; second, they showed that the alignment of the complete genomic sequence of one MERS-CoV genotype (claimed to be a quasispecies) obtained from culturing the virus from nasal swab samples of DCs was indistinguishable from the genomic sequence of MERS-CoV recovered from humans. Based on all these findings, the authors speculated that DCs may have a role or serve as a potential reservoir or vector of MERS-CoV in human infection and they clearly argued that we ought to orient future investigations on MERS disease among humans toward direct or indirect exposure to DCs.