MERS coronavirus in camels

Abstract

MERS is a pneumonic illness caused by a novel coronavirus. From September 2012 to the 20th January 2014, there have been 178 confirmed human cases leading to 76 deaths. All the primary human cases were originated from countries within the Arabian peninsula. The human virus is believed to be of zoonotic origin, but its natural reservoir remains an enigma. Nasal swabs from apparently healthy dromedary camels (n=110; age >6 years) were collected in 2 abattoirs in Egypt between June and December of 2013. Samples were tested by real-time reverse transcriptase polymerase chain reactions (RT-PCRs) for MERS coronavirus. Four out of 110 swab samples from dromedaries were found to contain MERS coronaviruses sequences and one of these positive samples was selected for full genome characterization. The deduced genomic sequence of camel MERS coronavirus was 99% similar to those found in human cases. Serological studies also indicated that 48 out of 52 camel serum samples collected at the same geographical region were positive for MERS coronavirus, confirming that that there is a high prevalence of MERS coronavirus in dromedary camels. By contrast, sera from 179 persons working in dromedary abattoirs in Egypt were serologically negative for MERS-CoV, suggesting that transmission of this virus to humans is an uncommon event. However, as the study proves that dromedary camels are carrying the MERS-CoV, there is still a significant risk for humans to acquire this virus from this species. The current findings, together with previous work from us and those from others, suggest that dromedary camels can be a potential source of human MERS coronavirus infections. The detection of camel MERS coronavirus in Egypt further indicates that this virus circulates in animals beyond the Arabian peninsula. Overall, the results urge for 1) better surveillance of this virus in animals, in particular to camels, and 2) screening of patients with unexplained severe pneumonia for possible MERS coronavirus infection in Egypt, Eastern Africa, and beyond.