Are we facing new health challenges and diseases in reindeer in Fennoscandia?

A large number of semi-domesticated reindeer is lost every year. Predators are the single most important factor for these losses, whereas restrictions on food availability some years also may cause high mortality. In the past, reindeer herding was challenged by severe infectious diseases, killing hundreds and thousands of animals, and having huge economic and social impact on reindeer herding in Fennoscandia. The general zoo-sanitary situation in Fennoscandia is very favourable for the time being, but reindeer herding is sometimes challenged by disease outbreaks, and diseases play an important role for survival and fitness of reindeer. Reindeer herding is also facing changes and challenges, which also may impact reindeer health and the disease status. Introduction of infectious agents not commonly present in the reindeer population may take place through import of animals, as well as by contact between reindeer, livestock and wildlife. Further, changes in the herding, such as increased feeding, transport, size of herds, animal density and stress load on the animals, may affect the animals ability to cope with infectious diseases. Also changes in weather conditions and climate, such as increased precipitation and mean temperature, may over time lead to restricted availability of pastures, changes in vegetation and changed conditions for parasites and insect vectors. These changes might be especially important for the reproductive success, including fitness of the calves during their first winter. To be able to cope with these changes and their potential impact on reindeer health, increased efforts should be made to gather reference data on health and disease parameters from the different reindeer herding districts, along with epidemiological risk factor analysis. This would increase the ability for the reindeer herding to cope with changes and to continue to produce quality meat products for the market

Characterisation of parapoxviruses isolated from Norwegian semi-domesticated reindeer (Rangifer tarandus tarandus)

BACKGROUND: Two outbreaks of the disease contagious ecthyma were reported in 1999 and 2000 in Norwegian semi-domesticated reindeer (Rangifer tarandus tarandus). Contagious ecthyma is an epidermal disease of sheep and goats worldwide, which is caused by the zoonotic parapoxvirus orf virus. Characterisation of clinical samples from the two outbreaks in semi-domesticated reindeer in Norway by electron microscopy and PCR (B2L) revealed typical parapoxvirus particles and partial gene sequences corresponding to parapoxvirus, respectively. If contagious ecthyma in reindeer is caused by orf virus, the virus may be transferred from sheep and goats, via people, equipment and common use of pastures and corrals, to reindeer. Another possibility is that contagious ecthyma in reindeer is caused by a hitherto unclassified member of the parapoxvirus genus that circulates among reindeer herds and remains endemic in Norway. RESULTS: Genomic comparisons of one standard orf strain (orf NZ2) and the reindeer isolates, employing restriction fragment length polymorphism (RFLP) and random amplified polymorphic DNA (RAPD) analysis, demonstrated high similarity between the reindeer viruses and known orf virus strains. Partial DNA sequences of two different viral genes were determined for the different isolates and compared with corresponding parapoxvirus genebank sequences. The comparison/alignment and construction of phylogenetic trees also point to an affiliation of the reindeer viruses to the species orf virus. CONCLUSION: The results of this work imply that the parapoxvirus causing contagious ecthyma in Norwegian semi-domesticated reindeer belongs to the species orf virus and that the orf virus crosses the host species barrier from sheep and goat to semi-domesticated reindeer

The Zoonotic Potential of Chronic Wasting Disease—A Review

Prion diseases are transmissible neurodegenerative disorders that affect humans and ruminant species consumed by humans. Ruminant prion diseases include bovine spongiform encephalopathy (BSE) in cattle, scrapie in sheep and goats and chronic wasting disease (CWD) in cervids. In 1996, prions causing BSE were identified as the cause of a new prion disease in humans; variant Creutzfeldt-Jakob disease (vCJD). This sparked a food safety crisis and unprecedented protective measures to reduce human exposure to livestock prions. CWD continues to spread in North America, and now affects free-ranging and/or farmed cervids in 30 US states and four Canadian provinces. The recent discovery in Europe of previously unrecognized CWD strains has further heightened concerns about CWD as a food pathogen. The escalating CWD prevalence in enzootic areas and its appearance in a new species (reindeer) and new geographical locations, increase human exposure and the risk of CWD strain adaptation to humans. No cases of human prion disease caused by CWD have been recorded, and most experimental data suggest that the zoonotic risk of CWD is very low. However, the understanding of these diseases is still incomplete (e.g., origin, transmission properties and ecology), suggesting that precautionary measures should be implemented to minimize human exposure.publishedVersio

Health and diseases of semi-domesticated reindeer in a climate change perspective

Climate change may affect reindeer herding and the health and disease of reindeer in several ways. One way of mitigating such changes is supplementary feeding, both in corrals and by bringing fodder to the animals on natural pastures. Feeding, when the right feed and feeding regime are used, may compensate for the loss of natural pastures and increase animal welfare. However, feeding may also cause issues with health and disease. These challenges may be associated with the feed and feeding regimes themselves, but also indirectly, by creating increased animal-to-animal contact and through the difficulty of maintaining hygienic conditions in corrals. In addition, climate change may have an impact on the presence of arthropod species and populations, such as ticks, mosquitoes and midges. These insects may cause increased levels of stress for the animals but can also be vectors for pathogens that may cause severe disease outbreaks, animal welfare issues and economic loss for reindeer herders. This chapter briefly presents the diseases and health problems that are directly or indirectly associated with reindeer feeding, as well as health challenges associated with arthropods and vector-borne diseases that are expected to be affected by climate change in the Arctic and sub-Arctic regions

Health and diseases of semi-domesticated reindeer in a climate change perspective

Climate change may affect reindeer herding and the health and disease of reindeer in several ways. One way of mitigating such changes is supplementary feeding, both in corrals and by bringing fodder to the animals on natural pastures. Feeding, when the right feed and feeding regime are used, may compensate for the loss of natural pastures and increase animal welfare. However, feeding may also cause issues with health and disease. These challenges may be associated with the feed and feeding regimes themselves, but also indirectly, by creating increased animal-to-animal contact and through the difficulty of maintaining hygienic conditions in corrals. In addition, climate change may have an impact on the presence of arthropod species and populations, such as ticks, mosquitoes and midges. These insects may cause increased levels of stress for the animals but can also be vectors for pathogens that may cause severe disease outbreaks, animal welfare issues and economic loss for reindeer herders. This chapter briefly presents the diseases and health problems that are directly or indirectly associated with reindeer feeding, as well as health challenges associated with arthropods and vector-borne diseases that are expected to be affected by climate change in the Arctic and sub-Arctic regions

A review of Brucella infection in marine mammals, with special emphasis on Brucella pinnipedialis in the hooded seal (Cystophora cristata)

Brucella spp. were isolated from marine mammals for the first time in 1994. Two novel species were later included in the genus; Brucella ceti and Brucella pinnipedialis, with cetaceans and seals as their preferred hosts, respectively. Brucella spp. have since been isolated from a variety of marine mammals. Pathological changes, including lesions of the reproductive organs and associated abortions, have only been registered in cetaceans. The zoonotic potential differs among the marine mammal Brucella strains. Many techniques, both classical typing and molecular microbiology, have been utilised for characterisation of the marine mammal Brucella spp. and the change from the band-based approaches to the sequence-based approaches has greatly increased our knowledge about these strains. Several clusters have been identified within the B. ceti and B. pinnipedialis species, and multiple studies have shown that the hooded seal isolates differ from other pinniped isolates. We describe how different molecular methods have contributed to species identification and differentiation of B. ceti and B. pinnipedialis, with special emphasis on the hooded seal isolates. We further discuss the potential role of B. pinnipedialis for the declining Northwest Atlantic hooded seal population

Persistence of antibodies in blood and body fluids in decaying fox carcasses, as exemplified by antibodies against Microsporum canis

To assist in evaluating serological test results from dead animals, 10 silver foxes (Vulpes vulpes) and 10 blue foxes (Alopex lagopus), 6 of each species previously vaccinated against and all challenged with Microsporum canis, were blood sampled and euthanased. Fox carcasses were stored at +10°C, and autopsy was performed on Days 0, 2, 4, 7, and 11 post mortem during which samples from blood and/or body fluid from the thoracic cavity were collected. Antibodies against M. canis were measured in an enzyme-linked immunosorbent assay (ELISA) as absorbance values (optical density; OD). To assess the degradation of antibodies, the ratio between post mortem and ante mortem absorbance was calculated. The mean absorbance from samples collected during autopsy was generally lower than from samples from live animals. In blood samples, this difference increased significantly with time (P = 0.04), while in body fluid samples the difference decreased (not significant; P = 0.18). We suggest that a positive serological result from testing blood or body fluid of a dead animal may be regarded as valuable, although specific prevalences obtained by screening populations based on this type of material may represent an under-estimation of the true antibody prevalence. Negative serological test results based on material from carcasses may be less conclusive, taken into account the general degradation processes in decaying carcasses, also involving immunoglobulin proteins

In vitro host range, multiplication and virion forms of recombinant viruses obtained from co-infection in vitro with a vaccinia-vectored influenza vaccine and a naturally occurring cowpox virus isolate

Background: Poxvirus-vectored vaccines against infectious diseases and cancer are currently under development. We hypothesized that the extensive use of poxvirus-vectored vaccine in future might result in co-infection and recombination between the vaccine virus and naturally occurring poxviruses, resulting in hybrid viruses with unpredictable characteristics. Previously, we confirmed that co-infecting in vitro a Modified vaccinia virus Ankara (MVA) strain engineered to express influenza virus haemagglutinin (HA) and nucleoprotein (NP) genes with a naturally occurring cowpox virus (CPXV-NOH1) resulted in recombinant progeny viruses (H Hansen, MI Okeke, Ø Nilssen, T Traavik, Vaccine 23: 499–506, 2004). In this study we analyzed the biological properties of parental and progeny hybrid viruses. Results: Five CPXV/MVA progeny viruses were isolated based on plaque phenotype and the expression of influenza virus HA protein. Progeny hybrid viruses displayed in vitro cell line tropism of CPXV-NOH1, but not that of MVA. The HA transgene or its expression was lost on serial passage of transgenic viruses and the speed at which HA expression was lost varied with cell lines. The HA transgene in the progeny viruses or its expression was stable in African Green Monkey derived Vero cells but became unstable in rat derived IEC-6 cells. Hybrid viruses lacking the HA transgene have higher levels of virus multiplication in mammalian cell lines and produced more enveloped virions than the transgene positive progenitor virus strain. Analysis of the subcellular localization of the transgenic HA protein showed that neither virus strain nor cell line have effect on the subcellular targets of the HA protein. The influenza virus HA protein was targeted to enveloped virions, plasma membrane, Golgi apparatus and cytoplasmic vesicles. Conclusion: Our results suggest that homologous recombination between poxvirus-vectored vaccine and naturally circulating poxviruses, genetic instability of the transgene, accumulation of non-transgene expressing vectors or hybrid virus progenies, as well as cell line/type specific selection against the transgene are potential complications that may result if poxvirus vectored vaccines are extensively used in animals and man