Infected Mink Research Articles

200 Transcriptomics analyses of mink spleen infected by Aleutian Disease

Abstract Aleutian disease (AD) is one of the most challenging mink diseases that causes high mortality and affects several economically important traits. Aleutian mink disease virus (AMDV) targets multiple organs and among them, the spleen is one of the major targeted organs. Transcriptomics has been widely used to reveal genes and biological pathways and identify biomarkers for early detection or prevention of diseases. This study aimed to identify genes and pathways related to the host response to AD infection in the spleen via transcriptomic study. Twelve (3 sets of 4 full-sibs) AMDV-free black male mink were housed in the clean section of the animal housing facility at the AD Research Centre (Truro, NS, Canada) between 4 to 7 d before inoculation. Before inoculation, sampling, and euthanasia, animals were anesthetized. The viral inoculum was a 10% (W/V) passage 2 of AMDV prepared from the spleens of mink infected with a local strain and stored at − 80 °C. Animals were intranasally inoculated under sedation with 60 µL of the viral homogenate, corresponding to approximately 300 to 700 ID50. Infected mink were humanely euthanized and the spleen tissues were collected for RNA isolation at 24h (d 1), 48h (d 2), and d 7. Libraries were prepared from total RNA using the Illumina TruSeqTM RNA kit, and were sequenced using the HiScanSQ platform, producing 101 bp reads from each end. The raw RNA-Seq data were cleaned using Cutadapt V1.4.2 and after the cleaning process was completed, 942,803,540 paired-end reads remained to be used in downstream analysis. Differential gene expression analyses revealed most (168) significant differentially expressed (DE) genes between d 1 and d 0 (Control or ADMV-free mink) while fewer DE genes (23) were between d 7 and d 0 (Table 1; Figure 1). A total of 19 DE genes are identified between three pair comparisons and seven of them are directly involved in immune response (FGL2, TLF8, LRP1, SERPINB9, MSR1, C3, PLA2R1, and XCR1). Gene enrichment analyses revealed pathways related to innate immune and fat metabolism which are important for the host mechanism to fight against infections. One of the important pathways is neutrophil degranulation which functions as aiding in the elimination of pathogens and the initiation of the inflammatory process. In conclusion, the current study provides insight into the transcriptomic profiles of the spleen in mink infected with AD. Identified candidate genes might be used for functional studies or as prior information for markers or genomic selection against AD in mink. Further studies in other tissues or single-cell RNA sequencing might deliver more comprehensive pictures of host responses to AD infections.

Rabies virus-based oral and inactivated vaccines protect minks against SARS-CoV-2 infection and transmission1

Minks are highly susceptible to SARS-CoV-2, and have transmitted SARS-CoV-2 to humans. Oral immunization is one of the most promising strategies to prevent SARS-CoV-2 infection and transmission in minks. Here, we generated three recombinant rabies viruses (RABV), rERAG333E/S6P, rERAG333E/DS6P and rERAG333E/BA2S6P, expressing the prefusion-stabilized SARS-CoV-2 spike protein of wild-type (S6P), δ (DS6P) or BA.2 (BA2S6P) strain based on an oral rabies vaccine candidate (rERAG333E). Oral or inactivated immunization of the three RABVs monovalent or trivalent were safe, and induced robust RABV neutralizing antibody and cross-antibody responses against the three SARS-CoV-2 in mice and minks. The challenge tests showed that two doses of rERAG333E-S6P as an oral or inactivated vaccine completely protected mice against mouse-adapted SARS-CoV-2 infection in the upper and lower respiratory tracts, and largely prevented viral replication and lung damage caused by wild-type SARS-CoV-2 infection in minks. Notably, we also confirmed that two doses of rERAG333E-S6P as an oral or inactivated vaccine can largely protect minks against wild-type SARS-CoV-2 transmission via respiratory droplets. Our findings suggest that rERAG333E-based COVID-19 vaccines appear to be suitable oral candidates to protect minks from SARS-CoV-2 infection and transmission, and may serve as inactivated vaccines for further investigation in humans.

Confirmation of the invasive American mink (Neogale vison) as carrier of Mycobacterium bovis in southern Chile

Bovine tuberculosis (bTB) is a chronic infectious-contagious disease with worldwide distribution, caused by the zoonotic pathogen Mycobacterium bovis. It is believed that the existence of wild cycles may hamper the success of bTB control strategies worldwide, where wildlife species could be reservoirs of this bacterial agent across their native (e.g., European badgers, wild boars) or non-indigenous (e.g., brushtail possum in New Zealand) ranges. However, further studies are required to understand the potential risk posed by non-native wildlife in becoming carriers of M. bovis in other neglected latitudes, such as the Southern Cone of South America. In this study, we performed a specific M. bovis-RD4 real-time PCR (qPCR) assay to detect bacterial DNA in tissues from the invasive American mink (Neogale vison) in Los Ríos region, Chile. We detected M. bovis DNA in blood samples collected from 13 out of 186 (7 %) minks with known sex and age. We did not find any significant differences in bacterial DNA detection according to mink sex and age. We found that 92 % (12/13) of specimens were positive in lung, 39 % (5/13) in mediastinal lymph node, and 15 % (2/13) in mesenteric lymph node, which suggest that both respiratory and digestive pathways as possible routes of transmission between infected hosts and minks. Our study is the first report on M. bovis molecular detection in invasive minks in an area where the largest cattle population in the country is located. Furthermore, this area is characterized by a low within-herd prevalence of M. bovis infection in cattle, with a relatively low number of infected herds, and so far, no attempts at eradicating the disease have been successful.

Prevalence of canine distemper in minks, foxes and raccoon dogs from 1983 to 2023 in Asia, North America, South America and Europe.

Canine distemper (CD) is a virulent disease caused by the canine distemper virus (CDV) in canines and mustelidaes with high mortality. The incidence of CDV is worldwide distribution and it has caused huge economic losses to multiple industries around the world. There are many studies investigating the prevalence of CD infection, but no comprehensive analysis of CDV infection in minks, foxes and raccoon dogs worldwide has therefore been carried out. The aim of this meta is to provide a comprehensive assessment of the prevalence of CDV infection in minks, foxes and raccoon dogs dogs through a meta-analysis of articles published from around the world. Data from 8,582 small carnivores in 12 countries were used to calculate the combined prevalence of CD. A total of 22.6% (1,937/8,582) of minks, foxes and raccoon dogs tested positive for CD. The prevalence was higher in Asia (13.8, 95% CI: 22.2-45.6), especially in South Korea (65.8, 95% CI: 83.3-95.8). Our study found that the incidence of CD was also associated with geographic climate, population size, health status, and breeding patterns. CD is more commonly transmitted in minks, foxes and raccoon dogs. However, the concentrated breeding as an economic animal has led to an increase in the prevalence rate. The difference analysis study recommended that countries develop appropriate preventive and control measures based on the prevalence in the minks, foxes, and raccoon dogs industries, and that reducing stocking density is important to reduce the incidence of CDV. In addition, CDV is more common in winter, so vaccination in winter should be strengthened and expanded to reduce the incidence of CD in minks, foxes and raccoon dogs.

Identifying selection signatures for immune response and resilience to Aleutian disease in mink using genotype data.

Aleutian disease (AD) brings tremendous financial losses to the mink industry. Selecting AD-resilient mink has been conducted to control AD. Such selections could have altered the patterns of genetic variation responding to selection pressures. This study aimed to identify selection signatures for immune response (IRE) and resilience to AD. A total of 1,411 mink from an AD-positive facility were used. For IRE, 264 animals were categorized according to the combined results of enzyme-linked immunosorbent assay (ELISA) and counterimmunoelectrophoresis (CIEP). For resilience, two grouping methods were used: 1) general resilience performance (GRP, n = 30) was evaluated based on the feed conversion ratio, Kleiber ratio, and pelt quality; and 2) female reproductive performance (FRP, n = 36) was measured based on the number of kits alive 24h after birth. Detection methods were the pairwise fixation index, nucleotide diversity, and cross-population extended haplotype homozygosity. A total of 619, 569, and 526 SNPs were identified as candidates for IRE, GRP, and FRP, respectively. The annotated genes were involved in immune system process, growth, reproduction, and pigmentation. Two olfactory-related Gene Ontology (GO) terms were significant (q < 0.05) for all traits, suggesting the impact of AD on the sense of smell of infected mink. Differences in detected genes and GO terms among different color types for IRE indicated variations in immune response to AD among color types. The mitogen-activated protein kinase (MAPK) signaling pathway was significant (q < 0.05) for FRP, suggesting that AD may disrupt MAPK signaling and affect FRP. The findings of this research contribute to our knowledge of the genomic architecture and biological mechanisms underlying AD resilience in mink.

PSXII-9 Identifying Selection Signatures for Immune Response and Resilience to Aleutian Disease in Mink Using Genotypes Data

Abstract Aleutian disease (AD), a severe immune-complex disease, brings tremendous financial losses to the mink industry. Resilience is the ability of an animal to minimize the influences caused by disturbances and maintain its performance under pathogen exposure. Many AD-positive farms have selected AD-resilient mink based on AD tests and/or AD-resilience indicator traits, such as growth, pelt quality, and reproduction. Selection based on these indicator traits may have changed the patterns of genetic variation and potentially represent a genomic signature that can be used to identify genes subjected to selection. Therefore, the main objective of this study was to identify the selection signatures related to immune response (IRE) and resilience to AD. . A total of 1,411 mink in five color types (black, demi, mahogany, pastel, and stardust) from the Canadian Centre for Fur Animal Research (Truro, Nova Scotia, Canada), which is an AD-positive facility, were genotyped using the Axiom Affymetrix Mink 70K single nucleotide polymorphism (SNP) panel. For the IRE trait, 264 mink were grouped into pairwise groups based on the combined results of counter-immunoelectrophoresis (CIEP) and enzyme-linked immunosorbent assay (ELISA) tests. Individuals in black (n = 29), demi (n = 131), mahogany (n = 76), and pastel (36) color types were also grouped based on combined results of CIEP and ELISA tests, respectively. For resilience traits, two methods were used to group CIEP-positive individuals into pairwise groups: 1) based on their general resilience performance (GRP, n = 30), which was measured by considering individual performance for feed conversion ratio, Kleiber ratio, and pelt quality, and 2) based on female reproductive performance (FRP, CIEP-positive dams only, n = 36), which was measured by the number of kits alive 24h after birth. The pairwise fixation index, nucleotide diversity, and cross-population extended haplotype homozygosity were used to detect selection signatures. Only SNPs detected by at least two methods were considered selection signatures candidates, including 619, 569, and 526 SNPs for IRE, GRP, and FRP traits, respectively. The genes annotated from the candidate SNPs were associated with previously reported traits influenced by AD, including immune system process, growth, reproduction, and pigmentation. Notably, two olfactory-related gene ontology (GO) terms were significant (q &amp;lt; 0.05) for all studied traits, suggesting AD might cause loss of smell in infected mink. Additionally, the differences in genes and GO terms detected across different color types for IRE indicated that mink of different color types may differ in immune response to AD. The mitogen-activated protein kinase (MAPK) signalling pathway was significant (q &amp;lt; 0.05) in Kyoto Encyclopedia of Genes and Genomes pathway analyses for FRP, indicating AD infection may disorder the MAPK signalling pathway, in turn influencing female reproductive performance. Our study has enhanced the understanding of genomic architecture underlying resilience of mink to AD and sheds light on the underlying biological mechanisms involved.

Investigation of the SARS-CoV-2 post-vaccination antibody response in Canadian farmed mink

Currently, SARS-CoV-2 have been detected in farmed mink in 13 different countries. Due to the high susceptibility and transmissibility among mink, great concerns of mink serving as a reservoir to generate novel variants with unknown virulence and antigenic properties arose. These concerns have consequently resulted in entire mink productions being culled and banned. This study investigates the post-vaccination antibody response in the Canadian farmed mink vaccinated with a commercial Index spike protein-based vaccine, approved for use in cats, and compares the antibody response to that observed post infection in Danish farmed mink. Blood samples were obtained from 50 mink at the Canadian Centre for Fur Animal Research (CCFAR), Dalhousie University (Truro, Canada). The sera were initially analyzed for antibodies by enzyme-linked immunosorbent assay (ELISA), and selected sera was subsequently tested in a virus neutralization tests. The levels of neutralizing antibodies were evaluated for an ancestral D614G strain and a recent circulating SARS-CoV-2 variant of concern (Omicron BA.4). The results revealed that the vaccine induced a strong antibody response in mink by reaching antibody titer levels of up to 1:12800 in the ELISA. Moreover, high levels of neutralizing antibodies were obtained, and despite the great level of genetic differences between the ancestral and Omicron BA.4 strains, the vaccinated mink showed high levels of cross-reacting neutralizing antibodies. Interestingly, the antibody levels towards SARS-CoV-2 in the Canadian vaccinated mink were significantly higher than observed in recently SARS-CoV-2 infected Danish mink and equal to anamnestic responses following re-infection. In conclusion, the vaccine used in the Canadian farmed mink was able to induce a strong and broad-reacting antibody response in mink, which could limit the spread of SARS-CoV-2 in farmed mink and thereby reduce the risk of mink serving as a SARS-CoV-2 reservoir for human infections.

Establishment and evaluation of a multiplex real-time RT-PCR for quantitative and differential detection of wild-type canine distemper virus from vaccine strains

This study sought to establish a real-time reverse transcription (RT)-PCR method to differentially detect canine distemper virus (CDV) wild-type and vaccine strains. To this end, a pair of CDV universal primers and two specific minor groove binder (MGB) probes, harboring a T/C substitution in the hemagglutinin (H) gene, were designed. Using a recombinant plasmid expressing the H gene of the CDV wild-type or vaccine strain as standards, a sensitive and specific multiplex real-time RT-PCR was established for quantitative and differential detection of CDV wild-type and vaccine strains. The limit of detection for this multiplex assay was 22.5 copies/μL and 2.98 copies/μL of viral RNA for wild-type and vaccine strains, respectively. Importantly, the wild-type and vaccine MGB probes specifically hybridized different genotypes of wild-type CDV circulating in China as well as globally administered vaccine viruses, respectively, with no cross-reactivity observed with non-CDV viruses. Moreover, this method was successfully applied for the quantitative detection of CDV RNA in tissue samples of experimentally infected breeding foxes, raccoon dogs, and minks. Additionally, the multiplex real-time RT-PCR was able to detect the viral RNA in the whole blood samples as early as 3 days post-infection, 3 to 4 days prior to the onset of clinical signs in these CDV infection animals. Hence, the established multiplex real-time RT-PCR method is useful for differentiating wild-type CDV and vaccine strains in China, and for conducting canine distemper early diagnosis as well as dynamic mechanism of CDV replication studies in vivo.

Mathematical Modeling of SARS-CoV-2 Transmission between Minks and Humans Considering New Variants and Mink Culling.

We formulated and studied mathematical models to investigate control strategies for the outbreak of the disease caused by SARS-CoV-2, considering the transmission between humans and minks. Two novel models, namely SEIR and SVEIR, are proposed to incorporate human-to-human, human-to-mink, and mink-to-human transmission. We derive formulas for the reproduction number R0 for both models using the next-generation matrix technique. We fitted our model to the daily number of COVID-19-infected cases among humans in Denmark as an example, and using the best-fit parameters, we calculated the values of R0 to be 1.58432 and 1.71852 for the two-strain and single-strain models, respectively. Numerical simulations are conducted to investigate the impact of control measures, such as mink culling or vaccination strategies, on the number of infected cases in both humans and minks. Additionally, we investigated the possibility of the mutated virus in minks being transmitted to humans. Our results indicate that to control the disease and spread of SARS-CoV-2 mutant strains among humans and minks, we must minimize the transmission and contact rates between mink farmers and other humans by quarantining such individuals. In order to reduce the virus mutation rate in minks, culling or vaccination strategies for infected mink farms must also be implemented. These measures are essential in managing the spread of SARS-CoV-2 and its variants, protecting public health, and mitigating the potential risks associated with human-to-mink transmission.

A comparison of sampling and testing approaches for the surveillance of SARS-CoV-2 in farmed American mink.

Surveillance for SARS-CoV-2 in American mink (Neovison vison) is a global priority because outbreaks on mink farms have potential consequences for animal and public health. Surveillance programs often focus on screening natural mortalities; however, significant knowledge gaps remain regarding sampling and testing approaches. Using 76 mink from 3 naturally infected farms in British Columbia, Canada, we compared the performance of 2 reverse-transcription real-time PCR (RT-rtPCR) targets (the envelope [E] and RNA-dependent RNA polymerase [RdRp] genes) as well as serology. We also compared RT-rtPCR and sequencing results from nasopharyngeal, oropharyngeal, skin, and rectal swabs, as well as nasopharyngeal samples collected using swabs and interdental brushes. We found that infected mink were generally RT-rtPCR-positive on all samples; however, Ct values differed significantly among sample types (nasopharyngeal < oropharyngeal < skin < rectal). There was no difference in the results of nasopharyngeal samples collected using swabs or interdental brushes. For most mink (89.4%), qualitative (i.e., positive vs. negative) serology and RT-rtPCR results were concordant. However, mink were positive on RT-rtPCR and negative on serology and vice versa, and there was no significant correlation between Ct values on RT-rtPCR and percent inhibition on serology. Both the E and RdRp targets were detectable in all sample types, albeit with a small difference in Ct values. Although SARS-CoV-2 RNA can be detected in multiple sample types, passive surveillance programs in mink should focus on multiple target RT-rtPCR testing of nasopharyngeal samples in combination with serology.

The Luciferase Immunoprecipitation System (LIPS) Targeting the Spike Protein of SARS-CoV-2 Is More Accurate than Nucleoprotein-Based LIPS and ELISAs for Mink Serology

Since anthropo-zoonotic outbreaks of SARS-CoV-2 have been reported in mink farms, it is important to monitor the seroprevalence within this population. To investigate the accuracy of nucleo (N) or spike (S) protein-based assays to detect anti-SARS-CoV-2 antibodies in animal serum, we compared four assays, two commercial N-based enzyme-linked immunosorbent assays (ELISA) validated for animal sera and two luciferase immunoprecipitation systems (LIPS-N and LIPS-S), to the reference standard plaque reduction neutralisation test (PRNT). Samples included in this study were derived from a naturally infected mink population. For the first time in this study, serum samples of mink were collected over a 307-day period, at different time points, thus providing an overview of performances of four different rapid serological tests over time. The assays were compared by performing a correlation analysis using R2, Spearman’s rank-order correlation coefficient, and Fleiss’ and Cohen’s kappa for analysis of agreement to PRNT, and an UpSet chart was created to visualize the number of shared positive samples between assays. Cohen’s kappa test on categorical data showed an excellent agreement between PRNT and LIPS-S, while agreements between PRNT and N-based methods decreased from fair for LIPS-N to poor agreements for the ELISA kits. In addition, LIPS-S revealed the highest number of true-positive SARS-CoV-2 samples compared to N-based methods. Despite an excellent agreement between LIPS-S and PRNT, a weak correlation was detectable between PRNT titres and relative light units. This study shows that the LIPS-S assay can be used for serological surveillance within a naturally exposed mink population, while N-based serological assays are less accurate providing a higher number of false-negative results, especially at a later stage of infection, thus indicating that N antibodies are less persistent in naturally exposed mink. Our findings provide crucial information for veterinarians and competent authorities involved in surveillance and outbreak investigation in wild and farmed minks.

Serum Analytes of American Mink (Neovison Vison) Challenged with Aleutian Mink Disease Virus.

Simple SummaryAleutian mink disease virus (AMDV) causes major health problems in the mink industry worldwide. The disease caused by AMDV has no cure or effective vaccine, and long-term viral eradication programs have failed in many countries. Some AMDV infected mink are genetically capable of tolerating the infection and living healthy and productive lives. Genetic selection for tolerance is, thus, a practical strategy to combat this virus. Accurate identification of tolerant animals is the fundamental issue in selection programs. The concentrations of some blood analytes, which are widely used as indicators of the presence and severity of diseases in humans and animals, are known to increase the accuracy of identifying tolerant mink. The objective of this study was to evaluate the merits of 14 serum analytes as biomarkers of tolerance to AMDV infection. Blood samples from 493 AMDV inoculated mink collected between 120 and 1211 days post-inoculation were analyzed. Total serum protein and globulin were found to be the most useful biomarkers of tolerance, whereas the relationships of other serum analytes to tolerance were weak or negligible.Black American mink (Neovison vison), which had been selected for tolerance to Aleutian mink disease virus (AMDV) for more than 20 years (TG100) or were from herds that have been free of AMDV (TG0), along with their progeny and crosses with 50% and 75% tolerance ancestry, were inoculated with a local isolate of AMDV. Blood samples were collected from 493 mink between 120 and 1211 days post-inoculation, and concentrations of 14 serum analytes were measured. Distributions of all analytes significantly deviated from normality, and data were analyzed after Box–Cox power transformation. Significant differences were observed among tolerant groups in the concentrations of globulin (GLO), total protein (TP), alkaline phosphatase, urea nitrogen, and calcium. Concentrations of GLO and TP linearly and significantly decreased with an increasing percentage of tolerance ancestry. Eleven analytes had the smallest values in the tolerant groups (TG100 or TG75), and eight analytes had the greatest values in the non-selected groups (TG0 or TG50). Antibody titer had the greatest correlation coefficients with GLO (0.62), TP (0.53), and creatinine (0.36). It was concluded that selection for tolerance decreased the concentrations of most serum analytes, and TP and GLO were the most accurate biomarkers of tolerance to AMDV infection. Males had significantly greater values than females for phosphorus and total bilirubin concentrations, but females had significantly greater amylase, cholesterol, and BUN concentrations than males.

Long-term antibody production and viremia in American mink (Neovison vison) challenged with Aleutian mink disease virus

BackgroundSelecting American mink (Neovison vison) for tolerance to Aleutian mink disease virus (AMDV) has gained popularity in recent years, but data on the outcomes of this activity are scant. The objectives of this study were to determine the long-term changes in viremia, seroconversion and survival in infected mink. Mink were inoculated intranasally with a local isolate of Aleutian mink disease virus (AMDV) over 4 years (n = 1742). The animals had been selected for tolerance to AMDV for more than 20 years (TG100) or were from herds free of AMDV (TG0). The progenies of TG100 and TG0, and their crosses with 25, 50 and 75% tolerance ancestry were also used. Blood samples were collected from each mink up to 14 times until 1211 days post-inoculation (dpi) and were tested for viremia by PCR and for anti-AMDV antibodies by counter-immunoelectrophoresis (CIEP). Viremia and CIEP status were not considered when selecting replacements. Low-performing animals were pelted and the presence of antibodies in their blood and antibody titer were measured by CIEP, and viremia and viral DNA in seven organs (n = 936) were tested by PCR.ResultsThe peak incidences of viremia (66.7%) and seropositivity (93.5%) were at 35 dpi. The incidence of viremia decreased over time while the incidence of seroconversion increased. The least-squares means of the incidence of PCR positive of lymph node (0.743) and spleen (0.656) were significantly greater than those of bone marrow, liver, kidneys, lungs and small intestine (0.194 to 0.342). Differences in tolerant ancestry were significant for every trait measured. Incidences of viremia over time, terminal viremia, seropositivity over time, AMDV DNA in organs and antibody titer were highest in the susceptible groups (TG0 or TG25) and lowest in the tolerant groups (TG100 or TG75).ConclusionPrevious history of selection for tolerance resulted in mink with reduced viral replication and antibody titer. Viremia had a negative effect and antibody production had a positive effect on survival and productivity.

Novel study on the prevalence of Trichinella spiralis in farmed American minks (Neovison vison) associated with exposure to wild rats (Rattus norvegicus) in China.

Minks and brown rats are reservoir hosts for many endoparasites including those of the genus Trichinella, a group of parasite nematodes with a worldwide distribution. However, little is known about the prevalence of Trichinella sp. infection in the American mink (Neovison vison) and rats (Rattus norvegicus) in China. Therefore, we aimed to examine the prevalence of Trichinella sp. infection in farmed minks in Weihai city, Shandong province, China and infer the possible route for Trichinella transmission to farmed American minks. In total, 289 muscle samples from minks and 102 carcasses of rats were collected from Weihai City. The appearance of Trichinella sp. was examined using the pooled artificial HCl-pepsin digestion method. The results showed that muscle larvae were detected in 20 of 289 minks (6.92%) and 2 of 102 synanthropic rats (1.96%). The larval density of Trichinella sp. in mink samples ranged from 0.025 to 0.815 larvae per gram (lpg), while the average larval burden in rats was 0.17 lpg. The isolates derived from minks and rats were identified at the species level using multiplex polymerase chain reaction (PCR), which revealed that the size of the two PCR products matched that of T.spiralis at 173 bp. Furthermore, sequence analysis showed 100% identity of the 5S rDNA inter-gene spacer regions of the two isolates to that of T.spiralis. This study presents a novel report of T.spiralis-mediated infection in minks and synanthropic rats in China. We highlight the vulnerability of farmed minks to Trichinella infection through exposure to synanthropic rats, which may raise a public health concern of potential zoonotic risks for domestic animals.

SARS-CoV-2 in mink farms in British Columbia, Canada: A report of two outbreaks in 2020-2021.

Since April 2020, mink have been recognized as a potential reservoir for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and a potential source of new variants. The objective of this report is to describe the epidemiological investigation and public health response to two coronavirus disease 2019 (COVID-19) outbreaks that involved both humans and farmed mink. An outbreak was declared on December 4, 2020, following detection of two COVID-19-positive farmworkers and elevated mink mortality on a mink farm (Farm 1) in British Columbia. The second cluster was detected on Farm 3 following detection of 1) a COVID-19 case among farm staff on April 2, 2021, 2) an indeterminate result from farm staff on May 11, 2021, and 3) subsequent SARS-CoV-2-positive mink in May 2021. Quarantine of infected farms, isolation of workers and their close contacts, and introduction of enhanced infection control practises were implemented to break chains of transmission. Among mink farmworkers, 11 cases were identified at Farm 1 and 6 cases were identified at Farm 3. On both Farm 1 and Farm 3, characteristic COVID-19 symptoms were present in farm employees before signs were observed in the minks. The viral sequences from mink and human samples demonstrated close genetic relation. Phylogenetic analyses identified mink intermediates linking human cases, suggesting anthropo-zoonotic transmission. These were the first COVID-19 outbreaks that included infected mink herds in Canada and identified potential anthropogenic and zoonotic transmission of SARS-CoV-2. We provide insight into the positive impact of regulatory control measures and surveillance to reduce the spillover of SARS-CoV-2 mink variants into the general population.

SARS-CoV-2 wildlife surveillance surrounding mink farms in British Columbia, Canada.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) can infect many wild and domestic animal species. Farmed American mink (Neovison vison) are particularly susceptible to infection. Outbreaks of SARS-CoV-2 were detected in farmed mink on three mink farms in British Columbia (BC), Canada between December 2020 and May 2021. In BC, mink farm density and proximity to wildlife habitats increase transmission risks from infected farmed mink. The objective of this study is to investigate the risk of SARS-CoV-2 spreading to and from wildlife in the area surrounding infected mink farms in BC, Canada, as well as to compare the effectiveness of physical and camera trapping surveillance methodologies. A combination of physical and camera trapping was used on and around three BC mink farms with active SARS-CoV-2 infections between January 22, 2021, and July 10, 2021. Samples from trapped animals, including escaped farmed mink, were tested for SARS-CoV-2. Camera images from one mink farm were reviewed to determine species and proximity to the mink barn. Seventy-one animals of nine species were captured and sampled. Three captured mink tested positive for SARS-CoV-2 by polymerase chain reaction and serology; the remaining samples were negative for SARS-CoV-2. Genotyping of the three positive mink indicated these were domestic (vs. wild) mink. A total of 440 animals of 16 species were photographed at the one farm where cameras were deployed. Detection of SARS-CoV-2 in escaped farmed mink is concerning and demonstrates the potential for transmission from farmed mink to wildlife, particularly given the observation of wildlife known to be susceptible to SARS-CoV-2 near infected mink farms. Combined use of physical and camera trapping contributed to the breadth of the results and is strongly recommended for future surveillance.

Bees can be trained to identify SARS-CoV-2 infected samples.

ABSTRACTThe COVID-19 pandemic has illustrated the need for the development of fast and reliable testing methods for novel, zoonotic, viral diseases in both humans and animals. Pathologies lead to detectable changes in the volatile organic compound (VOC) profile of animals, which can be monitored, thus allowing the development of a rapid VOC-based test. In the current study, we successfully trained honeybees (Apis mellifera) to identify SARS-CoV-2 infected minks (Neovison vison) thanks to Pavlovian conditioning protocols. The bees can be quickly conditioned to respond specifically to infected mink's odours and could therefore be part of a wider SARS-CoV-2 diagnostic system. We tested two different training protocols to evaluate their performance in terms of learning rate, accuracy and memory retention. We designed a non-invasive rapid test in which multiple bees are tested in parallel on the same samples. This provided reliable results regarding a subject's health status. Using the data from the training experiments, we simulated a diagnostic evaluation trial to predict the potential efficacy of our diagnostic test, which yielded a diagnostic sensitivity of 92% and specificity of 86%. We suggest that a honeybee-based diagnostics can offer a reliable and rapid test that provides a readily available, low-input addition to the currently available testing methods. A honeybee-based diagnostic test might be particularly relevant for remote and developing communities that lack the resources and infrastructure required for mainstream testing methods.

Histopathology and localization of SARS-CoV-2 and its host cell entry receptor ACE2 in tissues from naturally infected US-farmed mink (Neovison vison).

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) causes respiratory disease in mink similar to human COVID-19. We characterized the pathological findings in 72 mink from US farms with SARS-CoV-2 outbreaks, localized SARS-CoV-2 and its host cellular receptor angiotensin-converting enzyme 2 (ACE2) in mink respiratory tissues, and evaluated the utility of various test methods and specimens for SARS-CoV-2 detection in necropsy tissues. Of SARS-CoV-2-positive animals found dead, 74% had bronchiolitis and diffuse alveolar damage (DAD). Of euthanized SARS-CoV-2-positive animals, 72% had only mild interstitial pneumonia or minimal nonspecific lung changes (congestion, edema, macrophages); similar findings were seen in SARS-CoV-2-negative animals. Suppurative rhinitis, lymphocytic perivascular inflammation in the lungs, and lymphocytic infiltrates in other tissues were common in both SARS-CoV-2-positive and SARS-CoV-2-negative animals. In formalin-fixed paraffin-embedded (FFPE) upper respiratory tract (URT) specimens, conventional reverse transcription-polymerase chain reaction (cRT-PCR) was more sensitive than in situ hybridization (ISH) or immunohistochemistry (IHC) for detection of SARS-CoV-2. FFPE lung specimens yielded less detection of virus than FFPE URT specimens by all test methods. By IHC and ISH, virus localized extensively to epithelial cells in the nasal turbinates, and prominently within intact epithelium; olfactory mucosa was mostly spared. The SARS-CoV-2 receptor ACE2 was extensively detected by IHC within turbinate epithelium, with decreased detection in lower respiratory tract epithelium and alveolar macrophages. This study expands on the knowledge of the pathology and pathogenesis of natural SARS-CoV-2 infection in mink and supports their further investigation as a potential animal model of SARS-CoV-2 infection in humans.

Integrated histopathological, lipidomic, and metabolomic profiles reveal mink is a useful animal model to mimic the pathogenicity of severe COVID-19 patients

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is transmitted on mink farms between minks and humans in many countries. However, the systemic pathological features of SARS-CoV-2-infected minks are mostly unknown. Here, we demonstrated that minks were largely permissive to SARS-CoV-2, characterized by severe and diffuse alveolar damage, and lasted at least 14 days post inoculation (dpi). We first reported that infected minks displayed multiple organ-system lesions accompanied by an increased inflammatory response and widespread viral distribution in the cardiovascular, hepatobiliary, urinary, endocrine, digestive, and immune systems. The viral protein partially co-localized with activated Mac-2+ macrophages throughout the body. Moreover, we first found that the alterations in lipids and metabolites were correlated with the histological lesions in infected minks, especially at 6 dpi, and were similar to that of patients with severe and fatal COVID-19. Particularly, altered metabolic pathways, abnormal digestion, and absorption of vitamins, lipids, cholesterol, steroids, amino acids, and proteins, consistent with hepatic dysfunction, highlight metabolic and immune dysregulation. Enriched kynurenine in infected minks contributed to significant activation of the kynurenine pathway and was related to macrophage activation. Melatonin, which has significant anti-inflammatory and immunomodulating effects, was significantly downregulated at 6 dpi and displayed potential as a targeted medicine. Our data first illustrate systematic analyses of infected minks to recapitulate those observations in severe and fetal COVID-19 patients, delineating a useful animal model to mimic SARS-CoV-2-induced systematic and severe pathophysiological features and provide a reliable tool for the development of effective and targeted treatment strategies, vaccine research, and potential biomarkers.

The COVID-19 pandemic from a One Health perspective

The "One Health" approach is essential to better understand and manage a pandemic of animal origin. Sensitive geopolitical considerations seem to hamper the investigations into the origin of the pandemic, but everything points to the Rhinolophus bat as the starting point of this devastating pandemic. Through a phenomenon of reverse zoonosis, several hundred cases of contamination of animals by SARS-CoV-2 have been identified worldwide, involving about twenty species of mammals. The virus has also passed from animals to humans in the case of infected mink farms in Denmark or through contact with hamsters in Hong Kong. For the development of vaccines and treatments and to help detect COVID-19 in train stations or airports, the animal has confirmed its role as a valuable auxiliary resource for humans in the fight against the pandemic.