Following up on my recent post about MRSP in rats, here’s a story about MRSA in an alpaca (Stull et al, Can Vet J 2012). As far as we know, it’s the first report of MRSA in an alpaca (or any camelid).
The report relates to our large animal hospital, where we perform MRSA screening of all horses at admission, weekly during hospitalization and at the time of discharge. It's all part of our infection control program, and the screening is designed to help reduce the risk to horses and our hospital personnel, since this multidrug-resistant bacterium is endemic in the Ontario (and broader) horse population, and outbreaks can occur in equine hospitals.
While alpaca’s aren’t horses, and we don’t see that many of them here, they sometimes get screened anyway since screening is being done on most of the other patients.
This case involved a neonatal alpaca that was admitted with its mother because of severe respiratory disease. The cria (baby alpaca) was very sick and was ultimately euthanized about 36 hours after admission.
Surprisingly, the admission MRSA sample from the cria was positive. In this case, MRSA wasn’t involved in the animal's illness. The cria didn’t have any evidence of bacterial infection, so this was an incidental (but interesting) finding.
When the bacterium was tested further, it was classified as CMRSA-5 (Canadian epidemic MRSA-5), a human strain that also predominates in horses in North America. The mother alpaca was MRSA negative. Presumably, the cria picked up MRSA from the farm environment or a person shortly after birth. MRSA (especially CMRSA-5) carriage rates are high amongst horse owners and horse vets compared to the general public, and it would have been nice to have determined if there were any horses on the alpaca’s home farm, but we couldn’t get any follow-up information.
This single case is probably of limited concern in the grand scheme of things. It’s likely an "oddball" infection rather than an indication that MRSA is a serious threat to alpacas, or that alpacas are a relevant source of human MRSA infection. However, that’s largely what was said when MRSA was first found in horses in the late 1990's and early 2000's, and it has since become a significant issue in that species, so the potential for MRSA to become a problem in alpacas can’t be completely dismissed.
If nothing else, the occurrence of this case is an indication of the need think broadly when it comes to infectious diseases, since many pathogens don’t have species boundaries. CMRSA-5 is a human-origin MRSA strain, but it’s worked its way outside of its natural host. It’s not the first and certainly won't be the last bug to make its way from people to animals.