Mink Farms Predict Aleutian Disease Exposure in Wild American Mink

Abstract

BackgroundInfectious diseases can often be of conservation importance for wildlife. Spillover, when infectious disease is transmitted from a reservoir population to sympatric wildlife, is a particular threat. American mink (Neovison vison) populations across Canada appear to be declining, but factors thus far explored have not fully explained this population trend. Recent research has shown, however, that domestic mink are escaping from mink farms and hybridizing with wild mink. Domestic mink may also be spreading Aleutian disease (AD), a highly pathogenic parvovirus prevalent in mink farms, to wild mink populations. AD could reduce fitness in wild mink by reducing both the productivity of adult females and survivorship of juveniles and adults.MethodsTo assess the seroprevalence and geographic distribution of AD infection in free-ranging mink in relation to the presence of mink farms, we conducted both a large-scale serological survey, across the province of Ontario, and a smaller-scale survey, at the interface between a mink farm and wild mink.Conclusions/SignificanceAntibodies to AD were detected in 29% of mink (60 of 208 mink sampled); however, seroprevalence was significantly higher in areas closer to mink farms than in areas farther from farms, at both large and small spatial scales. Our results indicate that mink farms act as sources of AD transmission to the wild. As such, it is likely that wild mink across North America may be experiencing increased exposure to AD, via disease transmission from mink farms, which may be affecting wild mink demographics across their range. In light of declining mink populations, high AD seroprevalence within some mink farms, and the large number of mink farms situated across North America, improved biosecurity measures on farms are warranted to prevent continued disease transmission at the interface between mink farms and wild mink populations.

Testing for Aleutian Mink Disease Virus in the River Otter (Lontra canadensis) in Sympatry with Infected American Mink (Neovison vison)

“…The disease occurs in wild and domesticated mink (Bloom et al 1994;Nituch et al 2011Nituch et al , 2012, and has been reported in many jurisdictions where domestic mink are raised; it is apparent that the commercial trade of domestic mink contributes to the spread of the virus (Bloom et al 1994;Nituch et al 2012). Aleutian mink disease virus can be highly prevalent in wild mink populations (Nituch et al 2011;Farid 2013) and mink farms can be point sources of disease (Nituch et al 2011), but the extent to which wild and domestic mink transmit AMDV, and other wildlife act as reservoirs, is unknown (Nituch et al 2012;Farid 2013). …”

“…Conversely, AMDV could spread from mink farms into the wild via the escape of infected individuals from farms, or through contact between wildlife and infected material on farms. For example, wildlife may visit composting mink carcasses or mink manure piles on farms (Nituch et al 2011). The virus can survive for more than 2 yr in soil and improperly composted manure or carcasses (Bloom et al 1994).…”

“…Given demonstrated global problems with mink farm biosecurity (Bonesi and Palazon 2007;Bowman et al 2007), there is potential for mink farms to be sources of cross-species spillover of AMDV (Nituch et al 2011(Nituch et al , 2012. Wildlife other than mink may also be sources of disease on farms (Farid 2013).…”

“…Experimental inoculation of one river otter with AMDV failed to elicit an immune response (Kenyon et al 1978), and it remains unclear whether otters could be important reservoirs of AMDV. We have extensively surveyed local freeranging mink populations in Ontario, Canada for AMDV (Nituch et al 2011(Nituch et al , 2012, and here used similar methods (an antibody test and real-time PCR for viral DNA) to survey sympatric river otters for AMDV.…”

“…We collected otter carcasses from fur trappers during the winters of 2011 and 2012 in the same geographic area as Nituch et al (2011) who found prevalence of AMDV antibody in mink to be 29% (Fig. 1).…”