Driving forces behind the evolution of the Aleutian mink disease parvovirus in the context of intensive farming

Abstract

Aleutian mink disease virus (AMDV) causes plasmacytosis, an immune complex-associated syndrome that affects wild and farmed mink. The virus can also infect other small mammals (e.g., ferrets, skunks, ermines, and raccoons), but the disease in these hosts has been studied less. In 2007, a mink plasmacytosis outbreak began on the Island of Newfoundland, and the virus has been endemic in farms since then. In this study, we evaluated the molecular epidemiology of AMDV in farmed and wild animals of Newfoundland since before the beginning of the outbreak and investigated the epidemic in a global context by studying AMDV worldwide, thereby examining its diffusion and phylogeography. Furthermore, AMDV evolution was examined in the context of intensive farming, where host population dynamics strongly influence viral evolution. Partial NS1 sequences and several complete genomes were obtained from Newfoundland viruses and analyzed along with numerous sequences from other locations worldwide that were either obtained as part of this study or from public databases. We observed very high viral diversity within Newfoundland and within single farms, where high rates of co-infection, recombinant viruses and polymorphisms were observed within single infected individuals. Worldwide, we documented a partial geographic distribution of strains, where viruses from different countries co-exist within clades but form country-specific subclades. Finally, we observed the occurrence of recombination and the predominance of negative selection pressure on AMDV proteins. A surprisingly low number of immunoepitopic sites were under diversifying pressure, possibly because AMDV gains no benefit by escaping the immune response as viral entry into target cells is mediated through interactions with antibodies, which therefore contribute to cell infection. In conclusion, the high prevalence of AMDV in farms facilitates the establishment of co-infections that can favor the occurrence of recombination and enhance viral diversity. Viruses are then exchanged between different farms and countries and can be introduced into the wild, with the rapidly evolving viruses producing many parallel lineages.

Full genetic characterization and epidemiology of a novel amdoparvovirus in striped skunk (Mephitis mephitis)

“…2, 6 Because of this, primers normally utilized for the molecular diagnosis of AMDV could be used to amplify SKAVs 10, 11 and the two viruses could be confused without a more thorough genetic characterization. In addition, this high genetic similarity most likely translates into an elevated antigenic similarity, which might result in cross-reactivity between antibodies and antigens of different viruses and result in misdiagnosis when immunological assays are employed.…”

A comparative molecular characterization of AMDV strains isolated from cases of clinical and subclinical infection

“…The isolated DNA was used as a template for amplification by PCR (Labcycler thermal cycler, SensoQuest, Germany), which was conducted in triplicate, for three different primer pairs, i.e. two amplifying a fragment of the VP2 protein (primer pairs RP2 and RP3) [11] and one amplifying a fragment of the NS protein (primer pair NS) [12]. The sensitivity of the reaction was verified by qPCR.…”

Occurrence of Aleutian mink disease in selected national mink farms in light of serological and molecular investigations

“…AMD najczę-ściej przebiega bezobjawowo (314), choć w przebiegu zakażenia obserwowano zaburzenia rozrodu, zmiany w okrywie włosowej oraz zmniejszenia przyrostów masy ciała (7,29). Klinicznie przebiega jako zapalenie płuc szczeniąt, zapalenie nerek lub mózgu, prowadząc do śmierci (2,16,21).…”

“…Wynikają one m.in. z faktu występowania zakażeń parwowirusowych u ludzi (5, 18) oraz moż-liwości ewolucji i powstawania klonów AMDV (6,7). Istnieją ponadto uzasadnione obawy szerzenia się zakażeń AMDV nie tylko wśród norek hodowlanych i dzikich, ale również u innych gatunków, np.…”