| 1. |
- Järhult, Josef D., et al.
(författare)
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Environmental levels of the antiviral oseltamivir induce development of resistance mutation H274Y in influenza A/H1N1 virus in mallards
- 2011
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Ingår i: PLOS ONE. - San Francisco, CA : Public Library of Science (PLoS). - 1932-6203. ; 6:9
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Tidskriftsartikel (refereegranskat)abstract
- Oseltamivir (Tamiflu®) is the most widely used drug against influenza infections and is extensively stockpiled worldwide as part of pandemic preparedness plans. However, resistance is a growing problem and in 2008-2009, seasonal human influenza A/H1N1 virus strains in most parts of the world carried the mutation H274Y in the neuraminidase gene which causes resistance to the drug. The active metabolite of oseltamivir, oseltamivir carboxylate (OC), is poorly degraded in sewage treatment plants and surface water and has been detected in aquatic environments where the natural influenza reservoir, dabbling ducks, can be exposed to the substance. To assess if resistance can develop under these circumstances, we infected mallards with influenza A/H1N1 virus and exposed the birds to 80 ng/L, 1 µg/L and 80 µg/L of OC through their sole water source. By sequencing the neuraminidase gene from fecal samples, we found that H274Y occurred at 1 µg/L of OC and rapidly dominated the viral population at 80 µg/L. IC₅₀ for OC was increased from 2-4 nM in wild-type viruses to 400-700 nM in H274Y mutants as measured by a neuraminidase inhibition assay. This is consistent with the decrease in sensitivity to OC that has been noted among human clinical isolates carrying H274Y. Environmental OC levels have been measured to 58-293 ng/L during seasonal outbreaks and are expected to reach µg/L-levels during pandemics. Thus, resistance could be induced in influenza viruses circulating among wild ducks. As influenza viruses can cross species barriers, oseltamivir resistance could spread to human-adapted strains with pandemic potential disabling oseltamivir, a cornerstone in pandemic preparedness planning. We propose surveillance in wild birds as a measure to understand the resistance situation in nature and to monitor it over time. Strategies to lower environmental levels of OC include improved sewage treatment and, more importantly, a prudent use of antivirals.
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| 2. |
- Jourdain, Elsa, et al.
(författare)
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Influenza Virus in a Natural Host, the Mallard : Experimental Infection Data
- 2010
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Ingår i: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 5:1
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Tidskriftsartikel (refereegranskat)abstract
- Wild waterfowl, particularly dabbling ducks such as mallards (Anas platyrhynchos), are considered the main reservoir of low-pathogenic avian influenza viruses (LPAIVs). They carry viruses that may evolve and become highly pathogenic for poultry or zoonotic. Understanding the ecology of LPAIVs in these natural hosts is therefore essential. We assessed the clinical response, viral shedding and antibody production of juvenile mallards after intra-esophageal inoculation of two LPAIV subtypes previously isolated from wild congeners. Six ducks, equipped with data loggers that continually monitored body temperature, heart rate and activity, were successively inoculated with an H7N7 LPAI isolate (day 0), the same H7N7 isolate again (day 21) and an H5N2 LPAI isolate (day 35). After the first H7N7 inoculation, the ducks remained alert with no modification of heart rate or activity. However, body temperature transiently increased in four individuals, suggesting that LPAIV strains may have minor clinical effects on their natural hosts. The excretion patterns observed after both reinoculations differed strongly from those observed after the primary H7N7 inoculation, suggesting that not only homosubtypic but also heterosubtypic immunity exist. Our study suggests that LPAI infection has minor clinically measurable effects on mallards and that mallard ducks are able to mount immunological responses protective against heterologous infections. Because the transmission dynamics of LPAIVs in wild populations is greatly influenced by individual susceptibility and herd immunity, these findings are of high importance. Our study also shows the relevance of using telemetry to monitor disease in animals.
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| 3. |
- Muradrasoli, Shaman, et al.
(författare)
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Prevalence and phylogeny of coronaviruses in wild birds from the Bering Strait area (Beringia)
- 2010
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Ingår i: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 5:10
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Tidskriftsartikel (refereegranskat)abstract
- Coronaviruses (CoVs) can cause mild to severe disease in humans and animals, their host range and environmental spread seem to have been largely underestimated, and they are currently being investigated for their potential medical relevance. Infectious bronchitis virus (IBV) belongs to gamma-coronaviruses and causes a costly respiratory viral disease in chickens. The role of wild birds in the epidemiology of IBV is poorly understood. In the present study, we examined 1,002 cloacal and faecal samples collected from 26 wild bird species in the Beringia area for the presence of CoVs, and then we performed statistical and phylogenetic analyses. We detected diverse CoVs by RT-PCR in wild birds in the Beringia area. Sequence analysis showed that the detected viruses are gamma-coronaviruses related to IBV. These findings suggest that wild birds are able to carry gamma-coronaviruses asymptomatically. We concluded that CoVs are widespread among wild birds in Beringia, and their geographic spread and frequency is higher than previously realised. Thus, Avian CoV can be efficiently disseminated over large distances and could be a genetic reservoir for future emerging pathogenic CoVs. Considering the great animal health and economic impact of IBV as well as the recent emergence of novel coronaviruses such as SARS-coronavirus, it is important to investigate the role of wildlife reservoirs in CoV infection biology and epidemiology.
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| 4. |
- Mårtensson, Fredrika, et al.
(författare)
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The role of greenery for physical activity play at school grounds
- 2014
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Ingår i: Urban Forestry & Urban Greening. - : Elsevier BV. - 1618-8667 .- 1610-8167. ; 13:1, s. 103-113
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Tidskriftsartikel (refereegranskat)abstract
- Greenery is assumed to promote physical activity at school grounds by facilitating open and flexible play situations that engage many children. The role of greenery for school ground activity was investigated at two schools, one of which contained a substantial amount of greenery and the other one little greenery. All in all 197 children from 4th (10-11 years) and 6th grade (12-13 years), were involved in a one week field study, documenting self-reported school ground use, their favourite places and favourite activities and counting their steps by pedometer. The most common school ground activities were related to the use of balls as part of different sports, games and other playful activity. The more extensive green areas belonged to children's favourite places, but were little used, whereas settings with a mix of green and built elements in proximity to buildings were well-used favourites. Physical activity in steps was similar at the two schools, but on average girls got less of the activity they need during recess. Greenery was found important by contributing to settings attractive to visit for girls as well as boys and for younger as well as older children, if located in ways that also supported peer interaction and various games. (C) 2013 Elsevier G'mbH. All rights reserved.
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| 5. |
- Jensen, Anna M, et al.
(författare)
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Shrubs protect oak seedlings against ungulate browsing in temperate broadleaved forests of conservation interest: A field experiment
- 2012
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Ingår i: Forest Ecology and Management. - : Elsevier BV. - 0378-1127 .- 1872-7042. ; 266, s. 187-193
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Tidskriftsartikel (refereegranskat)abstract
- In many oak-rich temperate broadleaved forests of conservation value, high ungulate browsing pressure restricts oak regeneration. We examined the protection of oak (Quercus sp.) seedlings from browsing provided by naturally occurring shrubs in 10 forests across southern Sweden over 3 years. We planted oak seedlings in four plots in each forest; two with naturally regenerated shrubs and two with no shrubs. Ungulate browsers were excluded from two plots at each site, one with and one without shrubs. Fencing provided the best protection against ungulate browsers for the seedlings. The probability of a seedling being browsed (browsing frequency) was approximately 20% units lower for individuals growing among shrubs than for individuals growing in the absence of shrubs. When browsing did occur, the intensity (measured as a reduction in height growth) was significantly lower for seedlings in shrubs. Regression analyses showed that browsing frequency increased on seedlings in tall shrubs, and decreased on seedlings that had been browsed previously. Browsing intensity decreased if the seedling grew in tall and dense shrubs. Browsing frequency and intensity increased on oak seedlings that over topped the shrub canopy. Increased abundance of the prickled Rubus idaeus and Rubus fruticosus coll. in plots with shrubs did not affect browsing frequency and intensity. Two and a half years after planting, oak seedling mortality increased by the presence of shrubs. Although shrubs restricted oak seedling growth, we conclude that shrubs initially facilitated oak regeneration by concealment, and subsequently by numeric dilution. Shrubs may be used to reduce browsing damages if long-term evaluation indicates a net positive outcome for oak survival and growth.
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| 6. |
- Ahsan, Murshidul, et al.
(författare)
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Handling and Welfare of Bovine Livestock at Local Abattoirs in Bangladesh
- 2014
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Ingår i: Journal of Applied Animal Welfare Science. - : Taylor & Francis. - 1088-8705 .- 1532-7604. ; 17:4, s. 340-353
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Tidskriftsartikel (refereegranskat)abstract
- The World Organization for Animal Health (OIE) allows rope casting and the tying of legs for nonhuman animals laughter without stunning. Thehandling and welfare of bovine livestock (Bosindicus and Bubalus bubalis) were studied in 8 local abattoirs in 5 districts of Bangladesh. A totalof 302 animals were evaluated. At the local abattoirs, approximately 1/3 of the cattle and water buffalo were eithere maciated orinjured/sick. The size and vigor of the animals determined the casting method. Small and weak animals were cast on concrete floors by lifting a foreleg followed by pushing, or simply by twisting the head of the animal and then binding the legs with rope. Vigorous animals such as buffalo were castusing ropes and human force. Bleeding was slow and flaying was sometimes initiated before the animals were unconscious. Pulling and tearing of the trachea and pouring of water into the exposed trache a shortly after cutting were also observed in some cases.The over all animal handling was unnecessarily rough and he OIE standards were not implemented. Animals are subjected to considerable mistreatment, and there is an urgent need for the training nde ducation of the staff in a battoirs concerning humanes laughtering practices as well as a need to build moderns laughtering plants in Bangladesh.
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| 7. |
- Bröjer, Caroline, et al.
(författare)
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Pathobiology and virus shedding of low-pathogenic avian influenza virus (A/H1N1) infection in mallards exposed to oseltamivir
- 2013
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Ingår i: Journal of Wildlife Diseases. - : Wildlife Disease Association. - 0090-3558 .- 1943-3700. ; 49:1, s. 103-113
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Tidskriftsartikel (refereegranskat)abstract
- Low-pathogenic avian influenza (LPAI) viruses in wild birds are important as they can constitute the basis for the development of highly pathogenic avian influenza viruses or form part of human-adapted strains with pandemic potential. However, the pathogenesis of LPAI viruses is not well characterized in dabbling ducks, one of the natural reservoirs of LPAI viruses. Between 21 September 2009 and 21 December 2009, we used real-time reverse transcriptase polymerase chain reaction (q-PCR), histopathology, and immunohistochemistry (IHC) to study Mallards (Anas platyrhynchos) infected with an influenza A/H1N1 virus isolated from a wild Mallard in Sweden. The ducks were either inoculated intraesophageally ("artificial infection") or infected by virus shed by other ducks in the experiment ("contact infection"). The ducks were subjected to three low concentrations (80 ng/L, 1 mu g/L, and 80 mu g/L) of the active metabolite of oseltamivir (Tamiflu (R)), oseltamivir carboxylate (OC), which resulted in the development of the viral resistance mutation H274Y at 1 and 80 mu g/L. The LPAI virus infection was localized to the intestinal tract and cloacal bursa except in one Mallard. The exception was a duck euthanized 1 day postinoculation, whose infection was located solely in the lung, possibly due to intratracheal deposition of virus. The intestinal infection was characterized by occasional degenerating cells in the lamina propria and presence of viral antigen as detected by IHC, as well as positive q-PCR performed on samples from feces and intestinal contents. Histopathologic changes, IHC positivity, and viral shedding all indicated that the infection peaked early, around 2 days postinfection. Furthermore, more viral antigen and viral RNA were detected with IHC and q-PCR in the proximal parts early in the infection. There was no obvious difference in the course of the infection in artificial versus contact infection, when the level of OC was increased from 80 ng/L to 1 mu g/L (based on IHC and q-PCR), when the level of OC was increased to 80 mu/L, or when the resistance mutation H274Y developed (based on q-PCR).
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| 8. |
- Anderbrant, Olle, et al.
(författare)
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Pheromone of the elm bark beetle Scolytus laevis (Coleoptera Scolytidae) : stereoisomers of 4-methyl-3-heptanol reduce interspecific competition
- 2010
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Ingår i: Chemoecology. - : Springer Science and Business Media LLC. - 0937-7409 .- 1423-0445. ; 20:3, s. 179-187
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Tidskriftsartikel (refereegranskat)abstract
- Stereoisomers of 4-methyl-3-heptanol (MH) are pheromone components of several Scolytus bark beetles. The elm bark beetle Scolytus laevis (Coleoptera: Scolytidae) has in previous studies been caught in traps baited with commercial MH containing all four stereoisomers, but the lure has been considered a weak attractant. In this study, we addressed the question whether stereospecific responses by S. laevis to stereoisomers of MH might contribute to its niche separation from other sympatric Scolytus species. Using GC-MS, we analyzed extracts of hindguts and abdomens from male and female S. laevis and the sympatric S. triarmatus. We also tested all four MH-stereoisomers individually and in combinations in the field to determine their role for S. laevis. All four stereoisomers were synthesized via a boronic ester method with 1,2-dicyclohexylethanediol as chiral director. In addition, the (3S,4R)-stereoisomer of MH was prepared through enantioselective, lipase-mediated transesterification of a mixture of the four stereoisomers of MH. Females of both species contained small amounts of syn-MH, and males contained trace amounts of anti-MH. The anti stereoisomer (3R,4S)-MH was attractive to male and female S. laevis, whereas the syn stereoisomer (3S,4S)-MH acted as an inhibitor or deterrent and reduced the catch when added to the attractive isomer. The syn isomer is the main aggregation pheromone component of the larger and sympatric S. scolytus and possibly also of S. triarmatus. The avoidance response of S. laevis to the (3S,4S)-stereoisomer may reduce interspecific competition for host trees.
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| 9. |
- Haemig, Paul D., et al.
(författare)
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Forecasting risk of tick-borne encephalitis (TBE): Using data from wildlife and climate to predict next year's number of human victims
- 2011
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Ingår i: Scandinavian Journal of Infectious Diseases. - : Informa UK Limited. - 1651-1980 .- 0036-5548. ; 43:5, s. 366-372
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Tidskriftsartikel (refereegranskat)abstract
- Background: Over the past quarter century, the incidence of tick-borne encephalitis (TBE) has increased in most European nations. However, the number of humans stricken by the disease varies from year to year. A method for predicting major increases and decreases is needed. Methods: We assembled a 25-y database (1984-2008) of the number of human TBE victims and wildlife and climate data for the Stockholm region of Sweden, and used it to create easy-to-use mathematical models that predict increases and decreases in the number of humans stricken by TBE. Results: Our best model, which uses December precipitation and mink (Neovison vison, formerly Mustela vison) bagging figures, successfully predicted every major increase or decrease in TBE during the past quarter century, with a minimum of false alarms. However, this model was not efficient in predicting small increases and decreases. Conclusions: Predictions from our models can be used to determine when preventive and adaptive programmes should be implemented. For example, in years when the frequency of TBE in humans is predicted to be high, vector control could be intensified where infested ticks have a higher probability of encountering humans, such as at playgrounds, bathing lakes, barbecue areas and camping facilities. Because our models use only wildlife and climate data, they can be used even when the human population is vaccinated. Another advantage is that because our models employ data from previously-established databases, no additional funding for surveillance is required.
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| 10. |
- Wallander, Håkan, et al.
(författare)
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Growth and carbon sequestration by ectomycorrhizal fungi in intensively fertilized Norway spruce forests
- 2011
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Ingår i: Forest Ecology and Management. - : Elsevier BV. - 0378-1127 .- 1872-7042. ; 262:6, s. 999-1007
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Tidskriftsartikel (refereegranskat)abstract
- A substantial portion of the carbon (C) fixed by the trees is allocated belowground to ectomycorrhizal (EM) symbionts, but this fraction usually declines after fertilization. The aim of the present study was to estimate the effect of optimal fertilization (including all the necessary nutrients) on the growth of EM fungi in young Norway spruce forests over a three year period. In addition, the amount of carbon sequestered by EM mycelia was estimated using a method based on the difference in delta(13)C between C(3) and C(4) plants. Sand-filled ingrowth mesh bags were used to estimate EM growth, and similar bags amended with compost made from maize leaves (a C(4) plant) were used to estimate C sequestration. Fertilizers had been applied either every year or every second year since 2002 and the estimates of EM growth started in 2007. The application of fertilizer reduced EM growth to between 0% and 40% of the growth in the control plots at one site (Ebbegarde), while no significant effect was found at the other three sites studied. The effect of the fertilizer was similar in sand-filled and maize-compost-amended mesh bags, but the total production of EM fungi was 3-4 times higher in maize-compost-amended mesh bags. The fertilizer tended to reduce EM growth more when applied every year than when applied every second year. The amount of C sequestered in maize-compost-amended mesh bags collected from unfertilized treatments was estimated to be between 0.2 and 0.7 mg C g sand(-1) at Ebbegarde and between 0.2 and 0.5 mg C g sand(-1) at Grangshammar. This corresponds to between 300 and 1100 kg C per ha, assuming a similar production in the soil as in the mesh bags. Fertilization at the Ebbegarde site reduced carbon sequestration, which confirmed the results based on estimates of fungal growth (ergosterol levels). A correlation was found between fungal biomass and delta(13)C in mesh bags amended with maize compost. Based on this, it was estimated that a fungal production of 1 mu g ergosterol corresponded to 0.33 mg of sequestered carbon. In conclusion, the effect of the fertilizer on EM growth seemed to be dependent on the effect of the fertilizer on tree growth. Thus, at Ebbegarde, were tree growth was less stimulated by the fertilizer, EM growth was reduced upon fertilization. At other sites, where tree growth was more stimulated, the fertilizer did not influence EM growth. The large amounts of carbon sequestered during the experiment may be a result of fungal residues remaining in the soil after the death of the hyphae.
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