Aleutian disease is a highly contagious, always fatal illness that wreaks havoc on farmed and wild mink. The virus is present in the urine, feces, blood, and saliva of mink, and given the high density of fur farms, the disease can spread rapidly – and require the entire population to be euthanized. The physical symptoms include lethargic behaviour, loss of appetite, weight loss, and diarrhea. Once the symptoms are apparent, other infections such as pneumonia become common. There is no vaccine or cure for Aleutian and it can transfer from farmed populations to wild very easily.
In this most recent study, scientists looked to Newfoundland, which was devastated by an outbreak of AMDv in 2007. The study focused on the molecular epidemiology (the study of the molecular or genetic qualities of a disease) of the virus before and after the outbreak in Newfoundland within farmed and wild animals. They also compared this incident to global data – and the results were frightening.
“Approximately half of the [virus] sequences from Newfoundland wild mink were very close to those identified in farmed animals, suggesting a continuing exchange of viruses between wild and farmed populations, as reported in other locations,” the authors wrote.
The intensive conditions in which farmed mink are kept also creates ideal breeding ground for the virus, the study noted.
“Pathogen transmission is easier when the local host density is high and a fast turnover of individuals provides viruses the constant presence of a naïve population. During our study, we mainly analyzed viruses from farmed animals and it appears many of the wild animals analyzed may have acquired the infection from an original farm source.
But what is most alarming is that, as this virus has no cure and no vaccine, this cycle will not end for the farmed animals, or for wild animals nearby.
“These viruses can be transmitted to wild animals and exchanged between different farms and countries, where rapidly evolving viruses give rise to many novel parallel lineages.”