Tuesday, August 23, 2016

Study: Experimental Infection Of Goats, Sheep & Horses With MERS-CoV



Almost two years ago in EID Journal: Replication & Shedding Of MERS-CoV In Inoculated Camels we looked at research from the MERS vaccine project at Colorado State University that documented that camels shed `copious' amounts of the MERS virus via nasal discharge while infected.

More recently, in the spring of this year, we saw in the EID Journal: MERS-CoV Infection, Replication & Transmission In Alpacas - a member of the same biological family (Camelidae) as dromedaries.

Despite several serological suveys, we've not seen any evidence that any other `farmed' animals have been naturally infected with the MERS virus in the Middle East. 

We've a new study in the journal Viruses - conducted by the same researchers from 2014 CSU study (along with researchers from the University of Queensland) -  that looks a the carriage and shedding of the MERS-CoV in experimentally infected horses, sheep and goats.

Somewhat reassuringly, the authors found:

Goats (n = 5) were evaluated for viral shedding, organ burden, and seroconversion and transmission to co-housed goats (n = 2). Limited viral shedding was observed without demonstration of viral transmission.
Due to the lack of transmission, only viral shedding and serology were evaluated in horses (n = 4) and sheep (n = 3). These animals did not become productively infected or seroconvert, indicating that such livestock are unlikely to serve as reservoirs for MERS-CoV and are unimportant in viral transmission.

The link to the (open access) report, and the abstract follow:

Inoculation of Goats, Sheep, and Horses with MERS-CoV Does Not Result in Productive Viral Shedding

Danielle R. Adney 1, Vienna R. Brown 1, Stephanie M. Porter 2, Helle Bielefeldt-Ohmann 3, Airn E. Hartwig 2 and Richard A. Bowen 1,2,*

Received: 17 June 2016 / Accepted: 13 August 2016 / Published: 19 August 2016

The Middle East respiratory syndrome coronavirus (MERS-CoV) was first recognized in 2012 and can cause severe disease in infected humans. Dromedary camels are the reservoir for the virus, although, other than nasal discharge, these animals do not display any overt clinical disease. 

Data from in vitro experiments suggest that other livestock such as sheep, goats, and horses might also contribute to viral transmission, although field data has not identified any seropositive animals. 
In order to understand if these animals could be infected, we challenged young goats and horses and adult sheep with MERS-CoV by intranasal inoculation. Minimal or no virus shedding was detected in all of the animals. During the four weeks following inoculation, neutralizing antibodies were detected in the young goats, but not in sheep or horses.

5. Conclusions

Current evidence suggests that dromedary camels are the primary reservoir of MERS-CoV. However, elucidating the role that other livestock such as goats, sheep, or horses could play in transmission is important for designing field studies and biosecurity strategies, and in assessing individuals at risk for viral transmission. While in vitro studies suggested that these animals could be naturally or experimental infected, the lack of support from field data coupled with the experimental data presented here suggest that these animals are unlikely to be infected and are not important in viral transmission of MERS-CoV.
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