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High prevalence of Müllerian duct remnant cysts on the spermatic duct in wild Eurasian otters (Lutra lutra) from Sweden
Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Environmental toxicology. Enheten för miljöforskning, Naturhistoriska riksmuseet, Department of Environmental research, Swedish Museum of Natural History.
Enheten för patologi och viltsjukdomar, Statens veterinärmedicinska anstalt, Department of pathology and wildlife diseases, National Veterinary Institute.
2013 (English)In: PLoS ONE, ISSN 1932-6203, Vol. 8, no 12, e84660- p.Article in journal (Refereed) Published
Abstract [en]

The spermatic ducts (vasa deferentia) of 235 otters (Lutra lutra) found dead between 1999 and 2012 in Sweden were examined for presence of paraductular cysts. Single or multiple elongated uni- or bilateral cysts parallel to the spermatic duct were noted in 72% of the examined males. The cysts were adjacent to, but did not communicate with the lumen of the spermatic duct, and were usually located within a few centimeters of the testis and epididymis. The cysts are proposed to be congenital Mullerian duct remnants. Other morphologic abnormalities in the reproductive organs were not noted within this study. Possible causes of the incomplete regression of the embryonic female gonadal duct are exposure to environmental contaminants such as elevated concentrations of estrogen-like compounds (endocrine disrupting chemicals), inbreeding, or a naturally occurring anatomic defect. No obvious geographical pattern was observed for otters with or without cysts. This is the first study and description of cysts on the spermatic duct in otters.

Place, publisher, year, edition, pages
2013. Vol. 8, no 12, e84660- p.
Keyword [en]
Otter, Müllerian duct remnant, endocrine disrupting chemicals, Sweden
National Category
Developmental Biology
Research subject
Biology with specialization in Environmental Toxicology
URN: urn:nbn:se:uu:diva-199054DOI: 10.1371/journal.pone.0084660ISI: 000328882000157OAI: oai:DiVA.org:uu-199054DiVA: diva2:619322
Available from: 2013-05-03 Created: 2013-05-03 Last updated: 2014-01-27Bibliographically approved
In thesis
1. The Otter (Lutra lutra) in Sweden: Contaminants and Health
Open this publication in new window or tab >>The Otter (Lutra lutra) in Sweden: Contaminants and Health
2013 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

In the 1950s the otter started to decline in numbers and distribution in Sweden and other parts of Europe. In 1972 a game law came into force, listing otter as a species that if found dead should be reported and sent to the authorities. The numbers of dead otters reported from different areas indicate population status and distribution. Between 1970 and 2012, 832 otters were sent to the authorities, the majority (66%) during the last ten years. Most were killed in traffic accidents or drowned in fishing gear. However, the main cause of the decline is believed to be environmental contaminants. Experimental data show that a PCB residue level in muscle tissue of 12 mg/kg lw causes reproductive impairment in mink (Neovison vison), suggesting reproductive problems also in the highly PCB-exposed otters in Sweden. Since the bans of PCB and DDT in the mid-1970s, concentrations of these substances in otter and fish have decreased and the otter population is increasing.

Few pathological changes in otters have been found that can be related to high contaminant concentrations. However, we found a correlation between elevated PCB concentrations and alterations in bone mineral density. No relationship was seen between DDE and bone parameters.

The decline of the otter coincided with the decline of grey seals (Halichoerus grypus) and white-tailed sea eagles (Haliaeetus albicilla) in Sweden, all showing decreased reproductive outcome. Reproductive success started to increase for all of them around 1990 and during the same period concentrations of PCB and DDE have decreased in these species.

The body condition among female otters has increased over the study period, indicating an improved health status. However, we found a high prevalence (71%) of cysts on the spermatic duct in otters collected between 1999 and 2012, possibly caused by endocrine disrupting chemicals.

Although the organochlorine concentrations in otters have decreased, otters still face many problems. New threats to the otter population in Scandinavia are the perfluorinated chemicals, including PFOS and PFOA. Results in this thesis show an increasing trend for these compounds in otters up to 2011, including some extremely high concentrations of PFOS in otters from southern Sweden.

Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis, 2013. 47 p.
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology, ISSN 1651-6214 ; 1051
Otter (Lutra lutra), PCB, DDT, PFAAs, reproduction, bone, time trends
National Category
Developmental Biology
Research subject
Biology with specialization in Environmental Toxicology
urn:nbn:se:uu:diva-199068 (URN)978-91-554-8688-4 (ISBN)
Public defence
2013-06-11, Lindahlsalen, Norbyvägen 18A, Uppsala, 13:00 (English)
Available from: 2013-05-21 Created: 2013-05-03 Last updated: 2013-08-30Bibliographically approved

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