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- Britt-Marie, Bäcklin, et al.
(author)
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Temporal and Geographical Variation of Intestinal Ulcers in Grey Seals (Halichoerus grypus) and Environmental Contaminants in Baltic Biota during Four Decades
- 2021
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In: Animals. - : MDPI AG. - 2076-2615. ; 11:10, s. 2968-2968
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Journal article (peer-reviewed)abstract
- The prevalence of intestinal ulcers and parasites was investigated in 2172 grey seals (Halichoerus grypus) collected in the Baltic Sea and 49 grey seals collected outside the Baltic Sea (i.e., the Atlantic). An increase in frequency of ileocaeco-colonic ulcers was observed in the early 1980s, followed by a decrease in the mid-1990s. At the same time, there was an increase followed by a decrease in brominated flame retardants, Perfluorooctanesulfonic acid (PFOS) and cadmium levels in herring (Clupea harengus), the most common prey item in Baltic grey seal diet, as well as in another top predator in the Baltic, the common guillemot (Uria aalge). The frequency of intestinal ulcers was significantly related to the intensity of acanthocephalan parasites, the age of the seal and the region of the Baltic Sea. Perforation of the intestinal wall was the cause of death in 26 of the investigated Baltic grey seals. In contrast, none of the investigated Atlantic grey seals had intestinal ulcers. They showed a thin colonic wall and very few acanthocephalan parasites. The high prevalence of intestinal ulcers and the high parasite intensity appear to be unique to the Baltic population of grey seals.
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- Sandholt, Arnar K. S., et al.
(author)
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Genomic signatures of host adaptation in group B Salmonella enterica ST416/ST417 from harbour porpoises
- 2021
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In: Veterinary research (Print). - Springer Science and Business Media LLC : Springer Science and Business Media LLC. - 0928-4249 .- 1297-9716. ; 52:1
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Journal article (peer-reviewed)abstract
- A type of monophasic group B Salmonella enterica with the antigenic formula 4,12:a:- (“Fulica-like”) has been described as associated with harbour porpoises (Phocoena phocoena), most frequently recovered from lung samples. In the present study, lung tissue samples from 47 porpoises found along the Swedish coast or as bycatch in fishing nets were analysed, two of which were positive for S. enterica. Pneumonia due to the infection was considered the likely cause of death for one of the two animals. The recovered isolates were whole genome sequenced and found to belong to sequence type (ST) 416 and to be closely related to ST416/ST417 porpoise isolates from UK waters as determined by core-genome MLST. Serovars Bispebjerg, Fulica and Abortusequi were identified as distantly related to the porpoise isolates, but no close relatives from other host species were found. All ST416/417 isolates had extensive loss of function mutations in key Salmonella pathogenicity islands, but carried accessory genetic elements associated with extraintestinal infection such as iron uptake systems. Gene ontology and pathway analysis revealed reduced secondary metabolic capabilities and loss of function in terms of signalling and response to environmental cues, consistent with adaptation for the extraintestinal niche. A classification system based on machine learning identified ST416/417 as more invasive than classical gastrointestinal serovars. Genome analysis results are thus consistent with ST416/417 as a host-adapted and extraintestinal clonal population of S. enterica, which while found in porpoises without associated pathology can also cause severe opportunistic infections.
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- Stavenow, Jasmine, et al.
(author)
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Sowerby’s Beaked Whales (Mesoplodon bidens) in the Skagerrak and Adjacent Waters: Historical Records and Recent Post-Mortem Findings
- 2022
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In: Oceans. - : MDPI AG. - 2673-1924. ; 3:3, s. 250-267
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Journal article (peer-reviewed)abstract
- In contrast to sparse historical observational records, five Sowerby’s beaked whales (SBW) stranded and died in Swedish waters between 2015 and 2020. Here we summarize historical records of SBWs in the Skagerrak basin and adjacent waters. The three recent stranding events from Sweden are described, and the post-mortem findings, including diet analysis, from the five SBWs are presented. Of 30 historical records of SBWs observations since 1869, 13 (43%) were documented between 2010 and 2021, and records between July and November were the most frequent. The recent stranding events occurred in October 2015 (n = 1), August 2019 (n = 3) and July 2020 (n = 1). Four of the SBWs were examined through necropsy, and one was sampled in the field. They were all sub-adults and included a single female and four males. The causes of death were emaciation, euthanasia due to traumatic injury, and live stranding of undetermined cause. Two SBWs each had a focal bone lesion consistent with osteomyelitis. Other findings included pox-like dermatitis, trauma, focal granulomas in a lymph node and intestine, and ulceration of the stomach. CT scans were performed on the heads of two animals, with inconclusive results. Three SBWs had hard parts in the gastrointestinal tract that mainly consisted of otoliths from several fish species. An eDNA-analysis confirmed and supplemented the diet analysis, revealing 17 fish species in total, including species not previously described as prey for SBW, such as Pleuronectidae spp. The apparent increase in observational records since 2010 may indicate a shift in SBW distribution or changing threats to these animals. Our results support and expand theories on SBW movements and provide data on the biology and health of this poorly known species, which are valuable for conservation and legislation efforts.
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- Stokholm, Iben, et al.
(author)
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Screening for Influenza and Morbillivirus in Seals and Porpoises in the Baltic and North Sea
- 2023
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In: Pathogens. - : MDPI AG. - 2076-0817. ; 12:3, s. 357-357
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Journal article (peer-reviewed)abstract
- Historically, the seals and harbour porpoises of the Baltic Sea and North Sea have been subjected to hunting, chemical pollutants and repeated mass mortalities, leading to significant population fluctuations. Despite the conservation implications and the zoonotic potential associated with viral disease outbreaks in wildlife, limited information is available on the circulation of viral pathogens in Baltic Sea seals and harbour porpoises. Here, we investigated the presence of the influenza A virus (IAV), the phocine distemper virus (PDV) and the cetacean morbillivirus (CeMV) in tracheal swabs and lung tissue samples from 99 harbour seals, 126 grey seals, 73 ringed seals and 78 harbour porpoises collected in the Baltic Sea and North Sea between 2002–2019. Despite screening 376 marine mammals collected over nearly two decades, we only detected one case of PDV and two cases of IAV linked to the documented viral outbreaks in seals in 2002 and 2014, respectively. Although we find no evidence of PDV and IAV during intermediate years, reports of isolated cases of PDV in North Sea harbour seals and IAV (H5N8) in Baltic and North Sea grey seals suggest introductions of those pathogens within the sampling period. Thus, to aid future monitoring efforts we highlight the need for a standardized and continuous sample collection of swabs, tissue and blood samples across Baltic Sea countries.
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- Schmidt, Britta, et al.
(author)
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Liver histopathology of Baltic grey seals (Halichoerus grypus) over three decades
- 2020
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In: Environment International. - : Elsevier BV. - 0160-4120 .- 1873-6750.
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Journal article (peer-reviewed)abstract
- The liver plays an important role in the metabolism and elimination of endogenic and exogenic lipid-solublecompounds. Multiple studies have shown that polychlorinated biphenyls (PCB) and dichlorodiphenyl trichloroethane(DDT) lead to morphological changes in liver cells. The aim of the present study was therefore toanalyse liver changes over time in Baltic grey seals (Halichoerus grypus) and to correlate these with historical PCBand DDT contaminations. A total of 191 liver samples were collected between 1981 and 2015 in the Gulf ofBothnia and northern Baltic Proper. Six histological features were evaluated, including portal mononuclear cellinfiltration, random mononuclear cell infiltration, lipid granulomas, hepatocellular fat vacuoles, hepatic stellatecells and mild multifocal bile duct hyperplasia accompanied by portal fibrosis. Three of the six lesions showed asignificant correlation with age. Furthermore, a positive correlation between portal mononuclear cell infiltrationand mild multifocal bile duct hyperplasia was found. Additionally, lipid granulomas were significantly correlatedwith hepatic stellate cells. More importantly, hepatic stellate cells and mild multifocal bile duct hyperplasia werecorrelated with adipose tissue (blubber) concentrations of ƩPCB, measured in a subsample (n = 34) of all individuals.No correlation with lesions and ƩDDT concentrations were found. These results show that age is animportant factor for the development of these liver lesions, but PCBs burden may be an influencing factor. This isin agreement with previous studies of marine mammals in the Baltic Sea as well as in the Arctic. We thereforeconclude that not only age of the animals, but also exposure to PCBs should be taken into account when understandingand evaluating the current health status of Baltic grey seals.
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| 10. |
- Schmidt, Britta, et al.
(author)
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Variation in skull bone mineral density of ringed seals (Phoca hispida) from the Gulf of Bothnia and West Greenland between 1829 and 2019
- 2020
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In: Environment International. - : Elsevier BV. - 0160-4120 .- 1873-6750.
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Journal article (peer-reviewed)abstract
- Bone is remodelled constantly through a balance of bone formation and resorption. This process can be affectedby various factors such as hormones, vitamins, nutrients and environmental factors, which can create an imbalanceresulting in systemic or local bone alteration. The aim of the present study was to analyse the changes in bone mineral density (BMD) over time in skulls of ringed seals (Pusa hispida) from the Baltic and Greenland using museum samples. Overall, 303 skulls (102 Male, 89 Female, 112 unknown) were used for bone investigationsand were divided into three periods according to collection year: before 1958 (n = 167), between 1958 and 1989 (n=40) and after 1994 up to 2019 (n=96). All skulls were examined by dual-energy X-ray absorptiometryto obtain the BMD. Skull BMD of the Baltic seals was positively correlated with the historical polychlorinatedbiphenyls (PCB) contamination having potential effects on the constitution of bones. BMD fluctuated between the three study periods (LM: p-value < 0.001, F-value = 47.5) with the lowest BMD found between 1897 and 1957, in the Gulf of Bothnia, where the highest peak of contaminant concentration was in the second period. BMD levels increased with increasing PCB concentration (LM: p < 0.001). The Greenland population showed significant lower BMD levels in the pollution and post-pollution period than the Baltic population (LM:p < 0.001). It also revealed a higher BMD in males than in females (LM: p=0.03). In conclusion, the variations between 1829 and 2019 in the Baltic Sea and Greenland may to a certain extent reflect normal fluctuations; however, this study revealed several factors affecting BMD, including sex and PCB levels.
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