Molecular epidemiology of Aleutian disease virus in free‐ranging domestic, hybrid, and wild mink

Abstract

Aleutian mink disease (AMD) is a prominent infectious disease in mink farms. The AMD virus (AMDV) has been well characterized in Europe where American mink (Neovison vison) are an introduced species; however, in North America, where American mink are native and the disease is thought to have originated, the virus’ molecular epidemiology is unknown. As such, we characterized viral isolates from Ontario free‐ranging mink of domestic, hybrid, and wild origin at two proteins: NS1, a nonstructural protein, and VP2, a capsid protein. AMDV DNA was detected in 25% of free‐ranging mink (45 of 183), indicating prevalent active infection. Median‐joining networks showed that Ontario AMDV isolates formed two subgroups in the NS1 region and three in the VP2 region, which were somewhat separate from, but closely related to, AMDVs circulating in domestic mink worldwide. Molecular analyses showed evidence of AMDV crossing from domestic to wild mink. Our results suggest that AMDV isolate grouping is linked to both wild endogenous reservoirs and the long‐term global trade in domestic mink, and that AMD spills back and forth between domestic and wild mink. As such, biosecurity on mink farms is warranted to prevent transmission of the disease between mink farms and the wild.

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). …”

“…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 used known AMDVpositive mink (Nituch et al 2012) as positive controls. Otter and mink spleen tissues were extracted using QIAGEN DNeasy blood and tissue kit (Qiagen Inc., Mississauga, Ontario, Canada).…”

“…Counties in Ontario, Canada, where river otters (Lontra canadensis) were sampled and tested for Aleutian mink disease virus (AMDV). Shaded counties were previously found to contain American mink (Neovison vison) that were positive for AMDV (Nituch et al 2012), and river otters in the labeled counties were sampled during this study.…”