Absence of MERS-CoV antibodies in feral camels in Australia: Implications for the pathogen's origin and spread

Crameri, Gary; Durr, Peter A.; Barr, Jennifer; Yu, Meng; Graham, Kerryne; Williams, Owen J.; Kayali, Ghazi; Smith, David; Peiris, Malik; Mackenzie, John S.; Wang, Lin-Fa

At a first glance, it might seem that assessing the sero-status of feral camels, and the presence of CoVs in bats with potential contact with these camels has little relevance to understanding the epidemiology and evolution of MERS-CoV in the Arabian Peninsula. However, such are the complexities of the virus and the disease that many key discoveries have been made by examining animals at the margin of the problem areas. The initial discovery that camels might be the principal reservoir of MERS-CoV arose following exploratory testing of camel serum collected from the Canary Islands, which then led onto a more systematic survey of camels from the Arabian Peninsula [38] . Similarly, the discovery of a plausible ancestor virus to MERS-CoV arose from the sampling of a bat species in South Africa, even though the species does not occur within the Arabian Peninsula [16, 39] . The important lesson from these examples is that when dealing with an emerging infectious disease with a complex epidemiology, conventional outbreak investigations may not resolve key questions, and thus there is a need for studies which might appear tangential. Some of these, as in the examples cited, might result in important discoveries, but it needs to be accepted that most will not. However, we argue that within the context of "proactive surveillance", then negative survey results can be immensely important in directing attention to where effort is needed, which in our example, is our recommendation for a follow-on sero-survey of camels in western Asia.