| 11. |
- Elmberg, Johan, 1960-, et al.
(författare)
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Potential disease transmission from wild geese and swans to livestock, poultry and humans : a review of the scientific literature from a One Health perspective
- 2017
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Ingår i: Infection Ecology & Epidemiology. - : Taylor & Francis Open: Creative Commons Attribution Non-Commercial / Co-Action Publishing. - 2000-8686 .- 2000-8686. ; 7:1
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Tidskriftsartikel (refereegranskat)abstract
- There are more herbivorous waterfowl (swans and geese) close to humans, livestock and poultry than ever before. This creates widespread conflict with agriculture and other human interests, but also debate about the role of swans and geese as potential vectors of disease of relevance for human and animal health. Using a One Health perspective, we provide the first comprehensive review of the scientific literature about the most relevant viral, bacterial, and unicellular pathogens occurring in wild geese and swans. Research thus far suggests that these birds may play a role in transmission of avian influenza virus, Salmonella, Campylobacter, and antibiotic resistance. On the other hand, at present there is no evidence that geese and swans play a role in transmission of Newcastle disease, duck plague, West Nile virus, Vibrio, Yersinia, Clostridium, Chlamydophila, and Borrelia. Finally, based on present knowledge it is not possible to say if geese and swans play a role in transmission of Escherichia coli, Pasteurella, Helicobacter, Brachyspira, Cryptosporidium, Giardia, and Microsporidia. This is largely due to changes in classification and taxonomy, rapid development of identification methods and lack of knowledge about host specificity. Previous research tends to overrate the role of geese and swans as disease vectors; we do not find any evidence that they are significant transmitters to humans or livestock of any of the pathogens considered in this review. Nevertheless, it is wise to keep poultry and livestock separated from small volume waters used by many wild waterfowl, but there is no need to discourage livestock grazing in nature reserves or pastures where geese and swans are present. Under some circumstances it is warranted to discourage swans and geese from using wastewater ponds, drinking water reservoirs, and public beaches. Intensified screening of swans and geese for AIV, West Nile virus and anatid herpesvirus is warranted.
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| 12. |
- Faurby, Sören, et al.
(författare)
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Variation in anhydrobiotic survival of two eutardigrade morphospecies : a story of cryptic species and their dispersal
- 2008
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Ingår i: Journal of Zoology. - 0952-8369 .- 1469-7998. ; 275:2, s. 139-145
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Tidskriftsartikel (refereegranskat)abstract
- Studies of geographic variation in anhydrobiotic tolerance may increase our understanding of the population dynamics of terrestrial meiofauna and the relative importance of local adaptation and microhabitat niche separation. Although anhydrobiosis in tardigrades has been studied extensively, few studies have dealt with intraspecific variation in survival and none of these included genetic data to validate the intraspecific nature of the comparisons. Such data are necessary when working with meiofauna as cryptic species are common. We analysed the anhydrobiotic survival and genetic variation in cytochrome oxidase subunit I of two eutardigrades (Richtersius coronifer and Ramazzottius oberhaeuseri) from Italy and Sweden to detect possible local adaptation. Survival was analysed as a multidimensional contingency table and showed that anhydrobiotic survival was higher in Sweden for Ra. oberhaeuseri whereas no significant geographic variation was found for Ri. coronifer. Our genetic analysis indicated the coexistence of two cryptic species of Ra. oberhaeuseri in Italy, only one of which was found in Sweden. It could not be determined whether the variation in Ramazzottius is intra- or interspecific due to the presence of these cryptic species. We suggest that geographic variation in anhydrobiotic survival may be a general phenomenon in tardigrades but further research is necessary to determine the degree of intraspecific variation. The genetic analysis showed indications of long-term isolation of the individual populations of Ri. coronifer but recent dispersal in one of the cryptic species of Ramazzottius. We found higher survival in Ra. oberhaeuseri than in Ri. coronifer. These results indicate a possible coupling between anhydrobiotic survival and dispersal rate.
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| 13. |
- Godhe, Anna, et al.
(författare)
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Polymerase chain reaction in detection of Gymnodinium mikimotoi and Alexandrium minutum in field samples from Southwest India
- 2001
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Ingår i: Marine Biotechnology. - 1436-2228 .- 1436-2236. ; 3:2, s. 152-162
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Tidskriftsartikel (refereegranskat)abstract
- Polymerase chain reaction (PCR) primers were constructed for the detection of two toxic dinoflagellate species, Gymnodinium mikimotoi and Alexandrium minutum. The primers amplified a product of expected size from cultured cells of G. mikimotoi and A. minutum. The species-specific primers targeting G. mikimotoi did not yield any product with a wide range of other cultured algae used as negative controls. Primers designed for A. minutum were species-group-specific since it PCR yielded a product from the closely related species A. ostenfeldii and A. andersonii, but not from other species of this genus tested. The confirmation of PCR products was performed by digestion of the products with restriction enzymes. Sensitivity analyses of the primers on DNA template from cultured cells was positive by PCR at a DNA template concentration of 1.5 x 10(-4) ng/microl (0.3 cells/L) for A. minutum, and at a DNA concentration of 2.5 x 10(-2) ng/microl (697 cells/L) for G. mikimotoi. The PCR method for detection of G. mikimotoi and A. minutum was applied on field samples collected with a plankton net. Gymnodinium mikimotoi could be detected in 11 field samples by microscopy, and all these field samples were positive by PCR. The cell counts of G. mikimotoi in simultaneously collected water samples ranged from 306 to 2077/L. Alexandrium minutum could be detected by microscopy in 3 different field samples. The cell counts in water samples collected at the same time as the net samples ranged from 115 to 1115 cells/L. Alexandrium minutum was detected by PCR in these field samples, with the exception of the sample displaying the lowest cell count (115 cells/L). Plankton samples that were negative by microscopy for any of the two target species were also negative by PCR. All the PCR products from field samples were confirmed by restriction enzyme digestion. The application of PCR-based detection of harmful algal bloom species for aquaculture and monitoring purposes in natural field samples is discussed.
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| 14. |
- Gunnarsson, Gunnar, 1976-, et al.
(författare)
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Disease dynamics and bird migration : linking mallards Anas platyrhynchos and subtype diversity of the influenza A virus in time and space
- 2012
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Ingår i: PLOS ONE. - 1932-6203. ; 7:4, s. e35679-
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Tidskriftsartikel (refereegranskat)abstract
- The mallard Anas platyrhynchos is a reservoir species for influenza A virus in the northern hemisphere, with particularly high prevalence rates prior to as well as during its prolonged autumn migration. It has been proposed that the virus is brought from the breeding grounds and transmitted to conspecifics during subsequent staging during migration, and so a better understanding of the natal origin of staging ducks is vital to deciphering the dynamics of viral movement pathways. Ottenby is an important stopover site in southeast Sweden almost halfway downstream in the major Northwest European flyway, and is used by millions of waterfowl each year. Here, mallards were captured and sampled for influenza A virus infection, and positive samples were subtyped in order to study possible links to the natal area, which were determined by a novel approach combining banding recovery data and isotopic measurements (δ2H) of feathers grown on breeding grounds. Geographic assignments showed that the core natal areas of studied mallards were in Estonia, southern and central Finland, and northwestern Russia. This study demonstrates a clear temporal succession of latitudes of natal origin during the course of autumn migration. We also demonstrate a corresponding and concomitant shift in virus subtypes. Acknowledging that these two different patterns were based in part upon different data, a likely interpretation worth further testing is that the early arriving birds with more proximate origins have different influenza A subtypes than the more distantly originating late autumn birds. If true, this knowledge would allow novel insight into the origins and transmission of the influenza A virus among migratory hosts previously unavailable through conventional approaches.
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| 15. |
- Kaur-Kahlon, G., et al.
(författare)
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Response of a coastal tropical pelagic microbial community to changed salinity and temperature
- 2016
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Ingår i: Aquatic Microbial Ecology. - 0948-3055 .- 1616-1564. ; 77:1, s. 37-50
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Tidskriftsartikel (refereegranskat)abstract
- Studies on the responses of tropical microbial communities to changing hydrographic conditions are presently poorly represented. We present here the results from a mesocosm experiment conducted in southwest (SW) coastal India to investigate how changes in temperature and salinity may affect a coastal tropic microbial community. The onset of algal and bacterial blooms, the maximum production and biomass, and the interrelation between phytoplankton and bacteria were studied in replicated mesocosms. The treatments were set up featuring ambient conditions (28 °C, 35 PSU), hyposalinity (31 PSU), warming (31 °C) and a double manipulated treatment with warming and hyposalinity (31 °C, 31 PSU). The hyposaline treatment had the most considerable influence manifested as significantly lower primary production, and the most dissimilar microphytoplankton species community. The increased temperature acted as a catalyst in the double manipulated treatment and higher primary production was maintained. We investigated the dynamics of the microbial community with a structural equation model approach, and found a significant interrelation between phytoplankton biomass and bacterial abundance. Using this methodology, it became evident that temperature and salinity changes, individually and together, mediate direct and indirect effects that influence different compartments of the microbial loop. In the face of climate change, we suggest that in relatively nutrient replete tropical coastal zones, salinity and temperature changes will affect nutrient assimilation with subsequent significant effects on the quantity of microbial biomass and production.
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| 16. |
- Lacoursière, Jean O., 1958-, et al.
(författare)
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Laboratory study of the influence of water temperature and pH on Bacillus thuringiensis var. israelensis efficacy against black fly larvae (Diptera: Simuliidae)
- 1988
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Ingår i: Journal of the American Mosquito Control Association. - 8756-971X .- 1943-6270. ; 4:1, s. 64-72
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Tidskriftsartikel (refereegranskat)abstract
- An experimental formulation of Bacillus thuringiensis var. israelensis was used in the laboratory to assess the influence of water temperature and pH on the relationship between concentration, duration of exposure, and mortality of the northern black fly species Simulium decorum and Prosimulium mixtum/fuscum group. Mortality increases in both species with increases in duration of exposure, concentration, temperature and pH. Onset of death is shortened by increase in concentration and temperature. As temperature rises, the concentration of B. t. i required to induce mortality decreases; the sharpest decline occurring between 12 and 18 degree C for S. decorum , and between 4 and 8 degree C for P. mixtum/fuscum larvae. Lower pH induces a loss of efficacy of the B. t. i. formulation on S. decorum larvae at 4 and 12 degree C.
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| 17. |
- Norén, Fredrik, et al.
(författare)
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Parvilucifera infectans norén et moestrup gen. et sp. nov. (perkinsozoa phylum nov.) : a parasitic flagellate capable of killing toxic microalgae
- 1999
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Ingår i: European Journal of Protistology. - 0932-4739 .- 1618-0429. ; 35:3, s. 233-254
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Tidskriftsartikel (refereegranskat)abstract
- The toxic dinoflagellate Dinophysis, collected on the Swedish West Coast, was found to contain round bodies previously interpreted as the result of sexual reproduction. After two weeks of darkness in the refrigerator, all Dinophysis had died, however, and round bodies were present. These proved to be sporangia of a parasitic protist, here named Parvilucifera infectans gen. et sp. nov. Its identity was examined by LM, EM, and DNA sequencing. It is related to Perkinsus, an oyster-killing protist, and Colpodella, a phagocytic protist. Perkinsus has been indicated by 18S rRNA sequencing to be related to dinoflagellates, and the opportunity was taken to examine the ultrastructure of the flagellar apparatus of Parvilucifera in detail. Parvilucifera and its allies, known as perkinsids, share features with both dinoflagellates and apicomplexans. They do not fit readily into any of these groups but appear to form a missing link between them. They are described as a taxon on level with the other alvelolate phyla, as Perkinsozoa phylum nov. Infection studies showed that Parvilucifera infectans infects several other dinoflagellates, notably Alexandrium spp. which are responsible for PSP (paralytic shellfish poisoning). A discussion of the ecological role, in terms of biocontrol of harmful algal blooms, is included.
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| 18. |
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| 19. |
- Rehnstam, Ann-Sofi, 1959-, et al.
(författare)
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Blooms of sequence-specific culturable bacteria in the sea
- 1993
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Ingår i: FEMS Microbiology Letters. - 0378-1097 .- 1574-6968. ; 102:3-4, s. 161-166
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Tidskriftsartikel (refereegranskat)abstract
- Using specific deoxyoligonucleotide probes we have discovered seasonally strong (up to ∼ 100%) dominance of bacteria hybridizing to a single probe, in near shore waters off Scripps pier (32°53′N; 117°15′W). The probes were designed from partially sequenced 16S rRNA (V3 domain) of isolated marine bacteria. The results indicate that this approach may be used for studies of bacterial populations in the marine environment. We have shown that a number of genotypes that at times are dominant in the natural assemblages are culturable (and not, ‘viable-but-unculturable’). Additionally, our data suggests that the discrepancy between viable counts and direct counts in sea water samples can be explained by low plating efficiency.
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| 20. |
- Rehnstam, Ann-Sofi, 1959-, et al.
(författare)
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Identification of Vibrio anguillarum in fish by using partial 16S rRNA sequences and a specific 16S rRNA oligonucleotide probe
- 1989
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Ingår i: Applied and Environmental Microbiology. - 0099-2240 .- 1098-5336. ; 55:8, s. 1907-1910
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Tidskriftsartikel (refereegranskat)abstract
- 16S rRNA from seven different Vibrio anguillarum strains was partially sequenced and compared. From this sequence information we could design a 25-base-long oligonucleotide and use it as a specific probe for identification of V. anguillarum. This was determined by RNA-DNA colony hybridization and slot-blot hybridization. Strong, specific hybridization to the probe was observed for all V. anguillarum strains tested. Furthermore, no cross-hybridization could be seen against five other bacterial species. The detection limit was 5 x 10(3) bacteria per ml. It was even possible to detect V. anguillarum, by slot-blot hybridization, directly in a homogenized kidney from a fish that had died of vibriosis. The partial sequence information revealed small but significant differences between strains of the same species. These sequence differences are sufficiently significant to allow serotyping on the RNA level. Comparing strains of different serotypes revealed a 10-base and an 11-base difference in V. anguillarum serotypes O8 and O9, respectively, in a 122-base partial sequence.
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