In the fall of 2013, a little more than a year after the MERS coronvirus was first isolated in a Saudi patient, a study in the Lancet: Camels Found With Antibodies To MERS-CoV-Like Virus pointed to camels as being a likely zoonotic source of the virus.
Within months additional studies (see Eurosurveillance: Seroprevalence Of MERS-like Antibodies In Middle Eastern Camels) backed up this theory - and while the hunt for other potential reservoirs (including alpacas) continued - researchers began testing camels all over the world to see if the virus was more widespread, or was localized on the Arabian peninsula.
While camel testing in both Northern Asia and Australia turned up a blank, by the summer of 2014 we were seeing significant evidence that MERS (or a very MERS-like virus) had been circulating in East African camels for two decades (see EID Journal: MERS Antibodies In Camels – Kenya 1992-2013).
A few months later (in EID Journal: Three Decades Of MERS-CoV Antibodies In Camels), that timeline was pushed back even farther when 81.0% of samples from the camel-exporting countries of Sudan and Somalia tested positive going back 30 years.
This has led to some to surmise that the MERS virus arrived in the Middle East via their importation of camels from East Africa, and that is is a relatively recent arrival.
Today the EID Journal reports the first serological evidence that MERS-CoV has circulated among camels in South Asia. I've only posted some excerpts, so follow the link to read the full report.
Serologic Evidence for MERS-CoV Infection in Dromedary Camels, Punjab, Pakistan, 2012–2015
Muhammad Saqib1, Andrea Sieberg1, Muhammad Hammad Hussain, Muhammad Khalid Mansoor, Ali Zohaib, Erik Lattwein, Marcel Alexander Müller, Christian DrostenComments to Author , and Victor Max Corman
Dromedary camels from Africa and Arabia are an established source for zoonotic Middle East respiratory syndrome coronavirus (MERS-CoV) infection among humans. In Pakistan, we found specific neutralizing antibodies in samples from 39.5% of 565 dromedaries, documenting significant expansion of the enzootic range of MERS-CoV to Asia.
In this study, we examined dromedaries from Pakistan for exposure to MERS-CoV. We tested 565 serum samples, which we collected from 348 female and 217 male animals by using a convenience sampling strategy in 9 districts of Punjab, eastern Pakistan, during 2012–2015. The median age of the animals was 5 years.
Based on MERS-CoV antibodies in dromedary camels, our data suggest a risk for human exposure in Punjab, Pakistan, that is similar to risks in Africa and the Arabian Peninsula. Of note, Punjab shares a border with the state of Rajasthan in India, which harbors that country’s largest dromedary population. A similar risk for human exposure is likely for this part of India. However, findings of antibodies against MERS-CoV in migrant workers from these areas should be interpreted with caution because these workers often employed in Arabian countries. For Pakistan, our data largely exclude the scenario of a widely susceptible animal reservoir population in which de novo introduction of MERS-CoV could start an epizootic that could lead to spillover epidemics among humans.
Dr. Saqib is an assistant professor in the field of veterinary medicine, Faculty of Veterinary Science, University of Agriculture, Faisalabad. His main research interests are zoonotic and infectious diseases of domestic and zoo animals.