Detection of Middle East Respiratory Syndrome Coronavirus-Specific RNA and Anti-MERS-Receptor-Binding Domain Antibodies in Camel Milk from Different Regions of Saudi Arabia

Middle East respiratory syndrome coronavirus (MERS-CoV) causes viral pneumonia disease in humans. The close contact with camels and drinking milk may cause MERS-CoV transfer to humans. This study was designed to detect the existence of MERS-CoV in camel milk samples collected from healthy animals of various barns located around Saudi Arabia. Camel milk samples were examined for MERS-CoV RNA by real time-quantitative polymerase chain reaction, also enzyme-linked immunosorbent assay was performed to detect IgG antibodies directed against Middle East respiratory syndrome receptor-binding domain. Among 83 camel milk samples tested, the result showed that seven samples (8.4%) were positive for MERS-CoV RNA, whereas 40.9% of camel milk samples had antibodies directed against MERS-CoV. The findings indicate that some regions (East and South part) are characterized by a high incidence of viral antibodies. The Southwestern region displayed the lowest infection rates. Among the camel breeds, the lowest positivity for detection of MERS-CoV RNA and IgG antibodies was found in Sahilia. This could be related to a higher resistance to viral infection of the breed Sahilia and/or to the geographical origin of the camels sampled in the study. This needs to be more explored to reduce spread of infection and also to understand the underlying reasons. The presence of viral RNA in camel milk samples warrants for measures to prevent possible foodborne transmission of MERS-CoV through milk consumption.