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Diseases of Aquatic Organisms

    DAO prepress abstract   -  DOI: https://doi.org/10.3354/dao03455

    Intestinal displacements in older harbour and grey seals

    E. Ludes-Wehrmeister, P. Wohlsein, E. Prenger-Berninghoff, C. Ewers, B. Woelfing, K. Lehnert, U. Siebert*

    *Corresponding author:

    ABSTRACT: Intestinal displacements including volvulus, torsion and invagination have been reported in different terrestrial and marine mammalian species. In this study pathological investigations were conducted on 157 individuals that had either stranded on the coasts of the North or Baltic Sea in the time period from 1996 to 2015 (115 harbour seals, over 19 months old, 21 grey seals, older than 13 months) or died in human care (18 harbour seals,older than 19 months, 3 grey seals, over 13 months old). Intestinal displacements were found in 23% of the examined free-living harbour seals, in 5% of the stranded grey seals, and in 17% of the harbour seals from human care. Intestinal volvulus, found in 24 cases, was characterized by twisting of the intestine along the mesenteric axis (180°-540°) resulting in vascular obstruction and haemorrhagic infarction. In harbour seals the sex ratio of individuals suffering from volvulus tended to be biased towards females during April to June suggesting an elevated risk for pregnant females around birth time. Invagination was detected in 11 cases, five of which suffered from additional volvulus. Pathological findings associated with intestinal volvulus and invagination were sero-haemorrhagic effusions in the abdominal cavity. Enteritis, parasitic infection with gastric nematodes and intestinal acanthocephalans and bacterial infection with predominantly Clostridium perfringens and Escherichia coli were observed in most of the affected animals. In total 30 investigated harbour and grey seals suffered from intestinal displacements. Pregnant females seemed to be more vulnerable around birth time. Causes of intestinal displacements remained undetermined, but are likely multifactorial.