Via Emerging Infectious Diseases, a letter: Ahead of Print -MERS-CoV Infection of Alpaca in a Region Where MERS-CoV is Endemic. Click or tap through for the full report and links to the documentation. Excerpt.
Accumulating evidence indicates that dromedaries (Camelus dromedarius) are a reservoir for zoonotic transmission of Middle East respiratory syndrome coronavirus (MERS-CoV). Although numerous studies have looked at other livestock in the Middle East region, evidence for MERS-CoV infection has only been found in dromedaries.
Extensive and continuous circulation of MERS-CoV occurs in the Al Shahaniya region of Qatar, most likely because of the presence of an international camel racing track and numerous barns holding camels. In April 2015, we investigated the MERS-CoV infection status of 15 healthy alpacas (Vicugna pacos) in a herd of 20 animals and 10 healthy dromedaries in a herd of 25 animals at a farm in this region (Technical Appendix[PDF - 394 KB - 2 pages]).
The herds were located at a distance of ≈200 m from each other within the barn complex and were cared for by the same animal workers, who lived in a common house between the herds at the complex. Both the alpacas and camels were kept as hobby animals.
Serum samples were collected from all 25 animals. Nasal swabs were collected from all camels, whereas nasal, rectal, and oral swab specimens were collected only from a subset of the alpacas (Technical Appendix[PDF - 394 KB - 2 pages]) because of logistical constraints.
The serum samples were tested for IgG antibodies reactive with the S1 antigens of MERS-CoV and severe acute respiratory syndrome coronavirus (SARS-CoV), and titers were calculated as described previously. MERS-CoV reactivity was confirmed by using a 90% plaque-reduction neutralization test (PRNT90). Swab specimens were analyzed for MERS-CoV RNA by a screening PCR targeting the upE gene.
MERS-CoV–specific antibodies were detected in all alpacas and all but 1 camel by protein microarray; reciprocal titers ranged from 49 to 773 for the alpacas and were >1,280 for the camels (Figure, panel A). PRNT90 testing confirmed the presence of MERS-CoV–specific antibodies; reciprocal neutralizing titers ranged from 80 to 320 for the alpacas and from 80 to >2560 for 9 camels (Figure, panel B). All swab specimens were negative by PCR (Technical Appendix[PDF - 394 KB - 2 pages]). None of the serum samples were reactive to SARS-CoV S1.
The microarray was also conducted for bovine CoV and human CoV-229E antigens, which were used as a proxy for the serologically closely related dromedary betacoronavirus-1 HKU23 and 229E-related camelid alphacoronaviruses, respectively. Positive binding was detected for both antigens in alpaca and dromedary (data not shown).
Our observations prove the susceptibility of alpacas for natural MERS-CoV infection and lay the foundation for future studies to determine the potential of alpacas as another livestock reservoir for MERS-CoV. The alpacas in this study were the only alpacas in Qatar at the time and were located in a region where MERS-CoV is endemic.